Hexa-Aluminat Mischkristallphasen in spinellhaltigen Feuerbetonen - Mineralogische Untersuchungen im System CaO-Al2O3-MgO - Spies, Alexandra; Bauer, Marius; Klaus, Sebastian; Buhr, Andreas; Göbbels, Matthias (Keramische Zeitschrift, 2020)
CRIS-Team Scopus Importer:2021-04-19

Hexaferrites an phase relations in the iron-rich part of the system Sr-La-Co-Fe-O - Langhof, Nico; Göbbels, Matthias (Journal of Solid State Chemistry, 2009)
The iron rich part of the system was examined in the temperature range of 1200-1380 °C in air, with focus on the solid solutions of M-type hexaferrites. Samples of suitable compositions were studied by electronprobe microanalysis (EPMA). Substituted Sr-hexaferrites in the system Sr-La-Co-Fe-O do not follow the 1:1 substitution mechanism of La/Co in M-type ferrites. Due to the presence and limited Co2+-incorporation Fe3+-ions are reduced to Fe2+ within the crystal lattice to obtain charge balance. In all examined M-type ferrites divalent iron is formed, even at 1200 °C. The substitution principle Sr2++Fe3+↔La3++(Fe2+, Co2+) yields to the general substitution formula for the M-type hexaferrite Sr2 +1 - x La3 +x Fe2 +x - y Co2 +y Fe3 +12 - x O19 (0≤x≤1 and 0≤y≤x). In addition Sr/La-perovskiteSS (SS=solid solution), Co/Fe-spinelSS, hematite and magnetite are formed. Sr-hexaferrite exhibits at 1200 °C a limited solid solution with small amounts of Fe2+ (SrFe12O19↔Sr0.3La0.7Co 0.5Fe2+0.2Fe11.3O 19). At 1300 and 1380 °C a continuous solid solution series of the M-type hexaferrite is stable. SrFe12O19 and LaCo0.4Fe2+0.6Fe11O 19 are the end members at 1300 °C. The maximum Fe2+O content is about 13 mol% in the M-type ferrite at 1380 °C LaCo0.1Fe2+0.9Fe11O19 © 2009 Elsevier Inc. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.hexafe
Keywords: Hexagonal ferrites; La-Co substitution; M-type; Solid solution; SrFe

Hierarchisch strukturierte zellulare Funktionsmaterialien aus Calcium-Aluminat-Zement - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Bauchemie - Von der Forschung zur Praxis, 2003)
UnivIS-Import:2015-03-09:Pub.2003.nat.dgeo.IGM.LM.hierar

High amplitude redox changes in the late Early Triassic of South China and the Smithian/Spathian extinction. - Wignall, P.B.; Joachimski, Michael; Bond, David; Grabs, Stephen; Sun, Si; Yan, B; Wang, Lina; Chen, Y.; Lai, Xulong; Sun, Yadong; Sun, Yadong (Palaeogeography, Palaeoclimatology, Palaeoecology, 2015)
The Early Triassic was a time of remarkably high temperatures, large carbon cycle perturbations and episodes of widespread ocean anoxia. The sediments in the Nanpanjiang Basin of South China provide superb opportunities to examine the sedimentary response to these extreme conditions especially during the crisis interval at the Smithian-Spathian (S-S) boundary. We have investigated a deep water section at Jiarong and a shallower water section at Mingtang. These contain a range of facies including black shales, micritic limestone units and rudaceous carbonate event beds that include flat pebble conglomerates and breccia debrites that bear similarities to the hybrid event beds seen in clastic turbidite successions.Redox proxies (pyrite framboids and trace metals) reveal that widespread anoxia in the late Smithian persisted into the Novispathodus pingdingshanensis Zone of the early Spathian before a sharp transition to highly oxygenated "griotte facies" (red marine strata) in the Icriospathodus collinsoni Zone that records an "oxic rebound". Benthic faunas are locally common but of low diversity and dominated by thin-shelled bivalves and ostracodes with small foraminifers and exceptionally rare fish remains. Bioturbation was intense only in the early-middle Spathian (I. collinsoni conodont zone) Griotte facies. Anoxia and extremely high temperatures probably played a role in severely restricting the abundance of fish and the small sizes of marine invertebrates at this time. The presence of ooids and seafloor fan cements in our study sections indicates highly saturated conditions rather than acidification at the end of the Smithian.
UnivIS-Import:2015-07-08:Pub.2015.nat.dgeo.IGM.LG.higham
Keywords: Carbon isotopes; Early Triassic; Redox changes; Smithian-Spathian extinction

High beta diversity in a Triassic reef basin assemblage - Roden, Vanessa; Kießling, Wolfgang (Crossing the Palaeontological- Ecological Gap, 2018)

High diversity in the Triassic Cassian Formation - Roden, Vanessa; Hausmann, Imelda M.; Seuß, Barbara; Nützel, Alexander; Kießling, Wolfgang (GeoBonn2018, Living Earth, 2018)
The Middle to Upper Triassic Cassian Formation (Dolomites, Northern Italy) is the most diverse early Mesozoic ecosystem worldwide. A compilation of taxa described from the Cassian Formation contains 1336 species after revision. The species richness is very high compared with other fossil lagerstätten known for their diversity. For example, 228 species are reported in the Early Cambrian Chengjiang biota, 280 from the Upper Carboniferous Mazon Creek fauna, 491 from the Eocene London Clay, 147 from the Lower Devonian Hunsrück Slate, a literature compilation of the Upper Carboniferous Finis Shale of Texas yields 332 species, and a total of 861 animal species is reported from the Upper Jurassic Solnhofen Formation. Although the Cassian Formation stands out in the fossil context, a much higher species richness is recorded in Recent tropical ecosystems. For example, a comprehensive survey in New Caledonia, south-west Pacific, yielded 2738 species of molluscs alone (P. Bouchet et al., 2002). With gastropods comprising 70 % of mollusc species (53 % of all species), it is clear that aragonite preservation has a large impact on the diversity of the Cassian fauna. In general, fossil lagerstätten can yield highly diverse communities due to preservational effects. To assess the degree to which the Cassian diversity is driven by a lagerstätten effect, we compare the proportion of stratigraphic singletons among well-known lagerstätten (Chengjiang biota, Hunsrück Slate, Mazon Creek fauna, Solnhofen, London Clay). Among those, the Cassian Formation yields the lowest proportion of singleton genera (17%), and next to lowest proportion of singleton species (68%). The lagerstätten effect is therefore lower than in most other datasets. We consequently conclude that intensive taxonomic work and preservational bias are not the only factors contributing to the high diversity. Beyond the large area (at least 500 km2) and variety of environments covered by the Cassian Formation, yielding a very high beta diversity (mean proportional dissimilarity of 0.94), as well as aragonite preservation, the favorable living conditions in this tropical reef-basin allowed a high dlyiverse fauna to flouris

High mantle temperatures following rifting caused by continental insulation - Brandl, Philipp; Regelous, Marcel; Beier, Christoph; Haase, Karsten (Nature Geoscience, 2013)
The distribution of continents is thought to influence the temperature of the underlying mantle. Over geological timescales, insulation effects generate a build-up of heat that may cause increased magmatism, such as flood basalt volcanism, and ultimately rift the continents, causing them to break apart and new ocean basins to form. Here we use analyses of the major element geochemistry of lava samples collected from oceanic crust in the Atlantic and Pacific oceans to quantify the effect of continental insulation. The lavas formed at mid-ocean ridges following continental rifting and break up, and preserve a record of upper mantle temperatures over the past 170 Myr. We find that samples from the Pacific Ocean - formed more than 2,000 km from the nearest continental margin - do not record raised mantle temperatures. In contrast, samples from the Atlantic Ocean that formed close to the margin of the rifted continent reveal an upper mantle temperature immediately after continental rifting that was up to 150C higher than the present-day average; mantle temperatures remained high for 60-70 Myr. We conclude that the Atlantic thermal anomaly was created by continental insulation, and persisted in the mantle beneath the Atlantic Ocean long after the continental fragments had dispersed.

High-pressure mafic oceanic rocks from the Makbal Complex, Tianshan Mountains (Kazakhstan & Kyrgyzstan): Implications for the metamorphic evolution of a fossil subduction zone. - Meyer, Melanie; Klemd, Reiner; Konopelko, Dmitry (Lithos, 2013)
The Makbal Complex in the western Tianshan Mountains of Kazakhstan and Kyrgyzstan consists of HP/UHP metasedimentary host rocks which enclose various HP mafic blocks or boudins. These mafic rocks comprise rare eclogites (sensu stricto and sensu lato), garnet amphibolites (retrograded eclogites) and a newly discovered glaucophanite (glaucophane-garnet-omphacite bearing rock).So far the Makbal Complex has been interpreted to predominantly consist of continental lithologies and the mafic rocks were considered as dismembered dikes intruding continental metasediments. This interpretation is mainly based on the geological relationship and bulk rock chemistry of the different rock types. It was further suggested that the continental lithologies of the Makbal Complex underwent eclogite-facies metamorphism in a former subduction zone.In the present study we combined conventional geothermometry, P-T pseudosection modeling and major and trace element whole rock geochemistry for different mafic samples (glaucophanite and eclogites (sensu lato)) in order to shed light on both the metamorphic evolution and the protoliths of the mafic HP rocks in the Makbal Complex.Prograde to peak-pressure clockwise P-T paths of glaucophanite and eclogites (sensu lato) were modeled using garnet isopleth thermobarometry. The results show that the glaucophanite and eclogite (sensu lato) samples experienced similar prograde P-T paths and slightly different peak metamorphic conditions at . 560. °C at 2.4. GPa for the former and between . 520. °C at 2.2. GPa and . 555. °C at . 2.5. GPa for the latter, corresponding to burial depths between 70 and 85. km.Whole rock major and trace element analyses and petrological evidence imply that the various rock types at the Makbal Complex most likely originated from different precursor rocks. Eclogites (sensu lato) are believed to represent strongly retrogressed former eclogite-facies rocks that had never been eclogites (sensu stricto, i.e. >70 vol.% garnet and omphacite) due to an unfavorable alkali-poor bulk composition (Na2O <1wt.%). The four high-pressure mafic samples investigated in this study originated from oceanic crust (Zr/Hf ratio of 33 to 35) which contradicts all previous studies suggesting a continental protolith for all mafic HP/UHP rocks at Makbal.The present study indicates that the mafic high-pressure rocks represent incoherent segments of exhumed oceanic crust. Juxtaposition of different mafic oceanic (this study) and continental rocks is suggested to be due to buoyancy-driven exhumation of the metasedimentary host rock in the subduction channel where dismembered fragments of the subducted oceanic crust were captured in different depths. © 2013 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.c3geoc.highpr
Keywords: Garnet isopleth thermobarometry; Makbal HP/UHP Complex; P-T pseudosection; Thermobarometry; Tianshan Mountains

High-pressure metamorphism in the Munchberg Gneiss Complex and the Erzgebirge Crystalline Complex: the influence of fluid and reaction kinetics - Schmädicke, Esther; et al. (Chemie Der Erde-Geochemistry, 1994)

High-resolution carbon isotope stratigraphy of the Lower and Middle Ordovician succession of the Yangtze Platform, China: Implications for global correlation - Wu, Rongchang; Calner, Mikael; Gong, Fangyi; Liu, Jianbo; Lehnert, Oliver; Luan, Xiaocong; Zhan, Renbin (Journal of the Geological Society, 2020)

High resolution correlation of the Homerian carbon isotope excursion (Silurian) across the interior of the Midland Platform (Avalonia), UK - Ray, David C.; Jarochowska, Emilia; Röstel, Philipp; Worton, Graham J.; Munnecke, Axel; Wheeley, James R.; Boomer, Ian (Geological Magazine, 2019)

High-resolution geochemical record of environmental changes during MIS 3 from the northern Alps (Nesseltalgraben, Germany) - Mayr, Christoph; Stojakowits, Philipp; Lempe, Bernhard; Blaauw, Maarten; Diersche, Volker; Grohganz, Madleen; Correa, Matthias López; Ohlendorf, Christian; Reimer, Paula; Zolitschka, Bernd (Quaternary Science Reviews, 2019)
Ravine slopes at the recently discovered Nesseltalgraben site in southeastern Germany provide a unique last glacial sediment record for the Northern Calcareous Alps. The 21 m-long profile is dominated by fine-grained lacustrine-palustrine sediments overlain by several metres of glacifluvial gravels and lodgement tills of the Last Glacial Maximum and underlain by a diamicton. The age model includes 29 radiocarbon analyses and one paleomagnetic anomaly (Laschamp event) together providing a modelled age range from c. 59 to 29.6 ka cal BP, i.e. Marine Isotope Stage (MIS) 3. Apart from a description of the lithofacies, X-ray-fluorescence (XRF) scanning and elemental analyses provide high-resolution records of the geochemical composition. Multivariate analyses of XRF data separate Ca from other major elements. Carbonate contents, represented by Ca and total inorganic carbon, reach maxima in repeatedly occurring calcareous silty to sandy layers and are related to glacigenic origin. These indicate repeated inner-alpine local glaciations during stadials of MIS 3. Scanning electron microscopy and XRF data confirm the detrital origin of these layers. In contrast, organic matter and elements more resistant to chemical weathering (Si, Ti, Zr) accumulated during interstadials and concurrently elevated Rb/Sr ratios indicate intensified weathering. The high-frequency proxy variations determined for Nesseltalgraben reflect interstadial-stadial climate variability comparable with oxygen-isotope records from Greenland ice cores and Alpine speleothems. Thus, Nesseltalgraben is among the very few independently dated sediment records from continental Europe covering the entire MIS 3 and reflecting the full Dansgaard-Oeschger climate variability.
CRIS-Team Scopus Importer:2019-07-02
Keywords: Central Europe; Dansgaard-Oeschger cycles; Glaciation; Grain-size analyses; Greenland interstadials; Lacustrine-palustrine sediment; Middle Würmian; Paleoclimatology; Pleistocene; Radiocarbon dating

High-resolution microtaphofacies analysis of a carbonate tidal channel and tidally influenced lagoon, Pigeon Creek, San Salvador Island, Bahamas - Jarochowska, Emilia (Palaios, 2012)
Taphonomic processes can substantially affect grain composition and textural parameters of carbonate sediment, but can also produce taphonomic signatures that provide supplemental information on the environment of deposition. The aim of the present study is a microtaphofacies analysis of a tidal channelmetahaline lagoon system (North Branch of Pigeon Creek, San Salvador Island, Bahamas). Samples (39 in total) were collected in 13 sites in three zones located along the channel: in the inlet, in the middle part, and in the inner lagoon. Grain composition and taphonomic features - abrasion, boring, calcification, encrustation, fragmentation, and dissolution - were recorded using (1) examination of loose grains belonging to the sand-size fraction, and (2) point counting in thin sections produced from sediment samples. Proportions of different grain types were not correlated in thin sections and loose sediment samples from the same sites, with the exception of algae, which were systematically recorded in thin section in higher proportions. In examination of loose grains, abrasion, fragmentation, and calcification were the most useful taphonomic features, but not in thin sections; only fragmentation rates were correlated between the two proxies. Taphonomic information did not distinguish new facies in surface sediment, but was useful in refining environmental resolution and broadened the interpretation of the environment of deposition. Discrimination between sites based on compositional and textural characteristics of the sediment was improved more by increasing the number of replicates by site than by inclusion of taphonomic data. Application of recognized microtaphofacies to the fossil record is limited, because very little of grain diversity and taphonomic information can be recovered from analysis of thin sections. © 2012 SEPM (Society for Sedimentary Geology).
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LP.highre

High-resolution SIMS oxygen isotope analysis on conodont apatite from South China and implications for the end-Permian mass extinction - Chen, Jun; Shen, Shu-Zhong; Li, Xian-Hua; Xu, Yi-Gang; Joachimski, Michael; Bowring, Samuel A.; Erwin, Douglas H.; Yuan, Dong-Xun; Chen, Bo; Zhang, Hua; Wang, Yue; Cao, Chang-Qun; et al. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2016)
Understanding the interplay of climatic and biological events in deep time requires resolving the precise timing and pattern of paleotemperature changes and their temporal relationship with carbon cycle variations and biodiversity fluctuations. In situ oxygen isotope analyses of conodont apatite from South China enables us to reconstruct high-resolution seawater temperature records across the Permian-Triassic boundary (PTB) intervals in the upper slope (Meishan), lower slope (Shangsi), and carbonate platform (Daijiagou and Liangfengya) settings. Constrained by the latest high-precision geochronological dates and high-resolution conodont biozones, we can establish the temporal and spatial patterns of seawater temperature changes and assess their potential connections with the carbon cycle disruption and biodiversity decline. We find a rapid warming of 10 °C during the latest Permian-earliest Triassic that postdated the onset of the negative shift in δC by 81 kyr (thousand years), the abrupt decline in δC by 32 kyr and the onset of mass extinction by 23 kyr, which contradicts previous claims that the extreme temperature rise started immediately before or coincided with the onset of mass extinction. Our new evidence indicates that climate warming was most likely not a direct cause for the main pulse of the end-Permian mass extinction (EPME), but rather a later participant or a catalyst that increased the pace of the biodiversity decline. In addition, a prominent cooling is recorded in the earliest Changhsingian, with the main phase (a drop of 8 °C in 0.2 Ma) confined to the lower part of the Clarkina wangi zone and synchronous with the positive limb of the carbon isotope excursion (CIE) around the Wuchiapingian-Changhsingian boundary (WCB) in Meishan and Shangsi. Further long-term and high-resolution studies from other sections are needed to confirm the full contexts and underlying dynamics of the WCB "cooling event".
Keywords: Climate warming; Conodont apatite; End-Permian mass extinction; Oxygen isotope; SIMS; South China

High-resolution stable carbon isotope monitoring indicates variable flow dynamic patterns in a deep saline aquifer at the Ketzin pilot site (Germany) - Nowak, Martin; van Geldern, Robert; Myrttinen, Anssi; Zimmer, Martin; Barth, Johannes (Applied Geochemistry, 2014)

High resolution tephrostratigraphy, fossil record and age of Carboniferous-Permian glaciomarine mudstones within the Dwyka Group of southern Namibia. - Bangert, Berthold; Stollhofen, Harald; Geiger, Markus; Lorenz, Volker (Communications - Geological Survey of Namibia, 2000)
The Carboniferous Dwyka Group in southern Namibia can be subdivided into four upward-fining deglaciation sequences, each capped by relatively fine-grained glaciolacustrine or glaciomarine deposits. The uppermost part of the second deglaciation sequence comprises a thick fossiliferous mudstone unit, referred to as the ”Ganigobis Shale Member”. An abundance of marine macro- and ichnofossils as well as extrabasinally derived ashfall tuff horizons characterise the mudstones and provide the basis for an integrated high-resolution biostratigraphic and tephrostratigraphic framework. The marine body and trace fossils record the extent of the first of a series of marine incursions into the disintegrating Gondwanan interior as early as the Carboniferous. Juvenile magmatic zircons separated from tuff horizons interbedded with the Ganigobis Shale Member yield SHRIMP-ages of 300-302 Ma. This dates the uppermost part of the second deglaciation sequence in southern Namibia to the late Carboniferous (Gzelian) and provides a minimum age for the onset of Karoo-equivalent marine deposition prior to the much more widespread Eurydesma transgression.
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LG.highre

High-resolution ultrasonic measurements as proxies to resolve clastic reservoir heterogeneity in a salt-cemented gas reservoir - Filomena, Claudio; Stollhofen, Harald; van Ojik, Kees (Aapg Bulletin, 2012)
Petrophysical properties and their heterogeneity within sandstone bodies are key parameters in the evaluation of hydrocarbon and geothermal reservoirs. However, common tools applied to constrain the porosity distribution pattern in borehole cores are commonly time consuming and destructive, or suffer from a resolution limited to the meter to decimeter scale. We examine the applicability of nondestructive high-resolution sonic (HRS) logging of well core sections in the ultrasonic frequency range as a method providing porosity proxy data at the centimeter scale in a clastic sedimentary sequence. The middle Soiling Sandstone Member, a gas-bearing reservoir offshore from the Netherlands, is used as a test sample. It consists almost entirely of clean, cross-bedded to massive eo-lian dune and dry sand-flat deposits that are salt plugged to variable degrees. Plots of HRS logging data versus core-plug porosity values show a positive linear relationship that develops the highest coefficient of determination (R = 0.86) in structureless eolian dune sands, most probably caused by the lack of bedding-related anisotropics there. Once calibrated for a particular facies type, this correlation enables the calculation of porosity proxy data from sonic transit time values, acquired at centimetric steps. High-resolution sonic logging thus contributes a reliable and time-efficient, highly spatially resolving quantification of reservoir heterogeneities at centimeter scale and turns out to be a suitable tool for the nondestructive in-situ detection of high-porosity zones in otherwise uniform sandstone successions. Moreover, plots of closely spaced HRS logging-derived porosity proxy data significantly improve interpolation between single, wider spaced core-plug porosity data points. Copyright © 2012. The American Association of Petroleum Geologists. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.highre

History and development of ABCDEFG: a data standard for geosciences - Petersen, Mareike; Glöckler, Falko; Kießling, Wolfgang; Döring, Markus; Fichtmüller, David; Laphakorn, Lertsutham; Baltruschat, Brian; Hoffmann, Jana (FOSSIL RECORD, 2018)
Museums and their collections have specially customized databases in order to optimally gather and record their contents and associated metadata associated with their specimens. To share, exchange, and publish data, an appropriate data standard is essential. ABCD (Access to Biological Collection Data) is a standard for biological collection units, including living and preserved specimen, together with field observation data. Its extension, EFG (Extension for Geo-science), enables sharing and publishing data related to paleontological, mineralogical, and petrological objects. The standard is very granular and allows detailed descriptions, including information about the collection event itself, the holding institution, stratigraphy, chemical analysis, and host rock. The standard extension was developed in 2006 and has been used since then by different initiatives and applied for the publication of collection-related data in domain-specific and interdisciplinary portals.

Hoanib River flood deposits of Namib Desert interdunes as analogues for thin permeability barrier mudstone layers in aeolianite reservoirs. - Stanistreet, Ian G.; Stollhofen, Harald (Sedimentology, 2002)
The ephemeral braided Hoanib River of NW Namibia flows for a few days a year, and only high discharges enable the river to pass through interdunal depressions within the northern Namib Desert dune field to the Atlantic. The dune field comprises mainly large transverse dunes resulting from predominant SSW winds. River flood deposits between aeolian dunes are analogous to mudstone layers conformably interbedded with ancient aeolianite dune foresets. Deep floods pond laterally to considerable depths (metres to >10 m) in adjacent interdunes, depositing mud layers (1–50 cm) to considerable heights on avalanche and stoss faces of bounding dunes. Fairly passive flooding only disturbs aeolian stratification minimally. Floodwater clay infiltrates and settles as an impermeable seal, with a flood pond on top, perched, above regional groundwater. Flood ponds evaporate slowly for long periods (>3 years). Early emergence desiccates higher parts of a mud layer. Subsequent floods can refill a predecessor pond, benefiting from the existing impervious seal. Potential preservation of such mud layers is lower on the stoss face, but high on the avalanche face after burial by subsequent dune reactivation and migration. The leeward (right) Hoanib bank, a dune stoss face, is river and wind eroded to exhume fossil interdune pond mud layers of an earlier Hoanib channel. The highly inclined layers are interbedded with dune avalanche foresets and represent the edges of two successive fossil ponds exposed in plan. Ancient flood pond mudstones occur in the Permian–Triassic hydrocarbon reservoir, the Sherwood Sandstone Group of the Cheshire Basin (Kinnerton Formation) and Irish Sea Basin and were previously used erroneously to argue against the aeolian origin of cross-bed sets. Hoanib studies show that primary river interaction with a dune field might preserve only localized erosional omission surfaces in ancient aeolianites, with little sandy barform preservation, prone to aeolian reworking. Around the main fluvial channel locus, however, flood pond mudstone layers should form a predictable halo, within which fluid permeability will decrease.
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LG.hoanib
Keywords: Aeolian dunes; aeolianite reservoir; flash flood; interdune; Namib desert; Namibia; permeability

Hollow rhodoliths increase Svalbard's shelf biodiversity - Teichert, Sebastian (Scientific Reports, 2014)
Rhodoliths are coralline red algal assemblages that commonly occur in marine habitats from the tropics to polar latitudes. They form rigid structures of high-magnesium calcite and have a good fossil record. Here I show that rhodoliths are ecosystem engineers in a high Arctic environment that increase local biodiversity by providing habitat. Gouged by boring mussels, originally solid rhodoliths become hollow ecospheres intensely colonised by benthic organisms. In the examined shelf areas, biodiversity in rhodolith-bearing habitats is significantly greater than in habitats without rhodoliths and hollow rhodoliths yield a greater biodiversity than solid ones. This biodiversity, however, is threatened because hollow rhodoliths take a long time to form and are susceptible to global change and anthropogenic impacts such as trawl net fisheries that can destroy hollow rhodoliths. Rhodoliths and other forms of coralline red algae play a key role in a plurality of environments and need improved management and protection plans.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LP.hollow
Keywords: biodiversity; boring bivalves; ecosystem engineers; habitat; Hiatella arctica; hollow rhodoliths; Lithothamnion glaciale; maërl; Svalbard

Holocene fluvial depositional regimes of the Huab River, Skeleton Coast, Namibia - Walsh, Ella; Caracciolo, Luca; Ravidà, Domenico; Burrough, Sallie; Thomas, David (Earth Surface Processes and Landforms, 2022)
Dryland fluvial systems respond to hydroclimate changes on Quaternary timescales, yet deciphering the palaeoenvironmental histories they preserve is often complex. Whilst hydrological signals are preserved in sediment stores as variations in sediment amount, character, and composition, studies in dryland settings such as Namibia that link sedimentological and compositional changes to palaeoflow are limited. Focusing on the Huab River, Skeleton Coast, this paper presents the first integrated study of textural, compositional, and stratigraphic features from a Namibian fluvial archive. Petrographic and heavy mineral assemblages from Raman laser spectroscopy are combined with lithostratigraphic and particle size analysis. Together with a chronology established through 42 optically stimulated luminescence ages, we reconstruct provenance, changes in river style, and fluvial response to climate. The Huab lithostratigraphic record details periods of flashy ephemeral flow interbedded with flow within well-defined channels. Compositional assemblages indicate that humid conditions during the early to mid-Holocene resulted in activation of sediment stores across the catchment. Episodic discharge within an ephemeral river from 12 to 9 ka was followed by a more sustained river flow in a channelized system from 7 to 5 ka. During the late Holocene, better hydraulic sorting, increased mechanical breakdown of polycrystalline grains, and flash flood lithofacies suggest that flow occurred within a more arid climate. This fine-scaled analysis of an ephemeral fluvial system indicates the utility of assessing compositional changes to distinguish between depositional regimes. This is an important approach for reconstructing fluvial response to climate and for obtaining palaeoenvironmental records from complex sedimentary archives in dryland river settings.
CRIS-Team Scopus Importer:2022-03-18
Keywords: facies analysis; heavy minerals; Holocene; Namibia; OSL dating; palaeoflow; petrography; Raman spectroscopy; sedimentary environment

Homogenizing and diversifying effects of intensive agricultural land-use on plant species beta diversity in Central Europe — A call to adapt our conservation measures - Buhk, Constanze; Alt, Martin; Steinbauer, Manuel; Beierkuhnlein, Carl; Warren, Steven D.; Jentsch, Anke (Science of the Total Environment, 2017)
The prevention of biodiversity loss in agricultural landscapes to protect ecosystem stability and functions is of major importance to stabilize overall diversity. Intense agriculture leads to a loss in species richness and homogenization of species pools, but the processes behind are poorly understood due to a lack of systematic case studies: The specific impacts by agriculture in contrast to other land-use creating open habitat are not studied as such landscapes hardly exist in temperate regions. Applying systematic grids, we compared the plant species distribution at the landscape scale between an active military training areas in Europe and an adjacent rather intensively used agricultural landscape. As the study areas differ mainly in the type of disturbance regime (agricultural vs. non-agricultural), differences in species pattern can be traced back more or less directly to the management. Species trait analyses and multiple measures of beta diversity were applied to differentiate between species similarities between plots, distance-decay, or nestedness. Contrary to our expectation, overall beta diversity in the agricultural area was not reduced but increased under agricultural. This was probably the result of species nestedness due to fragmentation. The natural process of increasing dissimilarity with distance (distance-decay) was suppressed by intense agricultural land-use, generalist and long-distance dispersers gained importance, while rare species lost continuity. There are two independent processes that need to be addressed separately to halt biodiversity loss in agricultural land. There is a need to conserve semi-natural open habitat patches of diverse size to favor poor dispersers and specialist species. At the same time, we stress the importance of mediating biotic homogenization caused by the decrease of distance-decay: The spread of long-distance dispersers in agricultural fields may be acceptable, however, optimized fertilizer input and erosion control are needed to stop the homogenization of environmental gradients due to nitrogen input into semi-natural habitat.
Keywords: Biotic homogenization; Conservation; Dissimilarity; Distance-decay; Intense agricultural land-use; Landscape eutrophication

Host-Guest Complexes of [TriPip222], the Piperazine Analogue of [2.2.2]: Prediction of Ion Selectivity by Quantum Chemical Calculations VIII[#] - Begel, Svetlana; Scheurer, Andreas; Puchta, Ralph; van Eldik, Rudi (Zeitschrift für Anorganische und Allgemeine Chemie, 2016)
Keywords: Cryptand; Complexation; Quantum chemical calculation; Host-guest complex

Hotspots of cenozoic tropical marine biodiversity - Yasuhara, Moriaki; Huang, Huai Hsuan May; Reuter, Markus; Tian, Skye Yunshu; Cybulski, Jonathan D.; O'Dea, Aaron; Mamo, Briony L.; Cotton, Laura J.; Martino, Emanuela Di; Feng, Ran; Tabor, Clay R.; Reygondeau, Gabriel; et al. (CRC Press, 2022)
Hotspots of tropical marine biodiversity are areas that harbour disproportionately large numbers of species compared to surrounding regions. The richness and location of these hotspots have changed throughout the Cenozoic. Here, we review the global dynamics of Cenozoic tropical marine biodiversity hotspots, including the four major hotspots of the Indo-Australian Archipelago (IAA), western Tethys (present Mediterranean), Arabian Sea and Caribbean Sea. Our review supports the 'Hopping Hotspots' model, which proposes that the locations of peak biodiversity are related to Tethyan faunai elements and track broad-scale shallow-marine habitats and high coastal complexity created by the collision of tectonic plates. A null hypothesis is the 'Whack-A-Mole' model, which proposes that hotspots occur in habitats suitable for high diversity regardless of taxonomie identity or faunai elements. Earlier 'Centre-of theories (e.g. centres of origin with diversity decreasing with distance from supposed areas of exceptionally high rates of speciation, for which easy connection to adjacent regions to the east and west is important) were based on the analysis of recent biotas with no palaeontological foundation, and may better explain diversity dynamics within a hotspot rather than those between hotspots. More recently, however, human disturbance is massively disrupting these natural patterns.
CRIS-Team Scopus Importer:2022-12-23
Keywords: Fossil records; Global patterns; Neogene; Paleobiology; Paleogene; Species diversity gradients; Tropics

How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Furth, Germany - Köhler, Inga; Martinez, Raul E.; Piatka, David; Herrmann, Achim J.; Gallo, Arianna; Gehringer, Michelle M.; Barth, Johannes (Biogeosciences, 2021)
At present most knowledge on the impact of iron on O-18 / O-16 ratios (i.e. delta O-18) of dissolved oxygen (DO) under circum-neutral conditions stems from experiments carried out under controlled laboratory conditions. These showed that iron oxidation leads to an increase in delta O-18(DO) values. Here we present the first study on effects of elevated Fe(II) concentrations on the delta O-18(DO) in a natural, iron-rich, circum-neutral watercourse. Our results show that iron oxidation was the major factor for rising dissolved oxygen isotope compositions in the first 85m of the system in the cold season (February) and for the first 15m during the warm season (May). Further along the course of the stream, the delta O-18(DO) decreased towards values known for atmospheric equilibration around +24.6 parts per thousand during both seasons. Possible drivers for these changes may be reduced iron oxidation, increased atmospheric exchange and DO production by oxygenic phototrophic algae mats. In the cold season, the delta O-18(DO) values stabilized around atmospheric equilibrium, whereas in the warm season stronger influences by oxygenic photosynthesis caused values down to +21.8 parts per thousand. In the warm season from 145m downstream of the spring, the delta O-18(DO) increased again until it reached atmospheric equilibrium. This trend can be explained by respiratory consumption of DO combined with a relative decrease in photosynthetic activity and increasing atmospheric influences. Our study shows that dissolved Fe(II) can exert strong effects on the delta O-18(DO) of a natural circum-neutral spring system even under constant supply of atmospheric O-2. However, in the presence of active photosynthesis, with supply of O-2 to the system, direct effects of Fe oxidation on the delta O-18(DO) value become masked. Nonetheless, critical Fe(II) concentrations may indirectly control DO budgets by enhancing photosynthesis, particularly if cyanobacteria are involved.
CRIS-Team WoS Importer:2021-08-20

How C12A7 influences the early hydration of calcium aluminate cement at different temperatures - Köhler, Andreas; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2022)
Calcium aluminate cement (CAC) can contain mayenite (C12A7) as a minor phase which can influence the early hydration. Since CAC hydration is known to be extremely temperature dependent, this study presents the valuable effect of C12A7 dissolution on the early hydration at different temperatures (10, 23 and 35 °C). A reference system without C12A7 and a mixture with 4 wt% C12A7 in the cement phase was investigated using heat flow calorimetry, QXRD and pore solution measurements. In the reference system, a clear induction phase without reactions was observed at all three temperatures, whereas with C12A7, heat flow and reactions were observed at each temperature, as C12A7 was observed to dissolve instantly after water addition accompanied by C2AH8 precipitation. Saturation indices of C2AH8 are slightly higher with the addition of C12A7, which indicates a higher supersaturation of C2AH8 and explains the measured precipitation before the actual CAC main reaction.
CRIS-Team Scopus Importer:2022-09-30
Keywords: Acceleration; Calcium aluminate cement; Calorimetry; Hydration; Pore solution; Temperature; X-ray diffraction

How does Citizen Science matter for policy? Analyzing the impact of citizen science in policy making - Almomani, Abeer; Awai, Erdoo Paula; Bonn, Aletta; de Barros, Ingrid Almeida; Friedly, Colleen; Gharesifard, Mohammad; Hecker, Susanne; Kartika, Erlinda Cahya; Kraft, Anne; Matthus, Elsa; Peter, Maria; Raja Schoob, Nussaibah Begum; et al. (iDiv Annual Conference 2019, 2019)
Citizen Science has been proven to support policy making (Bio Innovation Service, 2018),yet harnessing the full potential of Citizen Science requires further understanding of the particular areas of the policy development process where different Citizen Science projects have contributed. Using the policy cycle framework (Howlett&Ramesh, 2003) we assessed 500 Citizen Science projects reported in EU inventory and conducted in-depth analysis of 25 case studies. Our study aims to determine the impact of citizen science projects on the policy cycle.<br

How does sea level correlate with sea-water chemistry? A progress report from the Ordovician and Silurian - Munnecke, Axel; Calner, Michael; Harper, David A.T. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2010)
Keywords: Sea-water chemistry; Ordovician; Silurian

How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers - Lair, G. J.; Zehetner, F.; Fiebig, M.; Gerzabek, M. H.; Van Gestel, C. A. M.; Hein, Thomas; Hohensinner, Severin; Hsu, P.; Jones, K. C.; Jordan, G.; Koelmans, A. A.; Poot, A.; et al. (Environmental Pollution, 2009)

How electron flow controls contaminant dynamics - Borch, Thomas; Campbell, Kate; Kretzschmar, Ruben; Voegelin, Andreas; Ginder-Vogel, Matthew; Totsche, Kai Uwe; Barth, Johannes (Environmental Science & Technology, 2010)

How fluid-mediated rock transformations can mimic hydro-fracturing patterns in hydrothermal dolomite - Centrella, Stephen; Beaudoin, Nicolas E.; Köhn, Daniel; Motte, Geoffrey; Hoareau, Guilhem; Callot, Jean Paul (Marine and Petroleum Geology, 2022)
Numerous studies of hydrothermal dolomite bodies describe brecciated rocks characterized by dark angular fragments of dolomicrite bounded together by saddle dolomite crystals forming veins. Often associated with ore deposits, these hydrothermal dolomite breccia (HDB) patterns are usually interpreted as related to hydro-fracturing and so are considered as univocal markers of fluid overpressure. In this contribution we report an occurrence of typical HDB pattern in a dolomitized sedimentary breccia related to Mesozoic hyper-extension located in the Northern Pyrenees (France). We propose a model that accounts for the textural and crystallographic patterns of a HDB, without any fluid overpressure. The following observations lead us to propose that this HDB results from texturally controlled, hydrothermal fluid-initiated recrystallization of the initial sedimentary breccia by grain boundary migration: (1) the occurrence of rough contacts between the dolomite crystals and an initial dolomitized sedimentary breccia structure; (2) the crystallographic pattern of the hydrothermal dolomite; (3) the different grain size distribution in HDB texture and initial breccia structure; (4) the spatial distribution of oxide particles. Our alternate interpretation was further tested by 2D numerical simulations of the replacement process using the ‘ELLE’ modelling toolbox. Simulations confirm that advection of hot fluids along porous zones can locally trigger recrystallization by grain boundary migration, a replacement of the initial breccia texture and a preservation of larger, less permeable and cold fragments. We propose key features in textural evidence to assess whether HDB texture is pinpointing towards episodes of fluid overpressure and fracturing in carbonates, or if it rather is related to fluid-mediated rock recrystallization.
CRIS-Team Scopus Importer:2022-04-15
Keywords: Breccia; Dolomite; Hydrothermal; Modelling; Recrystallization

How to differentiate facilitation and environmentally driven co-existence - Steinbauer, Manuel; Beierkuhnlein, Carl; Khan, Mohammed A. S. Arfin; Harter, David E. V.; Irl, Severin D. H.; Jentsch, Anke; Schweiger, Andreas H.; Svenning, Jens-Christian; Dengler, Jurgen (Journal of Vegetation Science, 2016)
Positive plant–plant interactions (i.e. facilitation) receive increasing attention as a potentially important driver of community assembly. We conducted a systematic literature review indicating broad support for positive effects of potential facilitator species. However, a large majority of the reviewed studies (83% for field studies, 57% for experiments) share a similar risk of misinterpretation as they assess facilitative effects by comparing plots inhabited by a potential facilitator with randomly placed control plots nearby (paired sampling). As the distribution of facilitator species may itself be environmentally driven, species co-existence caused by facilitation cannot exclusively be separated from environmental effects (habitat sharing). Based on simulated plant communities and sampling protocols, we show how non-random co-existence can occur in the absence of facilitation. This is relevant because both the effect of spatial environmental heterogeneity and of facilitation (stress-gradient hypothesis) are expected to increase with environmental harshness. Nevertheless, 58% of facilitation studies neither undertook measures to minimize potential biases in their sampling approaches nor did they acknowledge such limitations in the discussion. Attention to this problem has significantly decreased in recent years. We propose that facilitation studies could be improved by (1) using random sampling for association studies, (2) co-analysing environmental factors, or (3) experimentally establishing presumed facilitators. Experimental approaches mimicking facilitative plant characteristics can help to identify facilitation mechanisms. Combining approaches and including functional traits of the involved species should further strengthen inference.
Keywords: Correlation; Cushion plant; Environmental favourability; Harsh environment; Interspecific; Mutualism; Plant–plant interaction; Positive interaction; Simulation; Spatial pattern; Species richness; Statistical inference

How to identify oceanic crust—Evidence for a complex break-up in the Mozambique Channel, off East Africa - Klimke, Jennifer; Franke, Dieter; Gaedicke, Christoph; Schreckenberger, Bernd; Schnabel, Michael; Stollhofen, Harald; Rose, Jens; Chaheire, Mohamed (Tectonophysics, 2016)
The identification of oceanic crust at riftedmargins plays a crucial role in academic research understanding rifting mechanisms and the architecture of continent–ocean boundaries, and is also important for hydrocarbon exploration extending into deeperwater. In this paper,we provide aworkflow for the determination of the crustal nature in the Mozambique Channel, east of Davie Ridge, by presenting a compilation of several geophysical attributes of oceanic crust at divergent margins. Previous reconstructions locate the Davie Ridge at the trace of a transform fault, along which Madagascar drifted to the south during the breakup of Gondwana. This implies a sharp transition from continental to oceanic crust seaward of Davie Ridge. Using newmultichannel seismic profiles offshore northernMozambique, we are able to identify distinct portions of stretched basement east of Davie Ridge. Two phases of deformation affecting the basement are observed, with the initial phase resulting in the formation of rotated fault blocks bounded by listric faults. Half-grabens are filled with wedge-shaped, syn-extensional sediments overlain by a prominent unconformity that northward merges with the top of highly reflective, mildly deformed basement, interpreted as oceanic crust. The second phase of deformation is associated with wrench faulting and probably correlates with the southward drift of Madagascar,which implies that the preceding phase affected basement generated ormodified prior to the opening of the West Somali Basin. We conclude that the basement is unlikely to consist of normal oceanic crust and suggest that the first extensional phase corresponds to rifting betweenMadagascar and Africa.We find evidence for a wide area affected by strike–slip deformation, in contrast to the earlier proposed major single transform fault in the vicinity of Davie Ridge and suggest that the Mozambique Channel area to the north of Madagascar may be classified as an oblique rather than sheared margin.
Keywords: Davie Ridge; Mozambique Channel; Oblique margin; Oceanic crust; Reflection seismic data; Rifting

How to increase the hydration degree of CA - The influence of CA particle fineness - Klaus, Sebastian; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2015)
The reaction of a sample with mainly coarse particles of CA (d(50) = 50 mu m) is characterized by a low hydration rate and only 34 rel.-% of CA dissolved after 22 h. Whereas in a very fine CA-sample (d(50) = 4 mu m) hydration starts delayed but then shows the highest hydration rate and a dissolution of 62 rel.-% CA. The behaviour is explained by the coverage of CA-particles with a dense hydrate layer of C(2)AH(x) and AH(x). This reacted CA-rim is supposed to have the same thickness for different sized CA-particles. Optimization of Gauss distribution curves, which were applied to simulate a more realistic particle size distribution, leads to a reacted rim thickness of 1.3 mu m until reaction is stopped. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords: Hydration (A); Calorimetry (A); Reaction (A); X-ray diffraction (B); Calcium aluminate cement (D)

Hybrid mafic dykes from Delwara Shear Zone, Mt. Abu, NW India - Pandit, Manoj K.; Dotzler, Ramona; de Wall, Helga (Journal of the Geological Society of India, 2016)
Keywords: Delwara Shear Zone; Geochemistry; Hybridization; Mafic dykes; Mixing line calculation; Mt. Abu; Rajasthan

Hydration enthalpy of amorphous tricalcium phosphate resulting from partially amorphization of β-tricalcium phosphate - Hurle, Katrin; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (BioNanoMaterials, 2017)
Calcium phosphate cements (CPCs) are applied as bone cements due to their excellent biocompatibility. In the present study, the quantitative phase content development during hydration of partially amorphized β-tricalcium phosphate (β-TCP) within the first 24 h was investigated by in-situ X-ray diffraction (XRD) combined with the G-factor method, an external standard method. The quantity of amorphous phase (ATCP) in the powders was determined by the G-factor method. The hydration model established for partially amorphized β-TCP indicates that ATCP reacted first, followed by the hydration of a small fraction of crystalline β-TCP starting after some h. Consequently, hydration resulted in biphasic samples composed of calcium deficient hydroxyapatite (CDHA) and crystalline β-TCP. The ratio wt%(CDHA)/wt%(β-TCP) after 24 h hydration was adjustable by the initial ATCP content. The crystallinity of CDHA was nearly independent of the ATCP content. Since the biological degradability of CDHA and β-TCP differ, the degradation performance of the set cements is expected to be adjustable by varying the ATCP content. The present study provided a basic understanding of the hydration mechanism of partially amorphized β-TCP, which is the prerequisite for the development of applicable CPC formulations. Statement of Significance Calcium phosphate cements (CPCs) are medically applied for bone repair due to their excellent biocompatibility. β-Tricalcium phosphate (β-TCP), which is hardly reactive in water in its crystalline state, was previously shown to be activatable by partial amorphization. This provides potential for the development of new CPCs setting to biphasic samples composed of β-TCP and calcium deficient hydroxyapatite (CDHA). The degradation performance of these cements is expected to be adjustable by varying the ratio of CDHA to β-TCP. In the present study, the so far unknown setting mechanism of partially amorphized β-TCP was investigated in detail. The results contribute to the basic understanding of the hydration of partially amorphized β-TCP, which is important for the targeted development of new cement formulations.<br
Keywords: Amorphized TCP; bone cement; isothermal calorimetry; quantitative X-ray diffraction; thermodynamic calculations

Hydration in the ternary system calcium sulfoaluminate - ordinary Portland cement - calcium sulfate: Kinetics, mechanisms, performance and the impact of Li2CO3 addition - Wolf, Julian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2021)
CSA-OPC-C blends are used for applications where rapid setting and drying is desired. The hydration process is complex due to the multitude of involved phases, metastability issues and amorphous nature of hydrates. Overall little research concerning the early hydration kinetics in such blends has been published and this thesis aims to contribute towards a further understanding of these systems. By means of predominantly XRD, pore solution analysis and thermodynamic calculations, a basic hydration scheme is developed. Based on thermodynamic modeling five different ternary blends are chosen for further investigation. The hydration process is documented from the point of mixing up to 28 d. It was found that the hydration process can be divided in two main periods. The early period is characterized by the rapid dissolution of ye’elimite and Ca-sulfate, resulting in the formation of ettringite and amorphous aluminum hydroxide. During this period low pH values prevail, with high Al and S concentrations and low Ca concentrations in the pore solution. Contrary to predominant literature reports, alite can in fact react to significant degree under these conditions. The early C3S dissolution kinetics were found to depend on the availability of reactive calcium sulfate. This early C3S reaction directly contributes to the precipitation of ettringite. An amorphous silicon bearing hydrate of unknown nature must form at this early stage. With increasing pH values in the liquid phase and either the enrichment or depletion of Al in the pore solution, a second state is initiated. The initially formed silicon bearing hydrate and amorphous aluminum hydroxide are destabilized and either C-S-H precipitation or straetlingite crystallization ensues. Upon C-S-H formation the alite reaction rate is significantly increased and the kinetics resemble the main C3S reaction in OPC systems. For the systems poor in anhydrite high oversaturations with respect to straetlingite are observed in this second stage. These translate to high potential crystallization pressures. It was found that the late crystallization of straetlingite results in potential tensile stresses exceeding the tensile strength of the material, resulting in a higher fraction of capillary pores, and decreased mechanical performance. The addition of Li2CO3 results in accelerated dissolution of ye’elimite and alite and increased precipitation of ettringite. Significantly reduced ye’elimite dissolution rates are observed when exceeding a critical dosage of Li2CO3. This results in an earlier transition towards the C-S-H forming stage in the respective blend. <br

Hydration kinetics of CA2 and CA - Investigations performed on a synthetic calcium aluminate cement - Klaus, Sebastian; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2013)
Much is already known about the hydration of monocalcium aluminate (CA) in calcium aluminate cements (CACs). CA2 is known to be weakly hydraulic. Therefore, the hydration kinetics of CA2 were not of as great interest as those of the hydration of CAC. We were able to show that the hydration of CA2 begins as soon as the hydration rate of CA has reached its maximum and the first precipitation of C2AH8 has started. The hydration of different CA/CA2 ratios was analyzed by the G-factor quantification. The individual contributions of the phases CA and CA2 to the heat flow were calculated based on the amounts dissolved by applying thermodynamic data. The heat flow as calculated from XRD data was then compared with the measured heat flow. It obtained a good consistency between the two. The very pronounced influence of CA2 during hydration of CAC can be clearly demonstrated. © 2012 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LM.hydrat
Keywords: Calcium aluminate cement (D); Calorimetry (A); Hydration (A); Reaction (A); X-ray diffraction (B)

Hydration kinetics of calcium aluminate cement in presence of Li2CO3 - Götz-Neunhoeffer, Friedlinde (Proceedings of the Centenary Conference 2008,, 2008)
UnivIS-Import:2015-04-16:Pub.2008.nat.dgeo.IGM.LM.hydrat_9

Hydration kinetics of tricalcium silicate: A dataset for reaction rate calculations and nanoscale analysis employing atom probe tomography - Naber, Christoph (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2019)
The hydration of tricalcium silicate (C3S) is a dissolution precipitation process. The dissolution of C3S delivers ions to the pore solution and the hydration products Calcium-Silicate-Hydrate (C-S-H) and portlandite (CH) consume said ions by precipitating from the pore solution. The underlying kinetics of the coupled reaction are to this day not fully understood. This thesis presents efforts to investigate the C3S - water interface at the nanoscale and a comprehensive dataset to calculate individual C3S dissolution rates and C-S-H precipitation rates during hydration. The C3S - water interface is investigated in this work by atom probe tomography (APT), an imaging technique with three-dimensional nanoscale resolution and chemical identification. In order to obtain samples suitable for APT, a method to synthesize large monocrystalline C3S grains is presented. The synthesis is conducted in an optical floating zone furnace by annealing polycrystalline rods at temperatures just below the melting point of C3S. Large monocrystalline grains (>500 µm) of monoclinic and triclinic polymorphs of C3S could be synthesized. The atom probe tomography experiments conducted with the thus produced samples demonstrate that it is possible to measure tricalcium silicate with this method by carefully adjusting the measurement parameters. Furthermore it could be shown that the sample preparation and measurement conditions employed are harmful to the hydrate phase C-S-H and thus also to potential metastable reaction products forming at the C3S - water interface. These harmful conditions might be avoided by applying a novel sample preparation procedure at cryo conditions. The presented comprehensive dataset contains data for the first 24 hours of hydration of triclinic and monoclinc C3S samples at different water to solid ratios. The measured parameters include XRD and NMR phase contents, pore solution concentrations, specific surface areas, and SEM images at various time steps. With this dataset, it is possible to calculate theoretical C3S dissolution and C-S-H precipitation rates by combination with interfacial dissolution and precipitation rates determined separately. The results show a good fit between the theoretical C-S-H precipitation rates and the actual reaction rates measured for both C3S polymorphs and all investigated water to solid ratios indicating that the applied calculation model incorporates all relevant factors to describe C-S-H precipitation kinetics during C3S hydration. The theoretical C3S dissolution rates in contrast do not fit the actual reaction rates in all investigated systems. This demonstrates that there are important factors missing in the applied calculation model for C3S dissolution kinetics.
Keywords: Calcium-Silicate-Hydrate (C-S-H); Cement; Hydration; Kinetics; Tricalcium silicate

Hydration mechanism of a calcium phosphate cement modified with phytic acid - Hurle, Katrin; Weichhold, Jan; Brueckner, Manuel; Gbureck, Uwe; Brueckner, Theresa; Götz-Neunhoeffer, Friedlinde (Acta Biomaterialia, 2018)
Calcium phosphate cements composed of β-tricalcium phosphate (β-TCP) and phosphoric acid were modified by addition of 5, 10, 12.5, 15 and 20 wt% phytic acid (IP6) related to the β-TCP content and compared to a reference containing 0.5 M citric acid monohydrate solution as setting regulator. The hydration reaction of these cements was investigated by isothermal calorimetry and in-situ X-ray diffraction at 23 °C and 37 °C. The cements were further characterized with respect to their injectability, rheology, zeta potential and time-resolved compressive strength development. Injectability was strongly improved by IP6 addition, while the maximum effect was already reached by the addition of 5 wt% IP6. This could be clearly related to an increase of the negative zeta potential leading to a mutual repulsion of cement particles. A further increase of the IP6 content had a detrimental effect on initial paste viscosity and shifted the gelation point to earlier time points. IP6 was further proven to act as a retarder for the cement setting reaction, whereas the effect was stronger for higher IP6 concentrations. Additionally, IP6 favoured the formation of monetite instead of brushite and a better mechanical performance compared to the IP6 free reference cemen
Keywords: Calcium phosphate cement; Phytic acid; Rheology; In-situ XRD; Injectability

Hydration mechanism of partially amorphized β-tricalcium phosphate - Hurle, Katrin; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Acta Biomaterialia, 2017)
Calcium phosphate cements (CPCs) are applied as bone cements due to their excellent biocompatibility. In the present study, the quantitative phase content development during hydration of partially amorphized β-tricalcium phosphate (β-TCP) within the first 24 h was investigated by in-situ X-ray diffraction (XRD) combined with the G-factor method, an external standard method. The quantity of amorphous phase (ATCP) in the powders was determined by the G-factor method. The hydration model established for partially amorphized β-TCP indicates that ATCP reacted first, followed by the hydration of a small fraction of crystalline β-TCP starting after some h. Consequently, hydration resulted in biphasic samples composed of calcium deficient hydroxyapatite (CDHA) and crystalline β-TCP. The ratio wt%(CDHA)/wt%(β-TCP) after 24 h hydration was adjustable by the initial ATCP content. The crystallinity of CDHA was nearly independent of the ATCP content. Since the biological degradability of CDHA and β-TCP differ, the degradation performance of the set cements is expected to be adjustable by varying the ATCP content. The present study provided a basic understanding of the hydration mechanism of partially amorphized β-TCP, which is the prerequisite for the development of applicable CPC formulations.<br
Keywords: Amorphization; Bone cement; Crystallite sizes; Tricalcium phosphate; XRD quantification

Hydration of a 2-component CSA-OPC-mix – timing of component blending & setting on demand - Jakob, Cordula; Rudolph, Jennifer; Wolf, Julian Johannes; Neubauer, Jürgen (Advances in Cement Research, 2024)
With the ongoing development of new technologies like 3D printing, the requirements for the performance of cementitious materials become more complex. Setting on demand, while the workability of the material is retained until placement, is an important aspect of this usage. A ternary CSA-OPC-C system was developed to achieve setting on demand in a 2-component setup, where two retarded cementitious components were mixed after specific times of storage. The kinetics of the individual systems and the blend were examined by heat flow calorimetry, quantitative X-ray diffraction and pore water analysis. The rheological development was monitored by a penetration test method. The results show that the performance of the blend is independent of the storage time of the individual components and can be tailored by changes in the retarder dosage in the individual components. The initial reaction in the blend is characterized by the simultaneous dissolution of ye’elimite and C3S, resulting in the formation of ettringite as the sole detectable hydrate phase. The fate of silicon remains unclear as with the methodology at hand no silicon incorporating hydrate phase can be identified.
CRIS-Team Scopus Importer:2024-06-21
Keywords: 3D-printing Cement short-hand notation is used throughout where C = CaO; H = H; Cement/cementitious materials; Diffraction (X-ray; neutron; electron); Ettringite; Rheological/rheological properties

Hydration of C3S in presence of CA: Mineral-pore solution interaction - Nehring, Jörg; Jansen, Daniel; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Journal of the American Ceramic Society, 2018)
C 3 S and CA are the main phases of OPC and Fe-rich CAC, respectively. The objective of this research was to investigate the influence of CA on C 3 S hydration, representing an under sulfated OPC-rich binder, and to shed light on the underlying hydration mechanisms. To this end, C 3 S was blended with 1-30 wt-% CA and the pastes (w/c 0.5) were investigated by heat flow calorimetry, in situ X-ray diffraction and analysis of the pore solution chemistry. CA additions ≥5 wt-% reveal a separation into three distinct heat flow maxima, whereas additions ≤3 wt-% just retard the start of the main reaction. The silicate reaction (dissolution of C 3 S and precipitation of C–S–H with or without CH) can be retarded for 4 to ≥22 hours in comparison to pure C 3 S depending on the admixed CA content. The start of the silicate reaction seems to be related to a decrease in Al- and increase in Ca-concentration in the pore solution. However, it can be shown in this study that C 3 S is able to dissolve even at high Al concentrations in the pore solution.
CRIS-Team Scopus Importer:2019-05-02
Keywords: cements; hydration; calcium aluminate; calcium silicate; X-ray methods

Hydration of calcium aluminates at 60°C – Development paths of C2AHx in dependence on the content of free water - Hüller, Florian; Neubauer, Jürgen; Kaessner, Stefan; Götz-Neunhoeffer, Friedlinde (Journal of the American Ceramic Society, 2019)
The influence of water loss during the hydration of calcium aluminates on the phase development is investigated at 60°C. This is relevant for applications in which calcium aluminate cement (CAC) based formulations are exposed to quick drying during hydration. The presented results provide new insights into the well-known conversion processes occurring in CAC pastes. Using in situ XRD two different routes of the development of initially formed C2AH8 are determined: (a) transformation to C3AH6 + AH3 in the presence of sufficient free water and (b) dehydration to C2AH5 at a lack of free water. Moreover, the influence of precuring of the pastes at 23°C before heating to 60°C is investigated. The increasing loss of free water with increasing precuring time resulting from both, precipitation of hydrate phases and evaporation, causes incomplete hydration of CA or CA2 as well as dehydration of C2AH8 instead of conversion into C3AH6. Comparative investigations of sealed samples always revealed complete hydration of CA and CA2 as well as complete conversion of C2AH8.<br
Keywords: calcium aluminate cement; conversion; hydration; XRD

Hydration of Portland cement with high replacement by siliceous fly ash - Deschner, Florian; Winnefeld, Frank; Lothenbach, Barbara; Seufert, Sebastian; Schwesig, Peter; Dittrich, Sebastian; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2012)
The effects of two different low calcium fly ashes on the hydration of ordinary Portland cement (OPC) pastes containing 50 wt.% of fly ash were investigated over a hydration time of 550 days. The results were compared with a reference blend of OPC containing 50 wt.% of inert quartz powder allowing the distinction between "filler effect" and pozzolanic reaction. Until 2 days, no evidence of fly ash reaction was measured and its influence on the hydration is mainly related to the filler effect. From 7 days on, the effects of the pozzolanic reaction were observed by the consumption of portlandite, the change of the pore solution chemistry, the formation of a presumably water-rich inner hydration product and the change of the C-S-H composition towards higher Al/Si ratio compared to the C-S-H of neat OPC. Additional strength due to the pozzolanic reaction developed after 28 days of hydration. © 2012 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LM.hydrat
Keywords: Blended Cement (D); Filler (D); Fly ash (D); Hydration (A); Pozzolan (D)

Hydraulische Sodalithe - Kristallographie und Hydratation - Neubauer, Jürgen; Pöllmann, Herbert (European Journal of Mineralogy, 1992)
UnivIS-Import:2015-03-05:Pub.1992.nat.dgeo.IGM.LM.hydrau

Hydrocarbon-seep deposits in the lower Permian Angie Formation, Central Lhasa Block, Tibet - Liu, Chao; An, Xianyin; Algeo, Thomas J.; Munnecke, Axel; Zhang, Yujie; Zhu, Tongxing (Gondwana Research, 2021)
Methane seepage along continental margins has been linked to climatic warming, yet it is uncertain whether such seepage took place during the Permian, a period that witnessed a transition from an icehouse to a greenhouse world. To address this issue, we investigated calcareous concretions and layers within mudstones/shales of the Kungurian Angie Formation in the Xainza area, central Tibet. A combination of petrographic, mineralogical, elemental, and carbon‑sulfur isotopic analyses provide strong evidence for a hydrocarbon-seep origin of these carbonates, with thermogenic methane and crude oil being the most likely carbon sources. Our dataset also indicates that, although fueled by a common deep-buried hydrocarbon reservoir, these layers and concretions experienced different biogeochemical processes due to variable rates of cold-seep fluid flux combined with persistently low sulfate concentrations in bottom waters of the Bangong-Nujiang Tethyan Ocean. A biogeochemical switch from sulfate-dependent to iron oxide-coupled anaerobic oxidation of methane in the sulfate-methane transition zone, likely triggered by sulfate exhaustion, was inferred to affect carbonate layer formation near the sediment-water interface. If true, this switch, together with common vent structures, would have resulted in escape of large amounts of methane directly to the ocean-atmosphere system. The hydrocarbon seeps in the central Lhasa Block was approximately coeval with rapid climate warming in the peri-Gondwanan region during the early Kungurian. Although further investigations are required in the future, this study demonstrates a possible causal relationship between regional tectonic evolution, hydrocarbon seepage, and global climate change.
CRIS-Team Scopus Importer:2020-12-25
Keywords: AOM; Cold seep; Greenhouse; Kungurian; Stable isotopes

Hydrochemical and Isotopic Features of the Khaung Daing Hot Spring (Inle lake, Southern Shan State, Myanmar). - Sacchi, Elisa; Re, Viviana; Setti, Massimo; Thin, Myat Mon; Di Sipio, Eloisa (Procedia Earth and Planetary Science, 2017)
The Inle lake watershed develops along a right-lateral strike-slip fault running parallel to the Sangaing fault, a major continental transform fault between the India and Sunda Plates. Located on the northwestern border of the Inle lake basin, the Khaung Daing hot spring outflows at a temperature of about 70°C. This contribution represents a reconnaissance study of the spring and describes its main hydrochemical and isotopic features, compared to surface and ground waters in the watershed. The water pH is slightly acidic, and, compared to the other water samples from the watershed, shows an EC in the high range (57-1284 μS/cm), the lowest pH and Eh values, and is Na-HCO3, whereas surface and ground waters are Ca(Mg)-HCO3 type. The hot spring isotopic composition falls close to the Yangon Meteoric Water Line, indicating that, despite its temperature, it is not strongly modified by water-rock interaction processes. Preliminary results suggest that this hydrothermal water is likely related to deep meteoric and ground water circulation within a fault zone, in a region characterized by an elevated geothermal gradient.
Keywords: groundwater; stable isotopes; hydrothermal waters; mineralogy

Hydrochemical and isotopic tracing of runoff generation in the small mountainous catchment Uhlířská (Czech Republic), using the netpath approach - Vitvar, Tomas; Sanda, Martin; Marx, Anne; Hubert, E.; Jancovec, J; Barth, Johannes (Acta Hydrologica Slovaca, 2016)

Hydrogeological investigation of shallow aquifers in an arid data-scarce coastal region (El Daba’a, northwestern Egypt) - Yousif, Mohamed; van Geldern, Robert; Bubenzer, Olaf (Hydrogeology Journal, 2016)
Keywords: Climate change; Coastal aquifers; Egypt; Geographic information systems; Stable isotopes

Hydrogeologie unter einem D-A-CH - Grathwohl, Peter; Kozel, Ronald; Zetinigg, Hilmar; Liedl, Rudolf; Barth, Johannes (Grundwasser, 2010)

Hydrogeomorphology and recharge mechanism of a coastal aquifer in tectonic-controlled watersheds: A multi-proxy approach based on remote sensing and environmental isotopes - Yousif, Mohamed; van Geldern, Robert; Bubenzer, Olaf (Groundwater for Sustainable Development, 2024)
Coastal aquifers worldwide can be considered an essential water source required for preservation of the coastal ecosystems. However, these aquifers are vulnerable to seawater intrusions and over-pumping due to their proximity to the sea and human activities, respectively. Therefore, the investigation of recharge mechanism has special importance in the regions of tectonic rift activities where they exhibit complex geological structures and hydrogeological characteristics. In the current research, an integrated approach of remote sensing and environmental isotopes together with field investigation and subsurface datasets (aeromagnetic, gravity and well logs) are employed to identify the nature and factors affecting groundwater recharge of the Miocene coastal aquifer along the Red Sea-Gulf of Suez western margin (continental rift basin). The research findings reveal that: (1) The coastal Miocene aquifer consists of both clastic (sandstone, sand and gravels) and carbonate rocks (limestone and dolomite) with subsurface thickness ranges between 100 and 200 m. (2) Its groundwater shows contrast salinity values (expressed by total dissolved solids, TDS) between 2755 and 10,996 mg/l, due to the variation in recharge rates and the lithologic dissimilarity of the water bearing formations. (3) The environmental isotopes indicate that the Miocene groundwater has a mixed isotopic signature between modern meteoric (rainfall) and fossil waters. (4) The isotopic data of the Miocene aquifer and the enriched Gulf of Suez verifies that no seawater intrusions are affecting this aquifer with existing hydraulic barriers (clogged/sealed faults or impermeable massive blocks). (5) The hydrogeomorphological investigations, aeromagnetic and gravity data reveal an existence of two morphotectonic depressions (water collectors) which have paleo and recent recharge opportunities for the subsurface sedimentary layers (2–4 km thick). From the applied viewpoint, these two depressions have potential prospects for future groundwater exploration, which has significant impact on food security and land reclamation.
CRIS-Team Scopus Importer:2024-06-21
Keywords: Environmental isotopes; Groundwater; Miocene aquifer; Red sea coast; Remote sensing

Hydrothermal activity and associated subsurface processes at Niuatahi rear-arc volcano, North East Lau Basin, SW Pacific: Implications from trace elements and stable isotope systematics in vent fluids - Klose, Lukas; Kleint, Charlotte; Bach, Wolfgang; Diehl, Alexander; Wilckens, Frederike; Peters, Christian; Strauss, Harald; Haase, Karsten; Koschinsky, Andrea (Geochimica Et Cosmochimica Acta, 2022)
Hydrothermal activity is abundant in the area between the North Eastern Lau Spreading Center and the Tofua intra-oceanic island arc with multiple active sites in the rear-arc at the Mata and Niuatahi volcanoes. We report geochemical data for high-temperature vent fluids sampled from within the caldera of Niuatahi volcano. Hydrothermal fluids were sampled from three vent sites: South Central, Southwestern Cone and Northern Cone located in water depths between 1607 and 1699 m. Maximum temperatures of 334 °C were measured and pH values were as low as 2.8. The vent fluids were characterized by depletions in Mg, SO4 and U as well as an enrichment of (trace) metals (e.g., Fe, Mn, K, Li) and dissolved gases (e.g., H2S, CO2, H2) relative to seawater. Water-rock ratios calculated based on concentrations (K, Li, Rb, Cs, REE) and isotope ratios (δ7Li, δ11B, 87Sr/86Sr) suggest fluid-rock interactions under rock-dominated conditions at all three vent sites. The South Central vents lie closest to the site of most recent volcanic activity in the Niuatahi caldera. Vent fluids are characterized by relatively low Cl concentrations (as low as 292 mmol/kg) that are indicative of sub-critical phase separation. These fluids also had the lowest pH values (2.8–3.1), highest H2S and lowest H2, CH4 and CO2 concentrations of the three sites. The δD and δ18O values suggest that H2O and CO2 were added in small amounts by subduction-related volcanic vapors. However, there was no evidence for magmatic SO2 input in the vent fluids at the time of sampling in 2018. Vent fluids from the Northern and Southwestern Cone sites on the caldera ring fault had a similar chemical composition, despite being situated at opposite sides of the caldera. Fluids from these sites had lower Fe/Mn ratios (<1) and H2S concentrations than those from South Central suggesting that they were affected by subsurface cooling and sulfide precipitation. This study indicates variations of the Niuatahi hydrothermal vent sites depending on the location within the caldera with variable effects of fluid-rock interaction and magmatic input on fluid compositions in agreement with previous work on fluid S isotopes and sulfides.
CRIS-Team Scopus Importer:2022-07-15
Keywords: Caldera volcano; Hydrothermal activity; Phase separation; Temporal variability; Water–rock interaction

Hydrothermal alteration and fluid pH in alkaline-hosted epithermal systems - Smith, Daniel J.; Naden, Jonathan; Jenkin, Gawen R. T.; Keith, Manuel (Ore Geology Reviews, 2017)
Epithermal gold mineralisation is found in a wide compositional range of host lithologies, but despite the diversity the alteration mineral assemblages are often similar between deposits. Notable exceptions are those gold deposits hosted in alkaline host rocks. Alkaline-hosted epithermal deposits are rare, but important, as they include some of the world's largest known epithermal deposits by contained metal (e.g. Ladolam, Cripple Creek, Porgera). As well as the exceptional gold contents, the alkaline-hosted systems tend to exhibit different alteration mineral assemblages, with less quartz and widespread silicification than sub-alkaline-hosted equivalents, and greater enrichments in tellurium, and a scarcity of acid alteration (advanced argillic) types. In this study, geochemical modelling is used to demonstrate that 300 °C hydrothermal fluids in equilibrium with alkali, silica-undersaturated host rocks at low water/rock ratios reach significantly higher pH than equivalents in sub-alkaline lithologies. A maximum, near-neutral pH (5.5–6) is buffered by reactions involving quartz in silica-saturated alkaline and calc-alkaline lithologies. In silica-undersaturated, alkaline host rocks, quartz is exhausted by progressive water-rock interaction, and pH increases to 7 and above. Both tellurium and gold solubility are favoured by high fluid pH, and thus there is a clear mechanism within these hydrothermal systems that can lead to effective transport and concentration to produce gold telluride ore deposits in alkaline igneous hosts. This modelling demonstrates that alkaline rocks can still be altered to advanced argillic assemblages; the paucity of this alteration type in alkaline hosts instead points to NaCl ≫ HCl in magmatic volatile phases at the initiation of hydrothermal alteration.
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Hydrothermal controls on iron and lead mineralization on the farms Leeuwbosch and Cornwall, Thabazimbi District, South Africa - Moeller, V.; Klemd, Reiner; Joachimski, Michael; Barton, J. M. (Ore Geology Reviews, 2014)
The Paleoproterozoic Malmani Subgroup and Penge Formation (Transvaal Supergroup) exposed on the farms Leeuwbosch and Cornwall north of Thabazimbi (Limpopo Province, South Africa) host hydrothermal Pb-Ag-Cu-Zn and high-grade hematite iron ore deposits which include the historic Leeuwbosch lead mine. Based on ore petrography, fluid inclusion and stable isotope analyses and geochemical modeling, the structurally controlled, stratabound Leeuwbosch Pb-Ag-Cu-Zn-Fe deposits formed from high salinity NaCl-CaCl2-rich basinal brines with total salinities from 18 to 24wt.% NaCl equivalent which are similar to those found in the Mississippi Valley Type (MVT) Pb-Zn deposits. The minimum formation temperatures (homogenization temperatures) for the lead deposits range between 120 and 185°C and the estimated formation conditions are 200°C at 1kbar pressure. Stable isotope analyses of gangue siderite and calcite indicate that the deposits formed from base metal-enriched brines derived from recycled seawater with δ13Cvs. PDB from 0.46 to 3.17‰ and δ18Ovs. SMOW from -2.95 to -1.79‰. Hydrothermal transport of lead and silver as PbCl3 - and AgCl2 - respectively took place at mildly acidic pH and elevated fO2 in the SO4 2- predominance field. Extensive host rock interaction neutralized and reduced the ore fluid to precipitate galena hosting Ag with chalcopyrite and sphalerite. Fluid inclusions in gangue quartz and calcite in the extensive structurally controlled and pervasive stratabound hydrothermal iron ore deposits on the farms Leeuwbosch and Cornwall, chiefly consisting of high-grade hematite with rare relict magnetite, show a wide compositional variability due to episodic fluid mixing and successive hydrothermal activity in the presence of several distinct fluid end members. Total salinities of fluid inclusions in quartz from the hematite deposits range from 9.2 to 39.9wt.% NaCl eq. with highly variable proportions of NaCl and CaCl2 and minimum formation temperatures are between 100 and 190°C. The estimated formation conditions for the iron ore deposits are 175°C and 1kbar. Stable isotopes of gangue calcite indicate that diagenetic fluids with δ13Cvs. PDB from -3.33 to -2.09 and δ18Ovs. SMOW from 2.52 to 5.60‰ and a second fluid with δ13Cvs. PDB of -7.45 and δ13Cvs. PDB of 17.45 were controlling the formation of the hematite deposits. In agreement with oxidized conditions during hematite formation and characteristic host rock alteration patterns traced by carbon and oxygen isotopes, the second low salinity fluid was derived from the overlying Waterberg Group sandstones and played an important role in the formation of the iron ore deposits, in addition to high salinity diagenetic brines. Iron was leached from the BIFs of the Penge Formation, transported as FeCl+ under mildly acidic conditions and likely deposited in response to the oxidation of the iron-bearing fluids. The lead and iron ore deposits formed by combinations of structural controls which influenced the regional fluid flow patterns and fluid compositions, and fluid-rock interaction with reactive carbonate lithologies of the Malmani Subgroup which acted as a sink for metals transported in acidic hydrothermal solutions. © 2014 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LG.hydrot
Keywords: Fluid inclusions; Galena; Hematite; Leeuwbosch; Stable isotopes; Thabazimbi

Hydrothermal mineralization of celadonite: Hybridized fluid-basalt interaction in Janggi, Korea - Park, Jongkyu; Lim, Hoseong; Myeong, Bora; Jang, Yun-Deuk (American Mineralogist, 2022)
The origin of celadonite still remains enigmatic and fragmentary. Exceptional celadonite mineralization was discovered in the Miocene lacustrine Janggi Basin in the southeastern Korean Peninsula. This Janggi celadonite is a greenish, earthy/vitreous material filling east-west trending fault zones in basaltic flows. The scale of the celadonite body is up to a meter thick and laterally extends 10 m. These occurrences are markedly in contrast with celadonite as vesicle-filling or mineral-replacing types in the literature. The Janggi celadonite allows exploring the puzzling genesis of celadonite and comparing its characteristics with global cases for a better understanding of celadonite formation. X-ray difraction and microprobe analyses demonstrate that the Janggi celadonite ranges from ferroceladonite through celadonite to ferroaluminoceladonite and is mixed with opal at a ratio of up to 3:7. Detailed fieldwork and whole-rock major, trace, and oxygen isotope analyses indicate that celadonite is formed in an open system at 120 °C by the interaction of hybridized fluid (a mixture of <55% magmatic and >45% other origins) and basalts during the physicochemical fault brecciation of the host rock. The cations needed for celadonite formation were supplied from the smectitization/zeolitization of rhyolitic mesostasis (for Al and part of K) and pyroxene microlites (for Fe and Mg) in the basaltic breccias during the associated oxidation of micro-nanoparticles by circulating fluids (for most of K). A comparison of the Janggi celadonite with global cases highlights that celadonite genesis is neither limited to the seawater alteration of basalt nor do hosts and reactive fluids control celadonite compositions. A contextualized perspective on celadonite genesis alludes that a potassic alteration of rock that is rich in ferromagnesian components in a shallow crustal environment (< 200 MPa at < 450 °C) produces celadonite. Because of the relative availability of the necessary components for celadonite precipitation, our model predicts celadonite mineralization in many volcanic environments, where magmatic fluid and particle size reduction could contribute. These insights emphasize celadonite's potential applications for tracing geothermal history.
CRIS-Team Scopus Importer:2022-06-17
Keywords: Celadonites; fault brecciation; fluid-rock interaction; hydrothermal mineralization; oxygen isotope

Hydrothermal origin of Devonain conical mounds (kess-kess) of Hamar Laghdad Ridge, Anti-Atlas, Morocco. Comment. - Joachimski, Michael; Buggisch, Werner (Geology, 1999)
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LG.hydrot

Hydrothermal synthesis of 11 Å tobermorite – Effect of adding metakaolin to the basic compound - Schreiner, Jürgen; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Jansen, Daniel (Applied Clay Science, 2020)
Different amounts and types of metakaolin were analyzed and applied for the hydrothermal synthesis of 11 Å tobermorite. All synthesized samples were investigated by means of powder XRD combined with Rietveld refinement. Al-substituted 11 Å tobermorite was successfully synthesized on the basis of a broad range of compounds characterized by a varying content of metakaolin. Katoite was present depending on the amount of supplied Al3+, which was determined by the dosage of metakaolin. Minor crystalline components included in the two types of metakaolin sources varied greatly in their reactivity under hydrothermal conditions. Despite a different degree of purity, the two types of metakaolin showed corresponding effects at moderate dosages but contrary effects at higher dosages as for the synthesis of 11 Å tobermorite. The domain morphology of tobermorite could be associated with Al3+ incorporation for low dosages of metakaolin represented by up to 2 wt.- % Al2O3 in the dry mix. By contrast, Al3+ affected tobermorite lattice parameters at equivalent and even at higher dosages with c reaching 22.95 Å at 12 wt.-% Al2O3 in the dry mix.<br
CRIS-Team Scopus Importer:2020-01-14
Keywords: Hydrothermal synthesis; 11 Å tobermorite; Metakaolin; Powder diffraction; Katoite

Hygrothermal stability of ettringite in blended systems with CAC-OPC-CŠ - Noor, Lamiya; Rost, Pauline; Kirchberger, Irina; Götz-Neunhoeffer, Friedlinde; Ideker, Jason H. (Cement and Concrete Research, 2024)
The hygrothermal stability of ettringite in cementitious systems composed of calcium aluminate cement (CAC) blended with ordinary portland cement (OPC) and calcium sulfate (CŠ) has been investigated for five simulated environmental conditions- i) 23 °C-100% RH (Relative Humidity), ii) 23 °C-50% RH, iii) 38 °C-50% RH, iv) 50 °C-50% RH, and v) 60 °C-50% RH. Two types of ternary systems were used, one rich in CAC (with a higher mass ratio of CAC compared to OPC) and the other rich in OPC (with a higher mass ratio of OPC compared to CAC), both with a water-to-cement (w/c) ratio of 0.35. The volume change and mechanical properties were evaluated by dimensional change, mass change, compressive strength, and flexural strength measurements. Hydration and microstructural properties were evaluated by isothermal calorimetry, thermogravimetric analysis (TGA), and Quantitative X-Ray Diffraction (QXRD) via the G-factor method. QXRD results showed that the studied CAC-rich binder formed 26.0 ± 1 wt% and the OPC-rich binder 28.9 ± 1 wt% ettringite after 24 h of hydration. However, with the increase in temperature, decrease in relative humidity, and time of exposure, the OPC-rich binder showed higher shrinkage, higher mass loss, and a significant decrease in ettringite content compared to the CAC-rich binder.
CRIS-Team Scopus Importer:2024-07-12
Keywords: Calcium aluminate cement; Ettringite; Hygrothermal properties; Portland cement; Ternary binders

Hypercalcified inozoan sponges from the Norian reef carbonates of Turkey - Senowbari-Daryan, Baba; Link, Michael (Revue de Paléobiologie, 2016)
Hypercalcified sponges, including the chambered “Sphinctozoans”, un-chambered “Inozoans”, chaetetids and spongiomorphid-like representatives are the most abundant reef builders in Norian reef boulders from several localities in the Taurus Mountains, southern Turkey. Numerous samples, containing hypercalcified sponges and other reef organisms were collected from these reef boulders in the Dereköy basinal sediments exposed west of Antalya and Kasımlar Basin deposits, north of Antalya. The inozoan fauna of these boulders are described in this paper. 31 species (18 new), belonging to 18 genera (5 new) and 7 families were recognized. Following genera and species are described as new: Preperonidella asymmetrica nov. sp., Milysa polysiphonata nov. gen., nov. sp., M. askomorpha nov. sp., Daharella triassica nov. sp., Acoelia norica nov. sp., Tyanada irregularis nov. gen, nov. sp., Taurispongia oligocanalis nov. gen., nov. sp., T. polycanalis nov. sp., T. tenuis nov. sp., T. lamellicanalis nov. sp., T. fascifera nov. sp., T. siderifera nov. sp., T. lamellata nov. sp., T. polyforma nov. sp., Wildspongia? krystyni nov. sp., Caelispongia topukensis nov. gen., nov. sp., Tenuipariespongia taurica nov. sp., Obscurospongia chaetetiformis nov. gen., nov. sp. The sponge fauna of the Norian reef boulders of Dereköy Basin (Dereköy localities) differs distinctly from reef boulders of the Kasımlar Basin. Also the high diversity of sponges and other reef organisms in Dereköy Basin and the ecological conditions of the growth style of organisms separates the faunal associations of both basins. The Turkish species are compared with time equivalent inozoan fauna from the Northern Calcareous Alps (NCA) from Sicily and from Iran in species level. Among 33 described species of inozoans from Turkey 6 species are known from the Alps, 8 from Sicily and 7 from Iran. The Norian inozoan fauna of Taurus Mts. shows 19.3% similarity to the Norian fauna of the Alps, 25.8% to the fauna of Sicily and 22.5% to the Iranian. It can be stated, that 18 (54.5%) out of 33 described species of inozoans of the Norian boulders from this region are described as new and are endemic. The most endemic and peculiar species were collected from the Dereköy localities.
UnivIS-Import:2017-11-07:Pub.2016.nat.dgeo.IGM.LP.hyperc
Keywords: Inozoa; Norian; Sponges; Taurus Mountains; Triassic; Turkey

Hypercalcified segmented sponges ("sphinctozoans) from the Upper Triassic (Norian) reef boulders of Taurus Mountains (southern Turkey) - Senowbari-Daryan, Baba; Link, Michael (Facies, 2011)
Upper Triassic Norian reef boulders, exposed in a locality near the fountain "Tavuk Cesme" ("Chicken Fountain") in Taurus Mountains, southern Turkey yielded a large number of hypercalcified sponges, including "sphinctozoans", "inozoans", "spongiomorphids", and "chaetetids". The sphinctozoans from this locality are described in this paper. Geologically, this locality belongs to the Anamas-Akseki autochthonous. The reef boulders of this locality are exposed near the "Tavuk Cesme" fountain, located at the road, leading from the town of Aksu to Yenisarbademli. The following taxa are described: Amblysiphonella taurica nov. sp., Anthalythalamia riedeli Senowbari-Daryan, Calabrisiphonella sphaerica nov. sp., Calabrisiphonella cuifi nov. sp., Cinnabaria minima Senowbari-Daryan, Colospongia recta nov. sp., Colospongia sp. 1, Colospongia sp. 2, Colospongia sp. 3, Cryptocoelia compacta nov. sp., Cryptocoelia? sp., Deningeria crassireticulata Senowbari-Daryan, Zühlke, Bechstädt and Flügel, Discosiphonella minima Senowbari-Daryan and Link, Gigantothalamia ovoidalis Senowbari-Daryan, Hajarispongia dipoyrazensis nov. sp., Hajarispongia cortexifera nov. sp., Kashanella irregularis Senowbari-Daryan, Kashanella cylindrica nov. sp., Parauvanella ferdowsensis Senowbari-Daryan, Parastylothalamia cylindrica nov. gen., nov. sp., Asiphothalamia polyosculata nov. gen, nov. sp., Sollasia norica nov. sp., and Thaumastocoelia sphaeroida Senowbari-Daryan. The most abundant sponge is Amblysiphonella taurica nov. sp. followed by Hajarispongia dipoyrazensis nov. sp., Colospongia and Discosiphonella minima Senowbari-Daryan and Link are also relatively abundant. The stylothalamid sponge Parastylothalamia nov. gen. is an abundant sponge genus in other Norian reefs of the Taurus Mountains, but is rare at the "Tavuk Cesme" locality. © 2011 Her Majesty the Queen in Rights of UK.
UnivIS-Import:2015-04-14:Pub.2011.nat.dgeo.IGM.LP.hyperc_5
Keywords: Norian; Reef; Sphinctozoa; Sponge; Taurus Mountains; Triassic; Turkey

Ice volume and paleoclimate history of the Late Paleozoic Ice Age from conodont apatite oxygen isotopes from Naqing (Guizhou, China) - Chen, Bo; Joachimski, Michael; Wang, Xiangdong; Shen, Shuzhong; Qi, Yueping; Qie, W. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2016)
A high-resolution and continuous conodont apatite oxygen isotope record spanning the late Viséan to Middle Permian is reported from South China, which is interpreted with respect to the ice volume and/or tropical seawater temperature history of the Late Paleozoic Ice Age (LPIA). The presented δO record shows significant fluctuations in δO from the late Viséan to Middle Permian with highest values observed in the Bashkirian (Early Pennsylvanian). The δO maximum coincides with a major eustatic sea level fall recorded in low-latitude successions and postdates the significant increases in Sr/Sr and δC measured on well-preserved brachiopod calcite, which can be interpreted as reflecting intensified weathering as consequence of the closure of Rheic Ocean as well as enhanced carbon burial. Both processes may have contributed to lower greenhouse gas levels and cooled down the Earth's surface, triggering the maximum glaciation. The high Bashkirian δO values are interpreted to represent the glacial maximum of the LPIA. A coeval change in faunal composition and a decreasing diversity in climate-sensitive marine invertebrates can be ascribed to icehouse cooling and/or loss of habitat. Despite inconsistencies with earlier interpretations that the Early Permian represented the glacial maximum of the LPIA as inferred from Gondwanan glacial sediments records, the suggested Bashkirian glacial maximum agrees well with ice extent estimates based on the regional tectonic history in Gondwana, which suggests that the Bashkirian glaciation occurred during Gondwana interior uplift promoting maximum ice cover of the entire LPIA. However, maximum glaciation is only poorly represented in the depositional record because large parts of the glacial deposits were possibly removed by erosion as outlined by a major regional unconformity.
Keywords: Bashkirian; Conodont apatite; Late Palaeozoic Ice Age; Maximum glaciation; Naqing section; Oxygen isotopes

Identification of constitutive and geometrical parameters for slope instability modelling - Application to mountain-splitting area Reutte/Tyrol (Austria) - Meier, Jörg; Datcheva, Maria D.; Moser, Michael; Schanz, Tom (Austrian Journal of Earth Sciences, 2009)
Keywords: Numerical Modelling; Back-analysis; Slope Instability; Particle Swarm Optimization

Identifying crystal accumulation and melt extraction during formation of high-silica granite - Lu, Tianyu; He, Zhen-Yu; Klemd, Reiner (Geology, 2022)
High-silica (>70 wt% SiO2) magmas are usually believed to form via shallow crustal-level fractional crystallization of intermediate magmas. However, the broad applicability of this model is controversial, because the required crystal-melt separation processes have rarely been documented globally up to now. The ca. 50 Ma Nyemo composite pluton of the Gangdese batholith belt in southern Tibet, which comprises intrusive rocks with intermediate-to high-silica compositions (65-78 wt%), offers a unique opportunity for substantiating the coexistence of extracted melts and complementary silicic cumulates in one of Earth's most complete transcrustal silicic magmatic systems. The Nyemo pluton intrusive rocks exhibit similar zircon Hf isotopic compositional ranges (mean epsilon(Hf(t)) = +5.7 to +8.3), suggesting a common, non-radiogenic magma source with crustal assimilation in the deep crust. Yet, these rocks have distinct geochemical characteristics. High-silica miarolitic and rapakivi granites are strongly depleted in Ba, Sr, and Eu, and their zircon trace elements show extremely low Eu/Eu* and Dy/Yb. In contrast, monzogranite is relatively enriched in Ba and Sr with minor Eu anomalies, and the zircon trace elements are characterized by relatively high Eu/Eu* and Dy/Yb. Therefore, we propose that the high-silica granites represent highly fractionated melt extracted from a mush reservoir at unusually low storage pressure (similar to 99-119 MPa), and that the monzogranite constitutes the complementary residual silicic cumulates.
CRIS-Team WoS Importer:2022-02-11

Ignoring Fossil Age Uncertainty Leads to Inaccurate Topology and Divergence Time Estimates in Time Calibrated Tree Inference - Barido-Sottani, Joelle; Van Tiel, Nina M. A.; Hopkins, Melanie J.; Wright, David F.; Stadler, Tanja; Warnock, Rachel (Frontiers in Ecology and Evolution, 2020)
Time calibrated trees are challenging to estimate for many extinct groups of species due to the incompleteness of the rock and fossil records. Additionally, the precise age of a sample is typically not known as it may have occurred at any time during the time interval spanned by the rock layer. Bayesian phylogenetic approaches provide a coherent framework for incorporating multiple sources of evidence and uncertainty. In this study, we simulate datasets with characteristics typical of Palaeozoic marine invertebrates, in terms of character and taxon sampling. We use these datasets to examine the impact of different age handling methods on estimated topologies and divergence times obtained using the fossilized birth-death process. Our results reiterate the importance of modeling fossil age uncertainty, although we find that the relative impact of fossil age uncertainty depends on both fossil taxon sampling and character sampling. Sampling the fossil ages as part of the inference gives topology and divergence time estimates that are as good as those obtained by fixing ages to the truth, whereas fixing fossil ages to incorrect values results in higher error and lower coverage. The relative effect increases with increased fossil and character sampling. Modeling fossil age uncertainty is thus critical, as fixing incorrect fossil ages will negate the benefits of improved fossil and character sampling.
CRIS-Team WoS Importer:2020-08-07

ImageJ and 3D Slicer : open source 2 / 3D morphometric software - Pye, Fiona; Raja Schoob, Nussaibah Begum; Shirley, Bryan; Kocsis, Ádám; Hohmann, Niklas; Murdock, Ducan JE; Jarochowska, Emilia (Open Data and Analysis: from morphology to evolutionary patterns, 2019)
In a world where an increasing number of resources are hidden behind paywalls and monthly subscriptions, it is becoming crucial for the scientific community to invest energy into freely available, community-maintained systems. Open-source software projects offer a solution, with freely available code which users can utilise and modify, under an open source licence. In addition to software accessibility and methodological repeatability, this also enables and encourages the development of new tools. As palaeontology moves towards data driven methodologies, it is becoming more important to acquire and provide high quality data through reproducible systematic procedures. Within the field of morphometrics, it is vital to adopt digital methods that help mitigate human bias from data collection. In addition,m mathematically founded approaches can reduce subjective decisions which plague classical data. This can be further developed through automation, which increases the efficiency of data collection and analysis. With these concepts in mind, we introduce two open-source shape analysis software, that arose from projects within the medical imaging field. These are ImageJ, an image processing program with batch processing features, and 3DSlicer which focuses on 3D informatics and visualisation. They are easily extensible using common programming languages, with 3DSlicer containing an internal python interactor, and ImageJ allowing the incorporation of several programming languages within its interface alongside its own simplified macro language. Additional features created by other users are readily available, on GitHub or through the software itself. In the examples presented, an ImageJ plugin “FossilJ” has been developed which provides semi-automated morphometric bivalve data collection. 3DSlicer is used with the extension SPHARM-PDM, applied to synchrotron scans of coniform conodonts for comparative morphometrics, for which small assistant tools have been created.

Immobilisierung von halogenidhaltigen Rückständen durch Bildung lamellarer Calciumferrathydrate - Götz-Neunhoeffer, Friedlinde; Pöllmann, Herbert (Schweizerbart und Borntraeger, 1994)
UnivIS-Import:2015-03-05:Pub.1994.nat.dgeo.IGM.LM.immobi_4

Immobilisierung von Schadstoffen durch Anwendung des Konzeptes der "Inneren Barriere" auf hochbelastete Rückstände - Neubauer, Jürgen; Pöllmann, Herbert (European Journal of Mineralogy, 1994)
UnivIS-Import:2015-03-05:Pub.1994.nat.dgeo.IGM.LM.immobi

Immobilisierung von Schadstoffen durch gezielte Speichermineralbildung - Pöllmann, Herbert; Neubauer, Jürgen; Vetter, Gerhard (Wasser und Boden, 1996)
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LM.immobi

Impact of arid surface mega-cracks on hydrocarbon reservoir properties - Antrett, Philipp; Vackiner, Anna Alexandra; Kukla, Peter; Klitzsch, Norbert; Stollhofen, Harald (Aapg Bulletin, 2012)
The megacrack pattern of the ephemeral north Panamint dry lake, California,United States, is characterized by variably sized polygons with diameters ranging from hundreds of meters to meters. The evolution and subsurface extent of this polygonal pattern and a probable tectonic link are examined by ground resistivity measurements and surface mapping. Crack development is initiated by the shrinking of clays caused by changes in water content near the surface. For crack evolution, the following processes are proposed: Cavities develop at approximately 1-m (∼3-ft) depth during a subsurface phase, followed by the collapse of the overburden into the existing cavities to form the surface cracks. Cracks are filled by wind-blown sand and dried-out lake sediments from collapsing crack walls. Following burial, differences in competence between crack-fill and surrounding playa-lake sediments provide zones of structural weakness that might channelize stress release and faulting. Ground resistivity measurements confirmed the extent of the cracks to a depth of more than 3 m (>9 ft). The megacrack pattern is compared to a Rotliegende (Upper Permian) tight gas field, located in the southern Permian Basin of northwestern Germany, situated in a comparable geologic setting. There, a multidirectional polygonal pattern is recorded on horizon slices of three-dimensional seismic data and compares well to our observations from the Panamint Valley. The Rotliegende pattern is associated with low-offset faults, which are proposed to be responsible for subtle reservoir compartmentalization.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.impact

Impact of environmental barriers on temnospondyl biogeography and dispersal during the Middle–Late Triassic - Moreno, Raphael; Dunne, Emma; Mujal, Eudald; Farnsworth, Alexander; Valdes, Paul J.; Schoch, Rainer R. (Palaeontology, 2024)
Temnospondyls had a remarkable worldwide distribution throughout the Triassic at a time of periodic arid climates, and were a stable component of Triassic terrestrial ecosystems. Given the postulated ancestral relationship between temnospondyls and modern lissamphibians it is pertinent to recognize that the group may have exhibited some degree of ecological resilience and adaptability. Despite this higher level of plasticity, temnospondyls might still have been susceptible to environmental and climate changes. Although fossil sites are distributed sporadically, we try to circumvent the present geographical and geological biases by combining actual fossil occurrences with environmental conditions derived from general circulation models. Here, we employ species distribution modelling to examine the palaeogeographic and palaeoclimatic distribution of European temnospondyls during the transition from Middle to Late Triassic. The model shows different suitable areas for temnospondyl habitats that give new potential insights on the biogeographic distribution patterns and dispersal potential. We suggest that the Central European Basin functioned as a focal point for Triassic temnospondyl diversification and spread. Moreover, this paper provides the first application of species distribution modelling for Triassic temnospondyls and aids in understanding their climatic niche occupation and evolution.
CRIS-Team Scopus Importer:2024-09-13
Keywords: biogeography; palaeobiology; palaeoclimate; species distribution model; Temnospondyli; Triassic

Impact of initial CA dissolution on the hydration mechanism of CAC - Hüller, Florian; Naber, Christoph; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2018)
Usually, for basic investigations on the hydration behaviour of CA (monocalcium aluminate, CaAl2O4) preferably pure samples without the presence of other hydraulic phases are used. In the presented study we apply an alternative approach investigating mixes that contain tiny to low amounts of CA (0.5–20 wt%) besides CA2 (CaAl4O7) or C6AF2 (Ca6Al2Fe4O15). The hydration of the mixes is investigated by isothermal heat flow calorimetry, in-situ XRD and pore solution analysis at 23 °C. A modified thermodynamic database enables the calculation of saturation indices for relevant hydrate phases in the investigated systems. CA similarly influences the hydration of both CA2 and C6AF2 although the exact impact strongly depends on the initial CA/water ratio in the mixes. Up to a certain amount CA is completely consumed during the first minutes after mixing. Beyond this amount the presence of undissolved CA causes an induction period and retards the hydration of CA2 or C6AF2.<br
Keywords: Thermodynamic calculations (B); Hydration (A); Calcium aluminate cement (D); Pore solution (B); Kinetics (A)

Impact of KOH on the interfacial precipitation rates of C-S-H during the early hydration of C3S - Wagner, Daniel; Bellmann, Frank; Neubauer, Jürgen (Cement and Concrete Research, 2021)
In this work we investigated the influence of alkalis on the hydration of two triclinic samples of C3S. One pure C3S and one Al-doped C3S (0.5 wt.-% Al2O3). We added differently concentrated KOH solutions representing alkalis in the pore solution, which lead to an increase of the interfacial precipitation rates of C-S-H during the hydration of C3S compared to the hydration without KOH. Isothermal calorimetry was conducted for the determination of the rates of reaction during the hydration process and ICP-OES measurements for the determination of the pore solution composition at certain times of hydration. The increasing effect of KOH solution on the calculated interfacial precipitation rates from pore solution data can explain the enhancement of the rates of reaction recorded by heat flow calorimetry during the early hydration. Therefore, the interfacial precipitation rates of C-S-H can accurately describe the acceleration effect of alkalis on the early hydration of C3S.<br
CRIS-Team Scopus Importer:2021-06-11
Keywords: Alkalis (D); Ca; Calcium-Aluminium-Silicate-Hydrate (B); Calcium-Silicate-Hydrate (B); Hydration (A)

Impact of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis) - Gazeau, Frédéric; Alliouane, Samir; Bock, Christian; Bramanti, Lorenzo; López Correa, Matthias; Gentile, Miriam; Hirse, Timo; Pörtner, Hans-Otto; Ziveri, Patrizia (frontiers in Marine Science, 2014)
In order to assess the effects of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis), specimens were reared in aquarium tanks and exposed to elevated conditions of temperature (+3°C) and acidity (−0.3 pH units) for a period of 10 months. The whole system comprised a factorial experimental design with 4 treatments (3 aquaria per treatment): control, lowered pH, elevated temperature, and lowered pH/elevated temperature. Mortality was estimated on a weekly basis and every 2 months, various biometrical parameters and physiological processes were measured: somatic and shell growth, metabolic rates and body fluid acid-base parameters. Mussels were highly sensitive to warming, with 100% mortality observed under elevated temperature at the end of our experiment in October. Mortality rates increased drastically in summer, when water temperature exceeded 25°C. In contrast, our results suggest that survival of this species will not be affected by a pH decrease of 0.3 in the Mediterranean Sea. Somatic and shell growth did not appear very sensitive to ocean acidification and warming during most of the experiment, but were reduced, after summer, in the lowered pH treatment. This was consistent with measured shell net dissolution and observed loss of periostracum, as well as uncompensated extracellular acidosis in the lowered pH treatment indicating a progressive insufficiency in acid-base regulation capacity. However, based on the present dataset, we cannot elucidate if these decreases in growth and regulation capacities after summer are a consequence of lower pH levels during that period or a consequence of a combined effect of acidification and warming. To summarize, while ocean acidification will potentially contribute to lower growth rates, especially in summer when mussels are exposed to sub-optimal conditions, ocean warming will likely pose more serious threats to Mediterranean mussels in this region in the coming decades.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LP.impact
Keywords: ocean acidification

Impact of varying Li2CO3 additions on the hydration of ternary CSA-OPC-anhydrite mixes - Wolf, Julian; Jansen, Daniel; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2020)
The effects of varying Li2CO3 additions on the hydration kinetics of a ternary CSA-OPC-anhydrite system were investigated. The presence of Li led to increased ye'elimite and C3S dissolution as well as accelerated ettringite precipitation. Excessive additions however resulted in heavily decreased ye'elimite dissolution and hydration kinetics after the initial period as evidenced by heat-flow-calorimetry and in-situ XRD. Pore solution analysis showed that the decreased ye'elimite dissolution can be linked to remarkably high Ca/Al-ratios which correspond to the induction period in CSA based systems combined with retarding agents. The early precipitated silicon incorporating hydrate phase in these systems is either straetlingite or a zeolitic phase. The high Li-addition led to a dissolution of these phases in favor of C-S-H precipitation. Consequently, the formed hydrate phase assemblage was changed from ettringite, AH3 and straetlingite or Ca-zeolite in the reference and low Li2CO3 system to ettringite and C-S-H precipitation in the highly dosed Li system.
CRIS-Team Scopus Importer:2020-03-06
Keywords: Acceleration (A); Hydration (A); Lithium compounds (D); Portland cement (D); Sulfoaluminate (D)

Impacts of global climate change on the floras of oceanic islands - Projections, implications and current knowledge - Harter, David; Irl, Severin; Seo, Bumsuk; Steinbauer, Manuel; Gillespie, Rosemary; Triantis, Kostas; Fernández-Palacios, José Maria; Beierkuhnlein, Carl (Perspectives in Plant Ecology Evolution and Systematics, 2015)
Recent climate projections indicate substantial environmental alterations in oceanic island regions during the 21st century, setting up profound threats to insular floras. Inherent characteristics of island species and ecosystems (e.g. small population sizes, low habitat availability, isolated evolution, low functional redundancy) cause a particular vulnerability. Strong local anthropogenic pressures interact with climate change impacts and increase threats. Owing to the high degree of endemism in their floras, a disproportionally high potential for global biodiversity loss originates from climate change impacts on oceanic islands. We reviewed a growing body of research, finding evidence of emerging climate change influences as well as high potentials of future impacts on insular species and ecosystems. Threats from global climate change are not evenly distributed among the world's oceanic islands but rather vary with intrinsic (e.g. island area, structure, age and ecological complexity) and extrinsic factors (regional character, magnitude and rate of climatic alterations, local human influences). The greatest flora vulnerabilities to climate change impacts can be expected on islands of small area, low elevation and homogeneous topography. Islands of low functional redundancies will particularly suffer from high rates of co-modifications and co-extinctions due to climate-change-driven disruptions of ecological interactions. High threat potentials come from synergistic interactions between different factors, especially between climatic changes and local anthropogenic encroachments on native species and ecosystems. In addition, human responses to climate change can cause strong indirect impacts on island floras, making highly populated islands very vulnerable to secondary (derivative) effects. We provide an integrated overview of climate change-driven processes affecting oceanic island plants and depict knowledge gaps and uncertainties. The suitability of oceanic islands and their ecosystems for potential research on the field of climate change ecology is highlighted and implications for adequate research approaches are given.
Keywords: Global warming; Island biogeography; Island endemics; Oceanic buffering; Sea-level rise; Susceptibility

Implications for C3S kinetics from combined C3S/CA hydration - Nehring, Jörg; Naber, Christoph; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Journal of the American Ceramic Society, 2018)
Keywords: Cements; Hydration; Calcium aluminate; Calcium silicate; X-ray methods

Improving the relevance of paleontology to climate change policy - Kießling, Wolfgang; Smith, Jansen; Raja, Nussaïbah Begum (Proceedings of the National Academy of Sciences of the United States of America, 2023)
Paleontology has provided invaluable basic knowledge on the history of life on Earth. The discipline can also provide substantial knowledge to societal challenges such as climate change. The long-term perspective of climate change impacts on natural systems is both a unique selling point and a major obstacle to becoming more pertinent for policy-relevant bodies like the Intergovernmental Panel on Climate Change (IPCC). Repeated experiments on the impacts of climate change without anthropogenic disturbance facilitate the extraction of climate triggers in biodiversity changes. At the same time, the long timescales over which paleontological changes are usually assessed are beyond the scope of policymakers. Based on first-hand experience with the IPCC and a quantitative analysis of its cited literature, we argue that the differences in temporal scope are less of an issue than inappropriate framing and reporting of most paleontological publications. Accepting that some obstacles will remain, paleontology can quickly improve its relevance by targeting climate change impacts more directly and focusing on effect sizes and relevance for projections, particularly on higher-end climate change scenarios.
CRIS-Team Scopus Importer:2023-02-17
Keywords: biodiversity; climate change; IPCC; paleobiology

Improving Thermal Efficiency of horizontal ground heat exchangers - Di Sipio, Eloisa; Bertermann, David; Psyk, Mario; Popp, Thomas (EGC 2016- European Geothermal Congress Proceedings, 2016)
Keywords: environment resources and sustainability; very shallow geothermal systems; thermal conductivity; backfilling material; heat baskets

Incised valley fill sandstone bodies in Upper Carboniferous fluvio-deltaic strata: recognition and reservoir characterization of Southern North Sea analogues. - Hampson, Gary; Elliott, Trevor; Flint, Steve; Stollhofen, Harald (Petroleum Geology of Northwest Europe: Proceed. 5th Conf., 1999)
Multistorey fluvial sandstone bodies in Upper Carboniferous fluvio-deltaic strata are proven reservoirs in the Southern North Sea. Several of these bodies have been interpreted as incised valley fills. Analogous valley fill sandstone bodies have been studied in outcrop and subsurface datasets from Upper Carboniferous successions in the onshore UK and Germany. Using techniques and tools applicable to Southern North Sea datasets, we review the diagnostic criteria of these valley fills: (1) stratigraphic context, characterized by deep erosion into underlying strata, lateral correlation to an interfluve surface and intimate association with an initial flooding surface in overlying strata; (2) basinward facies shift at the base of the sandstone body; (3) erosion of underlying time markers; and (4) distinctive internal architecture, which reflects increasing accommodation space during valley filling. Several features of onshore valley fill sandstones have been characterized in order to constrain the properties of analogous valley fill reservoirs in the Southern North Sea. (1) Valley geometry and extent. Studied onshore valley fills generally have a uniform thickness of 20-25 m, thickening locally to 30-45 m, and widths of 5-25 km. A small number of valley fills, associated with turbidite-fronted deltas, thicken to 50-80m in the 2-5 km adjacent to their mouths. Sheet-like fluvial sandstones overlying sequence boundaries have thicknesses comparable to conventional valley fills, but exceed 35-70 km in width. (2) Valley connectivity; typically, valley fills occur as discrete sandstone bodies, but they may amalgamate laterally, to form sheet-like sandstones, and vertically, producing thick (up to 200 m) sand-prone stratigraphic packages. The internal geometry of these sand-prone packages is complex. (3) Valley fill character. Valley fills generally lack an overall fining-upwards trend and are dominated by coarse- to medium-grained sandstone of low-sinuosity (braided?) fluvial facies throughout. Where present, fine-grained facies are preferentially preserved in the upper part of a valley fill. (4) Detrital mineralogy and provenance. At least some valley fill sandstones exhibit a different composition and provenance to surrounding strata. Such valley fill sandstones are likely to be anomalously feldspathic in the Southern North Sea. © Petroleum Geology '86 Ltd. Published by the Geological Society, London.
UnivIS-Import:2015-04-20:Pub.1999.nat.dgeo.IGM.LG.incise

INCORPORATING INFORMATION ON VARYING SEDIMENTATION RATES INTO PALEONTOLOGICAL ANALYSES - Hohmann, Niklas (Palaios, 2021)
Stratigraphic changes in the clustering of first or last taxon occurrences are a joint expression of evolutionary, ecological, taphonomic, and sedimentological processes. Sedimentation rates control the degree of sedimentary dilution and condensation and thus alter the time contained in a given thickness of sediment. However, it remains poorly explored quantitatively how distinct the stratigraphic patterns in the first and last occurrences can be under different deposition models with a constant thickness of accumulated sediment. Here, I present an algorithm that translates ecological or evolutionary signals between time and stratigraphic height. It is implemented for R Software as the package DAIME and complemented by tools to quantify the uncertainties associated with the construction of deposition models. By modeling the stratigraphic expression of the K/Pg extinction and an earlier extinction pulse potentially linked to Deccan volcanism on Seymour Island under varying sedimentation rates, I show that (1) clustering of last occurrences similar to 250 kyr prior to the K/Pg boundary can be equally explained by a stronger earlier extinction pulse or prolonged intervals with reduced sediment accumulation rate, but (2) when the temporal variability in sedimentation rate is known, the most plausible extinction dynamics can still be identified. The approach is applicable for any type of information transported as a part of the sedimentary record (e.g., fossils or trace elements) or data derived from it (e.g., isotope ratios and rates of morphological evolution).
CRIS-Team WoS Importer:2021-05-14

Increased extinction in the emergence of novel ecological communities - Pandolfi, John M.; Staples, Timothy L.; Kießling, Wolfgang (Science, 2020)
Environmental change is transforming ecological assemblages into new configurations, resulting in novel communities. We developed a robust methodology to detect novel communities, examine patterns of emergence, and quantify probabilities of local demographic turnover in transitions to and from novel communities. Using a global dataset of Cenozoic marine plankton communities, we found that the probability of local extinction, origination, and emigration during transitions to a novel community increased two to four times that of background community changes. Although rare, novel communities were five times more likely than chance to shift into another novel state. For marine plankton communities at a 100,000-year time grain, novel communities were sensitive to further extinctions and substantial community change.
CRIS-Team Scopus Importer:2020-10-23

Increased monocarbonate formation during long-term hydration of CAC-limestone binder by calcium sulfate addition – A temperature-dependent XRD study - Rost, Pauline; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2024)
The long-term hydration of a mix with and without gypsum addition was investigated at 10, 23 and 40 °C by QXRD analysis. In addition, thermodynamic modelling was performed on all systems using GEMS to determine the stable phase composition and the influence of water loss during hydration. The results show that the formation of conversion-sensitive phases such as CAH10 is accelerated at 10 °C and hindered at 23 and 40 °C by the addition of gypsum. Moreover, at all different temperatures, monocarbonate forms next to AH3 as the main hydrate phase and the final phase composition is reached after at least 14 d (at 23 °C and 40 °C already after 2 d). Formation of low amounts ettringite only occurs at 10 and 23 °C during the entire storage time. At 40 °C, however, ettringite is not observed, which is probably due to water loss in the mix until 2 d.
Created from Fastlane, Scopus look-up
Keywords: Calcium aluminate cement (D); Ettringite (D); Hydration (A); Monocarbonate (D); Temperature (A); X-ray diffraction (B)

Increase in marine provinciality over the last 250 million years governed more by climate change than plate tectonics - Kocsis, Ádám; Reddin, Carl James; Scotese, Christopher R.; Valdes, Paul J.; Kießling, Wolfgang (Proceedings of the Royal Society of London, Series B: Biological Sciences, 2021)
Amidst long-term fluctuations of the abiotic environment, the degree to which life organizes into distinct biogeographic provinces (provinciality) can reveal the fundamental drivers of global biodiversity. Our understanding of present-day biogeography implies that changes in the distribution of continents across climatic zones have predictable effects on habitat distribution, dispersal barriers and the evolution of provinciality. To assess marine provinciality through the Phanerozoic, here we (a) simulate provinces based on palaeogeographic reconstructions and global climate models and (b) contrast them with empirically derived provinces that we define using network analysis of fossil occurrences. Simulated and empirical patterns match reasonably well and consistently suggest a greater than 15% increase in provinciality since the Mesozoic era. Although both factors played a role, the simulations imply that the effect of the latitudinal temperature gradient has been twice as important in determining marine provinciality as continental configuration.
CRIS-Team WoS Importer:2021-09-03

Increase of island endemism with altitude - speciation processes on oceanic islands - Steinbauer, Manuel; Otto, Rüdiger; Naranjo-Cigala, Augustin; Beierkuhnlein, Carl; Fernández-Palacios, José Maria (Ecography, 2012)
Understanding speciation on oceanic islands is a major topic in current research on island biogeography. Within this context, it is not an easy task to differentiate between the influence of elevation as an indicator for habitat diversity and island age as an indicator for the time available for diversification. One reason for this is that erosion processes reduce the elevation of islands over time. In addition, the geographic distance to source ecosystems might differ among habitats, which could lead to habitat-specific reduction of species immigration, niche occupation and diversification. We used the percentage of single island endemic species (pSIE) in five different zonal ecosystems (distributed in altitude) on the Canary Islands as an indicator for diversification. We tested whether diversification increases with altitude due to a greater ecological isolation of high elevation ecosystems on oceanic islands under the assumption of a low elevation source region on the mainland. In addition we tested whether the ‘hump-shaped’ (unimodal) relationship between pSIE and island age as well as the linear relationship between species richness and pSIE is consistent across spatial scales. We also analyse a potential influence of island area and habitat area. We found that pSIE increases with elevation. The relations between species richness as well as age with pSIE are consistent across scales. We conclude that high elevation ecosystems are ecologically isolated. Surprisingly, the altitudinal belt with the strongest human influences has the highest values of pSIE. We successfully transfer the ‘general dynamic theory of island biogeography’ to the ecosystem scale, which provides multiple opportunities for future studies. With this approach we find that the effects of elevation on diversification can be separated from those of island age.

Increasing control over biomineralization in conodont evolution - Shirley, Bryan; Leonhard, Isabella; Murdock, Duncan J.E.; Repetski, John; Świś, Przemysław; Bestmann, Michel; Trimby, Pat; Ohl, Markus; Plümper, Oliver; King, Helen E.; Jarochowska, Emilia (Nature Communications, 2024)
Vertebrates use the phosphate mineral apatite in their skeletons, which allowed them to develop tissues such as enamel, characterized by an outstanding combination of hardness and elasticity. It has been hypothesized that the evolution of the earliest vertebrate skeletal tissues, found in the teeth of the extinct group of conodonts, was driven by adaptation to dental function. We test this hypothesis quantitatively and demonstrate that the crystallographic order increased throughout the early evolution of conodont teeth in parallel with morphological adaptation to food processing. With the c-axes of apatite crystals oriented perpendicular to the functional feeding surfaces, the strongest resistance to uniaxial compressional stress is conferred along the long axes of denticles. Our results support increasing control over biomineralization in the first skeletonized vertebrates and allow us to test models of functional morphology and material properties across conodont dental diversity.
CRIS-Team Scopus Importer:2024-06-28

Increasing the equitability of data citation in paleontology: capacity building for the big data future - Smith, Jansen A.; Raja, Nussaïbah Begum; Clements, Thomas; Dimitrijevic, Danijela; Dowding, Elizabeth; Dunne, Emma; Gee, Bryan M.; Godoy, Pedro L.; Lombardi, Elizabeth M.; Mulvey, Laura; Nätscher, Paulina; Reddin, Carl J.; et al. (Paleobiology, 2023)
Data compilations expand the scope of research; however, data citation practice lags behind advances in data use. It remains uncommon for data users to credit data producers in professionally meaningful ways. In paleontology, databases like the Paleobiology Database (PBDB) enable assessment of patterns and processes spanning millions of years, up to global scale. The status quo for data citation creates an imbalance wherein publications drawing data from the PBDB receive significantly more citations (median: 4.3 ± 3.5 citations/year) than the publications producing the data (1.4 ± 1.3 citations/year). By accounting for data reuse where citations were neglected, the projected citation rate for data-provisioning publications approached parity (4.2 ± 2.2 citations/year) and the impact factor of paleontological journals (n = 55) increased by an average of 13.4% (maximum increase = 57.8%) in 2019. Without rebalancing the distribution of scientific credit, emerging “big data” research in paleontology—and science in general—is at risk of undercutting itself through a systematic devaluation of the work that is foundational to the discipline.<br
Keywords: Biodiversity; Open science; Paleobiology Database; Specimen-based; Taxonomy

Indications for pedogenic formation of perylene in a terrestrial soil profile: Depth distribution and first results from stable carbon isotope ratios - Barth, Johannes; et al. (Applied Geochemistry, 2007)

Indicators for the Assessment of the Impact of Hydropeaking on Aquifers - Basilio Hazas, Mónica; Marcolini, G.; Wohlmuth, B.; Chiogna, Gabriele (Geophysical Research Letters, 2024)
The operation of hydropower plants leads to sudden changes in river stage and to a flow regime known as hydropeaking. Hydropeaking alters the morphology of the riverbed and water quality, and ultimately poses a risk to riverine ecosystems. While many indicators are available to quantitatively assess this problem in rivers, the impact of hydropeaking on aquifers is largely unknown and lacks of quantitative indicators. We analyze with wavelet techniques the spatial and temporal dynamics of surface water-groundwater interaction in an aquifer impacted by two differently regulated rivers. We propose four indicators to study the aquifer stress produced by hydropeaking and classify the observed groundwater head time series into weakly, moderately and highly impacted. This study opens the possibility for a quantitative assessment of the impact of hydropeaking on the groundwater ecosystem.
CRIS-Team Scopus Importer:2024-06-28
Keywords: groundwater; hydropeaking; hydropeaking indicators; surface water-groundwater interaction; wavelet analysis

Influence of a dialysed polymer latex on the hydration of OPC – A closer look into adsorption processes - Schreiber, Jakob; Wang, Jian; Kong, Xiangming; Neubauer, Jürgen; Jansen, Daniel (Cement and Concrete Research, 2024)
The impact of a dialysed styrene acrylate copolymer on cement hydration was investigated. The retarding and depressing mechanism of the polymer particles on OPC hydration was examined via heat flow calorimetry, in-situ X-ray analysis and pore solution composition measurements. To ensure excessive polymer particles were remaining in the pore solution during the hydration, a high polymer-cement-ratio was chosen. It is found that the physical mechanism, the adsorption, is the most influential cause of the retardation and depression. Both aluminate and silicate reactions are strongly inhibited by the adsorption of polymer particles on hydrate phases. As long as polymer particles are found in the pore solution, newly forming surfaces are directly occupied by the latex particles, thus delaying the reaction. The OPC hydration is kinetically slowed down by polymer particle adsorption even though thermodynamically there is no hindrance for the hydration progression.
CRIS-Team Scopus Importer:2023-12-15
Keywords: Adsorption (C); Cement (D); Hydration (A); Polymers (D); Retardation (A)

Influence of aluminium on the hydration of triclinic C3S with addition of KOH solution - Wagner, Daniel; Bellmann, Frank; Neubauer, Jürgen (Cement and Concrete Research, 2020)
In this work we studied two samples of triclinic C3S. Namely pure triclinic C3S with no addition of foreign ions and triclinic C3S doped with 0.5 wt.-% Al2O3 to investigate the influence of aluminium on the hydration of C3S in the first 24 h and additionally the effect of KOH solution. During hydration Al-doped C3S shows lower reaction rates in the acceleration period compared to pure C3S. Al ions lead to precipitation of C-A-S-H phase and reduces the overall reactive surface area of C-S-H. Furthermore, Al ions in solution decrease the supersaturation of C-S-H during hydration and therefore the precipitation rates are lower for the Al-doped C3S. The addition of KOH solution leads to a general acceleration of reaction for both C3S samples, but at a concentration of 0.3 mol/L KOH both samples show comparable reaction rates during the main hydration event and the effect of Al is reversed.
CRIS-Team Scopus Importer:2020-08-28
Keywords: Alkalis (D); Ca; Calcium-Aluminium-Silicate-Hydrate (B); Calcium-Silicate-Hydrate (B); Hydration (A)

Influence of carbonates on the riverine carbon cycle in an anthropogenically dominated catchment basin: Evidence from major elements and stable carbon isotopes in the Lagan River (N. Ireland) - Barth, Johannes; et al. (Chemical Geology, 2003)

Influence of crystallinity and surface area on the hydration kinetics of CA2 - Hüller, Florian; Ectors, Dominique; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2016)
The hydration of CA (CaAlO) is usually a slow process. However, we found that CA is easily grindable and that the BET surface area and the amount of X-ray amorphous phase highly influence the hydration kinetics. Tempering of ground samples significantly decreased the BET surface area and the amount of X-ray amorphous phase. The hydration of tempered CA started later and proceeded much more slowly. A different degree of crystallinity of CA explains the wide range of different hydration kinetics and especially the occurrence of the often observed exothermic heat flow peak prior to the CA main reaction. By different grinding procedures and tempering we were able to prepare samples that were completely hydrated within 24 h and such samples which did not react within 24 h. Using heat flow calorimetry, in-situ XRD and in-situ H-TD-NMR we show that X-ray amorphous CA reacts prior to crystalline CA.
Keywords: Amorphous material (B); Calcium aluminate cement (D); Calorimetry (A); Hydration (A); X-ray diffraction (B)

Influence of Deformation and Fluids on Ti Exchange in Natural Quartz - Bestmann, Michel; Pennacchioni, Giorgio; Grasemann, Bernhard; Huet, Benjamin; Jones, Michael W. M.; Kewish, Cameron M. (Journal of Geophysical Research. Solid Earth, 2021)
Using a combination of microstructural, spectroscopic, and geochemical analyses, we investigate how subgrain rotation recrystallization and fluid migration affect Ti concentration [Ti] in naturally deformed quartz veins from the Prijakt Nappe (Austroalpine Unit, Eastern Alps). These coarse-grained quartz veins, that formed at amphibolite facies conditions, were overprinted by lower greenschist facies deformation to different degrees. During the overprint, subgrain rotation recrystallization was dominant during progressive deformation to ultramylonitic stages. The initial [Ti] (3.0-4.7 ppm) and cathodoluminescence (CL) signature of the vein crystals decrease during deformation mainly depending on the availability of fluids across the microstructure. The amount of strain played a subordinate role in resetting to lower [Ti] and corresponding darker CL shades. Using a microstructurally controlled analysis we find that the most complete re-equilibration in recrystallized aggregates ([Ti] of 0.2-0.6 p.m.) occurred (a) in strain shadows around quartz porphyroclasts, acting as fluid sinks, and (b) in localized microshear zones that channelized fluid percolation. [Ti] resetting is mainly observed along wetted high angle boundaries (misorientation angle >10-15 degrees), with partial [Ti] resetting observed along dry low angle boundaries (<10-15 degrees). This study shows for the first time that pure subgrain rotation recrystallization in combination with dissolution-precipitation under retrograde condition provide microstructural domains suitable for the application of titanium-in-quartz geothermobarometry at deformation temperatures down to 300-350 degrees C.
CRIS-Team WoS Importer:2022-02-25

Influence of different CA2/CA-ratios on hydration degree, AH3 content and flexural strength investigated for a binder formulation of calcium aluminate cement with calcite - Goergens, Julian; Belli, Renan; Schulbert, Christian; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2023)
The study was aimed to investigate the influence of the CA2/CA-ratio in an application-orientated binder formulation of calcium aluminate cement (CAC) with calcite. Six mixtures containing varying fractions of two calcium aluminate cements with different CA2- and CA contents, calcite and additives were investigated after 1, 7 and 28 d at 23 °C. By means of QXRD the hydration degrees of CA2 and CA, as well as hydrate phase contents, especially AH3, were determined and correlated with the mechanical response under biaxial flexural stress and pore size distribution using micro-computed tomography (μCT) of three contrastive mixtures. The strength values increase slightly up to a CA2/CA ratio of 70:30, above this ratio the mechanical properties deteriorate significantly. The macro-porosity acting as strength-limiting defects correlate well with this threshold, though not the content of AH3 or the degree of hydration of CA.
CRIS-Team Scopus Importer:2023-01-27
Keywords: Bending strength(C); CaCO; Calcium aluminate cement (D); Hydration (A); X-ray diffraction (B)

Influence of Different Moisture and Load Conditions on Heat Transfer within Soils in Very Shallow Geothermal Application: An Overview of ITER Project - Di Sipio, Eloisa; Bertermann, David (PROCEEDINGS, 42nd Workshop on Geothermal Reservoir Engineering, 2017)
heating/cooling residential and tertiary buildings. Therefore, it is worthy of interest a better comprehension of how the different soil typologies (i.e. sand, loamy sand...) affect and are affected by the heat transfer exchange with heat collectors, especially when horizontal ones (very shallow geothermal installations) are adopted. In this study the preliminary results of ITER Project (http://iter-geo.eu/), funded by European Union, are shown. An overview of physical-thermal properties variations under different moisture and load conditions for different mixtures of natural material is presented, based on laboratory and field test data.
Keywords: very shallow geothermal systems; thermal conductivity; backfilling material; horizontal collector

Influence of granitoid textural parameters on sediment composition: Implications for sediment generation - Caracciolo, Luca; et al. (Sedimentary Geology, 2012)
Keywords: Composition; Glacial environment; Grain size; Mineral interfaces; Sediment generation; Textural parameters

Influence of groundwater levels on effective thermal conductivity of the ground and heat transfer rate of borehole heat exchangers - Luo, Jin; Tuo, Jiasheng; Huang, Wei; Zhu, Yongqiang; Jiao, Yuyong; Xiang, Wei; Rohn, Joachim (Applied Thermal Engineering, 2018)
Effective thermal conductivity of the ground and heat transfer rate of Borehole Heat Exchanger (BHE) are two key parameters for an optimum design and planning of Ground Source Heat Pump (GSHP) systems. In general, these parameters are determined via Thermal Response Tests (TRT) in the field. Many previous studies reported that groundwater flow has positive effects on TRT to estimate ground thermal conductivity and heat transfer efficiency of BHEs. However, there still lack of data to clarify effect of groundwater levels changes on TRT. In this paper, six TRTs are conducted at two sites with different groundwater levels in a loess deposit area in 2016 and 2017. Effective thermal conductivity and borehole heat transfer rate are determined for BHEs within depth of 120 m. Results show that thermal conductivity increases remarkably with increasing groundwater level. The effective thermal conductivity of the ground is estimated to be 1.64 W/m K and 2.07 W/m K for the groundwater level of 35 m and 10 m depths. Furthermore, heat transfer rate of BHEs increases when increasing groundwater level. The findings obtained from this study indicate that groundwater level changes influence on both effective thermal conductivity of the ground and heat transfer of BHEs. These effects should be taken into account in BHE's design and installations in order to sizing the total length in the areas with seasonal groundwater level changes. © 2017 Elsevier Ltd
Keywords: Geothermal heat pumps; Groundwater; Groundwater flow; Heat exchangers; Heat pump systems; Heat transfer; Borehole heat exchangers; Effective thermal conductivity; Ground thermal conductivity; Heat transfer efficiency; Heat transfer rate; Optimum designs; Thermal response test; Total length; Thermal conductivity

Influence of Groundwater on the Very Shallow Geothermal Potential (vSGP) in the Area of a Large-Scale Geothermal Collector System (LSC) - Rammler, Mario; Zeh, Robin; Bertermann, David (Geosciences, 2023)
The water balance in the very shallow subsurface can be influenced by capillary rise due to a high groundwater table. Since moisture content is an important factor for the thermal conductivity of soils, this can also have an influence on the very shallow geothermal potential (vSGP). For this reason, the effect of spatial and seasonal variations in groundwater tables on moisture content in essential depth layers was investigated at a large-scale geothermal collector system (LSC) in Bad Nauheim, Germany. Quasi-one-dimensional simulations using the FEFLOW® finite-element simulation system were employed to determine site-dependent and seasonally varying moisture contents, from which thermal conductivities were derived. The model setup was previously validated based on recorded moisture contents. The simulations resulted in groundwater-related maximum seasonal and spatial differences in thermal conductivity of 0.14 W/(m∙K) in the LSC area. Larger differences of up to 0.21 W/(m∙K) resulted for different soil textures at the same depth due to different thermal properties. The results indicate that an efficient design of LSCs requires a sufficiently detailed subsurface exploration to account for small-scale variations in grain size distribution and groundwater level.
CRIS-Team Scopus Importer:2023-09-08
Keywords: groundwater; large-scale geothermal collector system (LSC); quasi-one-dimensional simulation; thermal conductivity of soils; very shallow geothermal potential (vSGP)

Influence of magnesium doping on the phase transformation temperature of Beta-TCP ceramics examined by Rietveld refinement - Enderle, Ralph; Götz-Neunhoeffer, Friedlinde; Göbbels, Matthias; Müller, Frank; Greil, Peter (Biomaterials, 2005)
The influence of Mg doping in Ca 3(PO 4) 2 on the transformation temperature of β-tricalcium phosphate (β-TCP) to α-tricalcium phosphate (α-TCP) was examined. A maximum substitution by 14 mol% of Mg 2+ on Ca 2+ sites in the β-TCP structure was determined for powders calcinated at 1025±10°C. X-ray powder diffraction analysis (XRPD) in combination with Rietveld method (TOPAS 2.1) was employed for quantitative phase analysis and structural refinement. The synthesized and characterized Mg-doped samples were sintered in air atmosphere in a vertical tube furnace at suitable temperatures ranging from 1460 to 1680°C and subsequently quenched to room temperature, in order to stabilize α-TCP. The β to α transformation temperatures were determined by differential temperature analysis and XRPD analysis. © 2004 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LM.influe
Keywords: α-TCP; β-TCP; Mg substitution; Rietveld refinement; Transformation temperature; Phase transformation temperature; Rietveld method; Room temperature; Structural refinement

Influence of polyvinyl alcohol on phase development during the hydration of Portland cement - Jansen, Daniel; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hergeth, Wolf Dieter; Härzschel, Reinhard (Zkg International, 2010)
nvestigations into the influence of various polyvinyl alcohols (PVOH) on the hydration of Portland cement have shown that the alumina reaction is affected during the cement hydration. It was found that the dissolving of the sulfate carrier and of the C3A is retarded by the presence of polyvinyl alcohols and also that the ettringite formation is accelerated after about 16 hours hydration.These results were obtained with 3 different polyvinyl alcohols.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LM.influe

Influence of Polyvinyl Alcohol (PVA) on quantitative phase development during early cement hydration - Jansen, Daniel; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hergeth, Wolf Dieter; Härzschel, Reinhard (17. Internationale Baustofftagung - Tagungsbericht, 2009)
Investigations into the influence of various polyvinyl alcohols (PVOH) on the hydration of Portland cement have shown that the alumina reaction is affected during the cement hydration. It was found that the dissolving of the sulfate carrier and of the C 3 A is retarded by the presence of polyvinyl alcohols and also that the ettringite formation is accelerated after about 16 hours hydra - tion. These results were obtained with 3 different polyvinyl alcohols.
UnivIS-Import:2015-04-16:Pub.2009.nat.dgeo.IGM.LM.influe

Influence of shale and mudstone heterogeneity on permeability-driven fluid flow - Sample to geophysical well log scale - Drews, Michael; Kurtev, Kuncho; Ma, Jingsheng; Böker, Ulf; Aplin, Andrew (75th European Association of Geoscientists and Engineers Conference and Exhibition 2013 Incorporating SPE EUROPEC 2013: Changing Frontiers, 2013)

Influence of silica fume addition and content on the early hydration of calcium aluminate cement – The role of soluble silicon - Schramm, Tillmann; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2024)
Hydration of a commercial white calcium aluminate cement (CAC) at 23 °C was modified by silica fume (SF) addition in varying amounts. The process was followed by heat flow calorimetry, quantitative in-situ XRD analysis and Gillmore needle experiments supplemented by pore solution analysis, thermodynamic modelling, and 1H-TD-NMR measurements. Lower SF/cement ratios accelerate the hydration of CAC. Higher ratios trigger an intermediate heat flow event, which is correlated to increased setting rates. This intermediate event (IE) initiates an induction period of constant duration, which appears later with increasing SF/cement ratios. Results show the IE is caused by an initially hindered CA dissolution, in which dissolved silicon provided by SF plays a crucial role. Increasing the [Si] concentration in the pore solution leads to a further retardation of the IE and eventually prevents the entire hydration reaction if a critical amount is reached. A detailed model explaining the observed behavior is proposed.<br
CRIS-Team Scopus Importer:2024-08-02
Keywords: Calcium aluminate cement; Silica fume; Refractory cement; Hydration; Calorimetry; X-ray diffraction; Pore solution; Thermodynamic calculations; Hydration products

Influence of Sr2+ on Calcium-Deficient Hydroxyapatite Formation Kinetics and Morphology in Partially Amorphized α-TCP - Hurle, Katrin; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Journal of the American Ceramic Society, 2015)
Hydration of partially amorphized α-TCP powders with Sr concentrations ranging from 0 to 10 mol% substitution for Ca was analyzed by isothermal calorimetry and quantitative in-situ XRD. Hydration of both crystalline α-TCP and amorphous TCP (ATCP) forming CDHA was retarded to an increasing extent with increasing Sr content. Sr slightly reduced the crystallite size (XRD coherent scattering domains) of the CDHA formed during hydration, while the size of crystals visible under SEM was not noticeably affected. Reaction enthalpies of ΔH = 122 ± 8 J/g and ΔH = 257 ± 8 J/g were determined for the hydration of crystalline α-TCP and ATCP containing 5 mol% Sr substitution for Ca. This is comparable with the corresponding reaction enthalpies previously obtained for undoped samples, which are 106 ± 7 J/g for α-TCP and 250 ± 7 J/g for ATCP.
Keywords: Coherent scattering; Crystalline materials; Crystallite size; Enthalpy; Hydration; Calcium deficient hydroxyapatite; In-situ XRD; Isothermal calorimetry; Reaction enthalpies; XRD

Influence of subducted components on back-arc melting dynamics in the Manus Basin - Beier, Christoph; Turner, Simon P.; Sinton, John M.; Gill, James B. (Geochemistry Geophysics Geosystems, 2010)
Lavas erupted in back-arc basins afford the opportunity to explore the extent to which decompression and subduction-related components influence partial melting in this setting. We present U-Th-Ra disequilibria data from 24 well-characterized lavas from the Manus Basin behind the New Britain volcanic arc, supplemented by some additional trace element and Sr-Nd-Pb isotope data. The lavas range in composition from 49.6 to 57.7 wt % SiO2 and can be subdivided into those that are broadly like mid-ocean ridge basalts (MORB) with Ba/Nb < 16 and back-arc basin basalts (BABB) that are variably influenced by subduction components and have Ba/Nb > 16. Rifts closest to the arc are dominated by BABB, whereas both lavas types erupt further away at the Manus Spreading Center. The MORB have small 230Th excesses (up to 5%) and are displaced below the global correlation of (230Th/238U) with ridge depth. In most respects the BABB closely resemble lavas erupted along the New Britain arc front, including 238U excesses that reach 26%. The Pb isotope data can be explained by mixing of a subduction component into an Indian MORB mantle source. The Pb in the subduction component is derived from both the subducted sediment (5%) and fluids from the subducting altered Solomon Sea oceanic crust (95%), and these were mixed prior to addition to the mantle wedge. U/Th ratios, Fe3+/ΣFe, and H2O contents all increase with increasing 206Pb/204Pb. A model in which addition of the subduction component to the mantle wedge is followed by 230Th in-growth during decompression and dynamic melting all less than 140 kyr prior to eruption can simulate the data. However, our preferred model is one of dynamic decompression melting in which subduction-modified, more oxidized mantle had DU ≪ DTh leading to 238U excesses in contrast to unmodified mantle that yields 230Th excess. Large 226Ra excesses in some southern rift samples require addition of a fluid < 8 kyr ago but elsewhere reflect melting under low-porosity conditions. Copyright 2010 by the American Geophysical Union.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.legeo.influe
Keywords: Back arc; Decompression; Flux melting; Mantle heterogeneity; Melting dynamics; U-Th-Ra disequilibria

Influence of the reactivity of the amorphous part of mechanically activated alite on its hydration kinetics - Bergold, Sebastian; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2016)
The hydration of one mechanically activated alite passing through different drying procedures is examined by heat flow calorimetry and quantitative in-situ XRD analysis. The reactivity of the alite powders is strongly affected by the drying technique. It is shown that the reactivity of the amorphous part of the activated alite sample is particularly affected. Due to the fast initial dissolution of the amorphous “alite” part, the hydration progression is speeded up significantly. However, if the hydration is not speeded up by the amorphous “alite” dissolution, as in the case of surface passivation, the heat released until the transition to the deceleration period will increase. It is discussed that a crystalline alite dissolution by etch pit opening could increase the reactive alite surface and therefore increase the reaction degree at the transition to the deceleration period.
Keywords: Acceleration (A); Ageing (C); Amorphous material (B); Calcium-silicate-hydrate (B); Hydration (A)

Influence of the specific surface area of alumina fillers on CAC hydration kinetics - Klaus, Sebastian; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Advances in Cement Research, 2016)
For refractory application inert alumina fillers frequently are mixed with calcium aluminate cements to improve particle packaging and to reduce the demand of water for low-cement castables. This finally results in decreased porosity and higher strength. Investigations by isothermal heat flow calorimetry show that the presence of alumina filler material with high specific surface area leads to a shortening of the induction period of calcium aluminate cement hydration. The study also demonstrates that the specific surface area of the chosen alumina filler changes the starting point of the main hydration reaction and in consequence the setting time of the calcium aluminate cement mixture is strongly influenced. During the dormant period the heat flow of calcium aluminate cement hydration with coarse alumina filler material of lower specific surface area is characterised by negative values. By addition of filler with higher specific surface area, the surface available for heterogeneous nucleation can be increased. Owing to more available surfaces the critical energy barrier for stable nuclei formation can be reduced. This results in a positive heat flow during the dormant period and a shift of the main reaction to earlier points in time.
Keywords: CRYSTAL STRUCTURE; CEMENT; ADMIXTURES

Influence of titanomagnetite composition on the magnetic anisotropy in a dyke-sill complex in Hungary. - de Wall, Helga; et al. (Abstracts of the Lasi II: Physical geology of subvolcanic systems: Laccoliths, Sills, and Dykes. Portree, Isle of Skye, Scotland. April 1st3rd 2006, 2006)
UnivIS-Import:2015-04-16:Pub.2006.nat.dgeo.IGM.c3tekt.influe

Influence of tree hollow characteristics on saproxylic beetle diversity in a managed forest - Schauer, Bastian; Steinbauer, Manuel; Vailshery, Lionel; Müller, Jörg; Feldhaar, Heike; Obermaier, Elisabeth (Biodiversity and Conservation, 2018)
Tree hollows are key structures in forest ecosystems constituting long-lasting habitats and nutritional resources for many saproxylic arthropod species. Due to diverse microhabitat structures and conditions in tree hollows, they can support a broad range of species. However, in the past intensive management practices in parts of Europe reduced the abundance of tree hollows, resulting in a decrease and endangerment of species specialised in this tree habitat. We investigated 40 beech trees with hollows in 2014 and a subset of 23 of these trees in 2015 in a managed forest landscape in Germany. Using emergence traps we collected 89 beetle species of which 33% were on the Bavarian Red List. We described the tree characteristics, physical hollow characteristics, and their surrounding environment investigating their influence on α-diversity of non-Red List and Red List species. Furthermore, we investigated spatial (between tree hollows) and temporal (same tree hollow but different years) β-diversity, considering the importance of turnover and nestedness components on β-diversity. α-Diversity decreased with increasing decomposition of wood mould and increased with increasing area of hollow entrance in both years. Additional characteristics differed between years and between non-Red List and Red List species. β-Diversity was related to diameter at breast height, number of surrounding tree hollows, area of hollow entrance and a temperature gradient. We found a higher species turnover than nestedness between tree hollows and between years, indicating highly dynamic beetle communities spatially as well as temporally. To support and maintain the diversity of saproxylic beetles inhabiting tree hollows, the heterogeneity of microhabitats is important and should be supported by maintaining the diversity of differently structured and sized tree hollows.

Influence of w/s ratio on alite dissolution and C-S-H precipitation rates during hydration - Naber, Christoph; Bellmann, F.; Neubauer, Jürgen (Cement and Concrete Research, 2020)
The first 24 h of hydration of tricalcium silicate (C3S) have been studied at varying water/solid (w/s) mass ratios ranging from 0.5 to 10. Gathered data comprise the reaction degree, pore solution concentrations and specific surface area evolution. Combined with interfacial C3S dissolution rates and C-S-H precipitation rates found in the literature, these data are used to calculate theoretical reaction rates from C-S-H precipitation and C3S dissolution. Compared with the measured reaction rates, theoretical rates calculated from C-S-H precipitation show a good match, indicating a correct kinetic description of C-S-H precipitation. Theoretical rates calculated from C3S dissolution are higher than expected during the first hours of hydration which could be explained by the buildup of a metastable hydrate phase barrier. Furthermore, a comparison of the reaction rates shows no effect of the w/s ratio. The Ca concentration evolution indicates a delay of the first portlandite precipitation with increasing w/s ratio.
CRIS-Team Scopus Importer:2020-05-02
Keywords: Ca; Calcium-silicate-hydrate (C-S-H) (B); Hydration (A); Kinetics (A); Pore solution (B)

Influences of seawater intrusion and anthropogenic activities on shallow coastal aquifers in Sri Lanka: evidence from hydrogeochemical and stable isotope data - Jayathunga, Kaushalya; Diyabalanage, Saranga; Frank, Alexander; Chandrajith, Rohana; Barth, Johannes (Environmental Science and Pollution Research, 2020)
Water supplies in coastal aquifers throughout the world are often threatened by salinization due to seawater intrusion and anthropogenic activities. In the Kalpitiya Peninsula in Sri Lanka, agricultural and domestic water supplies entirely depend on groundwater resources extracted from unconfined Holocene sandy aquifers. To differentiate the effects of seawater intrusion and agriculture on the coastal aquifers of this 160 km2 peninsula, 43 groundwater samples were collected. These samples were analyzed for major ions, trace elements, and stable isotopes of water (δ18O and δ2H). The solute compositions were dominated by Cl−, SO42−, and HCO3−, which were mostly balanced by Ca2+, Na+, and Mg2+. Among the four main water types, Na+-Cl− and Ca2+-SO42− classifications were predominant in the investigated aquifers. Modifications of the groundwater due to evaporation during irrigation activities, but also due to seawater intrusion seem most plausible as indicated by the correlation of δ18O with δ2H (δ2H = 5.51 * δ18O-3.08, r = 0.93) deviating from the local meteoric water line. Particularly in the southern part of the peninsula, Mg2+/Ca2+ ratios and stable isotopes of water attributed salinization of groundwater to agricultural activities. However, especially in the north, seawater intrusions were also evident. Established mass balance calculations revealed that local groundwater had seawater admixtures of up to 12%. Our results indicate that integrated water management is essential and water resources should critically monitor in the Kalpitiya Peninsula in order to avoid over-exploitation and further seawater inflows.
CRIS-Team Scopus Importer:2020-05-12
Keywords: Agricultural pollution; Coastal aquifers; Irrigation return flows; Kalpitiya peninsula; Seawater intrusion

Insight Into Hartoušov Mofette, Czech Republic: Tales by the Fluids - Daskalopoulou, Kyriaki; Woith, Heiko; Zimmer, Martin; Niedermann, Samuel; Barth, Johannes; Frank, Alexander; Vieth-Hillebrand, Andrea; Vlček, Josef; Bağ, Cemile Dilara; Bauz, Ralf (Frontiers in Earth Science, 2021)
The Cheb Basin (Czech Republic) is characterized by emanations of magma-derived gases and repeated occurrences of mid-crustal earthquake swarms with small to intermediate magnitudes (ML < 4.5). Associated intense mantle degassing occurs at the Hartoušov Mofette, a representative site for the Cheb Basin. Here, we performed 14 sampling campaigns between June 2019 and March 2020. Gas samples of fluids ascending in two boreholes (F1, ∼28 m depth and F2, ∼108 m depth) and from a nearby natural mofette were analyzed for their chemical (CO2, N2, O2, Ar, He, CH4, and H2) and isotope compositions (noble gases and CO2). CO2 concentrations were above 99.1% in most samples, while O2 and N2 were below 0.6%. He ranged from 19 to 34 μmol/mol and CH4 was mostly below 12 μmol/mol. Isotope compositions of helium and carbon in CO2 ranged from 5.39 to 5.86 RA and from −2.4 to −1.3 ‰ versus VPDB, respectively. Solubility differences of the investigated gases resulted in fluctuations of their chemical compositions. These differences were accompanied by observed changes of gas fluxes in the field and at the monitoring station for F1. Variations in solubilities and fluxes also impacted the chemical concentration of the gases and the δ13C values that were also likely influenced by Fischer-Tropsch type reactions. The combination of (a) the Bernard ratio, (b) CH4/3He distributions, (c) P-T conditions, (d) heat flow, and (e) the sedimentary regime led to the hypothesis that CH4 may be of mixed biogenic and volcanic/geothermal origin with a noticeable atmospheric contribution. The drilling of a third borehole (F3) with a depth of ∼238 m in August 2019 has been crucial for providing insights into the complex system of Hartoušov Mofette.
CRIS-Team Scopus Importer:2021-05-07
Keywords: CHcpsdummy4 origin; CO; gas flow perturbations; geogenic degassing; solubility

Insights into agricultural influences and weathering processes from major ion patterns - van Geldern, Robert; Schulte, Peter; Mader, Michael; Baier, Alfons; Barth, Johannes; Juhlke, Tobias; Lee, Kern (Hydrological Processes, 2018)
Karst areas and their catchments pose a great challenge for protection because fast conduit flow results in low natural attenuation of anthropogenic contaminants. Studies of the hydrochemistry of karst sources and river solutes are an important tool for securing and managing water resources. A study of the geochemical downriver evolution of the Wiesent River and its tributaries, located in a typical karst terrain, revealed unexpected downstream decreases of nitrate with maximum mean values of 30mg/L at the source to minimum values of 18mg/L near the river mouth. This trend persisted over the length of the river even though increased agricultural activities are evident in the downstream section of the catchment. This pattern is caused by fertilizer inputs via diffusive and fast conduits flow from karst lithology in the upstream area that may have reached the river's source even from beyond the hydrological catchment boundaries. Further downstream, these influences became diluted by tributary inputs that drain subcatchments dominated by claystone and sandstone lithologies that increased potassium and sulphate concentrations. Our findings indicate that bedrock geology remains the dominant control on the major ion chemistry of the Wiesent River and that agricultural influences are strongest near the headwaters despite increased land use further downstream, due to long-term storage and accumulation in karst aquifers. This feature may not be unique to the Wiesent River system, as carbonates cover significant portions of the Earth's surface and subsequent work in other river systems could establish whether such patterns are ubiquitous worldwide.
Keywords: fertilizers; geochemistry; hydrology; karst; weathering; Wiesent River

Insights into fluid evolution and Re enrichment by mineral micro-analysis and fluid inclusion constraints: Evidence from the Maronia Cu-Mo ± Re ± Au porphyry system in NE Greece - Falkenberg, Jan; Keith, Manuel; Melfos, Vasilios; Hohl, Max; Haase, Karsten; Voudouris, Panagiotis; Höß, Alica; Wenske, Julia; Klemd, Reiner; Beier, Christoph; Kutzschbach, Martin; Strauss, Harald (Mineralium Deposita, 2024)
Porphyry-epithermal veins hosting Re-rich molybdenite and rheniite (ReS2) from the Maronia Cu-Mo ± Re ± Au porphyry in Thrace, NE Greece, provide new insights into the hydrothermal processes causing extreme Re enrichment. Quartz trace element chemistry (Al/Ti, Ge/Ti), Ti-in-quartz thermometry, and cathodoluminescence imaging reveal multiple quartz generations in consecutive hydrothermal quartz-sulfide veins associated with potassic, sericitic, and argillic alteration. Fluid inclusions in different quartz generations indicate that phase separation and fluid cooling are the main ore-forming processes in the porphyry stage ( 500 – 350 °C), whereas mixing of a vapor-rich fluid with metalliferous (e.g., Pb, Zn, Au) meteoric water forms the epithermal veins ( 280 °C). These processes are recorded by trace element ratios in pyrite that are sensitive to changes in fluid temperature (Se/Te), fluid salinity (As/Sb, Co/As), and mixing between fluids of magmatic and meteoric origin (Se/Ge). Highly variable intra-grain δ34S values in pyrite record S isotope fractionation during SO2 disproportionation and phase separation, emphasizing the importance of in situ δ34S analysis to unravel ore-forming processes. High δ34S ( 4.5‰) values of sulfides are indicative of low SO42−/H2S fluid ratios buffered by the local host rocks and mixing of the magma-derived fluid with meteoric water. The formation of Re-rich molybdenite ( 6600 ppm) is favored by cooling and reduction of a magma-derived, high-temperature ( 400 °C), oxidized, and Re-rich fluid triggering efficient Re precipitation in early veins in the potassic alteration zone. The systematic temporal fluid evolution therefore reveals that coeval cooling and reduction of oxidized Re-rich fluids cause extreme Re enrichment at the Maronia porphyry system.
CRIS-Team Scopus Importer:2024-05-10
Keywords: Fluid inclusion microthermometry; In situ S isotopes; LA-ICP-MS; Molybdenite trace elements; Porphyry-epithermal evolution; Pyrite; Quartz; Rheniite; Rhenium

Insights into mantle composition and mantle melting beneath mid-ocean ridges from postspreading volcanism on the fossil Galapagos Rise - Haase, Karsten; Regelous, Marcel; Duncan, Robert; Brandl, Philipp; Stroncik, Nicole; Grevemeyer, Ingo (Geochemistry Geophysics Geosystems, 2011)
New major and trace element and Sr, Nd, and Pb isotope data, together with 39Ar-40Ar ages for lavas from the extinct Galapagos Rise spreading center in the eastern Pacific reveal the evolution in magma compositions erupted during slowdown and after the end of active spreading at a mid-ocean ridge. Lavas erupted at 9.2 Ma, immediately prior to the end of spreading are incompatible element depleted mid-ocean ridge tholeiitic basalts, whereas progressively younger (7.5 to 5.7 Ma) postspreading lavas are increasingly alkalic, have higher concentrations of incompatible elements, higher La/Yb, K/Ti, 87Sr/86Sr, and lower 143Nd/144Nd ratios and were produced by smaller degrees of mantle melting. The large, correlated variations in trace element and isotope compositions can only be explained by melting of heterogenous mantle, in which incompatible trace element enriched lithologies preferentially contribute to smaller degree mantle melts. The effects of variable degrees of melting of heterogeneous mantle on lava compositions must be taken into account when using mid-ocean ridge basalt (MORB) to infer the conditions of melting beneath active spreading ridges. For example, the stronger "garnet signature" inferred from Sm/Nd and 143Nd/144Nd ratios for postspreading lavas from the Galapagos Rise results from a larger contribution from enriched lithologies with high La/Yb and Sm/Yb, rather than from a greater proportion of melting in the stability field of garnet peridotite. Correlations between ridge depth and Sm/Yb and fractionation-corrected Na concentrations in MORB worldwide could result from variations in mantle fertility and/or variations in the average degree of melting, rather than from large variations in mantle temperature. If more fertile mantle lithologies are preferentially melted beneath active spreading ridges, then the upper mantle may be significantly more "depleted" than is generally inferred from the compositions of MORB. Copyright © 2011 by the American Geophysical Union.
Keywords: geochemistry; magmatism; radiogenic isotope

Insights into the Galápagos plume from uranium-series isotopes of recently erupted basalts - Handley, Heather K.; Turner, Simon; Berlo, Kim; Beier, Christoph; Saal, Alberto E. (Geochemistry Geophysics Geosystems, 2011)
Uranium-series isotopes (U-Th- Ra-Pb), major element, trace element, and Sr-Nd isotopic data are presented for recent (<60 years old) Galpagos archipelago basalts. Volcanic rocks from all centers studied (Fernandina, Cerro Azul, Sierra Negra, and Wolf Volcano) display Th excesses (4%-15%) and steep rare earth element (REE) patterns indicative of residual garnet during partial melting of their mantle source. Rare earth element modeling suggests that only a few percent of garnet is involved. Correlations between (U/ Th), radiogenic isotopes and Nb/Zr ratio suggest that the U/Th ratio of these Galpagos volcanic rocks is primarily controlled by geochemical source variations and not fractionation during partial melting. The lowest (Th/U) ratio is not observed at Fernandina (the supposed center of the plume) but at the more geochemically "depleted" Wolf Volcano, further to the north. Small radium excesses are observed for all samples with (Ra/Th) ranging from 1.107 to 1.614. The Ra-Th disequilibria do not correlate with other uranium-series parent-daughter nuclide pairs or geochemical data, suggesting modification at shallow levels on timescales relevant to the half-life of Ra (1600 years). The combination of Ra and Pb excesses is inconsistent with interaction of magma with cumulate material unless decoupling of Pb (or an intermediate daughter, such as Rn) occurs prior to modification of Ra-Th disequilibria. An intriguing correlation of (Pb/ Ra) with Nb/Zr and radiogenic isotopes requires further investigation but suggests possible control via magmatic degassing and accumulation that may somehow be related to source heterogeneities. Copyright 2011 by the American Geophysical Union.
Keywords: ocean island basalts; uranium-series isotopes

In situ 1H-TD-NMR: Quantification and microstructure development during the early hydration of alite and OPC - Ectors, Dominique; Götz-Neunhoeffer, Friedlinde; Hergeth, Wolf Dieter; Dietrich, Ulf; Neubauer, Jürgen (Cement and Concrete Research, 2016)
An in situ framework for H time-domain nuclear magnetic resonance analysis was developed and applied on alite and OPC hydration. Highly time-resolved quantitative data on the evolution of proton reservoirs during hydration was collected for up to 40 h. Reservoirs could be clearly assigned to mobile (mix water), intermediate (C-S-H) and rigid fractions (CH, ettringite). Comparison of determined fraction quantities with data from in situ XRD measurements and heat flow calorimetry show very good agreement. During alite hydration at 23°C, a bulk water content of 4 HO in CSH was confirmed. T2 relaxation times of the mobile fraction shifted towards shorter times from the start of the main reaction until the maximum of the heat flow. Microstructure evolution is nearly finished at that point in time. T2 relaxation times are severely shortened for iron-containing OPC, but are still evaluable.
Keywords: Ca3SiO5; Calcium-silicate-hydrate (C-S-H); Cement; Hydration; Kinetics

In situ 2.0 Ma trees discovered as fossil rooted stumps, lowermost Bed I, Olduvai Gorge, Tanzania - Habermann, Jörg; Stanistreet, Ian G.; Stollhofen, Harald; Albert, Rosa M.; Bamford, Marion K.; Pante, Michael C.; Njau, Jackson K.; Masao, Fidelis T. (Journal of Human Evolution, 2016)
Keywords: Ngorongoro fan apron; Oldowan; Paleoecology; Phytoliths; Pleistocene landscape

In situ chalcophile and siderophile element behavior in sulfides from moroccan middle atlas spinel peridotite xenoliths during metasomatism and weathering - Westner, Katrin; Beier, Christoph; Klemd, Reiner; Osbahr, Inga; Brooks, Nadine (Minerals, 2019)
In situ chalcophile and siderophile major and trace elements were analyzed in sulfides from eight Moroccan Middle Atlas lherzolite xenoliths using electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The sulfides occur enclosed in primary silicates, interstitial in the peridotite matrix, and associated with glass-bearing melt pockets. Monosulfide solid solutions are enriched in these xenoliths relative to pentlandite and intermediate solid solutions. Regardless of the textural occurrence, sulfide platinum-group element (PGE) patterns are distinguished into residual ([Pd/Ir]N < 1 and [Pt/Pd]N > 1 or [Pt/Pd]N < 1), melt-like ([Pd/Ir]N > 1), and unfractionated patterns. The coexistence of both residual and melt-like PGE signatures on a cm scale in a single sample implies that sulfides may record initial depletion and subsequent re-enrichment more effectively than constituent silicates do. Chalcophile and siderophile trace elements other than the PGEs are fractionated between the precipitated sulfide phases, but do not vary systematically with the PGE signatures, suggesting that the PGEs are comparatively sensitive to melting and depletion. In addition, Fe-rich hydroxides generated by sulfide breakdown due to atmospheric weathering display PGE systematics almost identical to their precursor sulfides, implying that they may be reliable tracers of mantle processes even after extensive weathering.
CRIS-Team Scopus Importer:2019-06-21
Keywords: Metasomatism; Middle atlas; Platinum-group elements; Subcontinental lithospheric mantle; Sulfides; Xenoliths

In situ decrease in rhodolith growth associated with Arctic climate change - Teichert, Sebastian; Reddin, Carl James; Wisshak, Max (Global Change Biology, 2024)
Abstract Rhodoliths built by crustose coralline algae (CCA) are ecosystem engineers of global importance. In the Arctic photic zone, their three-dimensional growth emulates the habitat complexity of coral reefs but with a far slower growth rate, growing at micrometers per year rather than millimeters. While climate change is known to exert various impacts on the CCA's calcite skeleton, including geochemical and structural alterations, field observations of net growth over decade-long timescales are lacking. Here, we use a temporally explicit model to show that rising ocean temperatures over nearly 100 years were associated with reduced rhodolith growth at different depths in the Arctic. Over the past 90 years, the median growth rate was 85 μm year−1 but each °C increase in summer seawater temperature decreased growth by a mean of 8.9 μm (95% confidence intervals = 1.32–16.60 μm °C−1, p < .05). The decrease was expressed for rhodolith occurrences in 11 and 27 m water depth but not at 46 m, also having the shortest time series (1991–2015). Although increasing temperatures can spur plant growth, we suggest anthropogenic climate change has either exceeded the population thermal optimum for these CCA, or synergistic effects of warming, ocean acidification, and/or increasing turbidity impair rhodolith growth. Rhodoliths built by calcitic CCA are important habitat providers worldwide, so decreased growth would lead to yet another facet of anthropogenic habitat loss.<br

In situ decrease in rhodolith growth is associated with Arctic climate change - Teichert, Sebastian; Reddin, Carl; Wisshak, Max (13th International Symposium on Fossil Algae, 2024)
Rhodoliths built by crustose coralline algae (CCA) are ecosystem engineers of global importance. In the Arctic photic zone, their three-dimensional growth emulates the habitat complexity of coral reefs but with a far slower growth rate, growing at micrometres per year rather than millimetres. While climate change is known to exert various impacts on the CCA’s calcite skeleton, including geochemical and structural alterations, field observations of net growth over decade-long timescales are lacking. Here, we use a temporally-explicit model to show that rising ocean temperatures over nearly 100 years were associated with reduced rhodolith growth at different depths in the Arctic. Over the past 90 years, the median growth rate was 85 µm yr-1 but each °C increase in summer seawater temperature decreased growth by a mean of 8.9 µm (95% CIs = 1.32 - 16.60 µm °C-1, p < 0.05). The decrease was expressed for rhodolith occurrences in 11 and 27 m water depth but not at 46 m, also having the shortest time series (1991 – 2015). Although increasing temperatures can spur plant growth, we suggest anthropogenic climate change has either exceeded the population thermal optimum for these CCA, or synergistic effects of warming, ocean acidification, and/or increasing turbidity impair rhodolith growth. Rhodoliths built by calcitic CCA are important habitat providers worldwide, so decreased growth would lead to yet another facet of anthropogenic habitat los
Keywords: calcification; global warming; ecosystem engineers; micro-computed tomography; rhodoliths

In situ gamma radiation measurements in the Neoproterozoic rocks of Sirohi region, NW India - Scharfenberg, Lars; de Wall, Helga; Schöbel, Stefan; Minor, Alexander; Maurer, Marcel; Pandit, Manoj K.; Sharma, Kamal K. (Journal of Earth System Science, 2015)
Natural gamma ray measurements using a portable device were performed at 157 sites in the area around Sirohi town and Sindreth village in Rajasthan (NW India). This region comprises sedimentary rocks, metasediments, granites and gneisses that bear characteristic GR dose values and U/Th ratios corresponding with their specific geological history. A-type Malani granites and rhyolitic derivates, also referred as high heat production granites, show distinct differences as compared to the S-type Erinpura and Balda granites, most prominent in a high Th content of the former (up to 90 ppm). Sedimentary rocks in the Sirohi and Sindreth area are variable in their signatures reflecting their variable source rocks. In the area between the Balda and Paladi villages, northeast of Sirohi, measurements in vicinity of a N-S running shear zone, have shown U enrichment up to 8 ppm. This shear zone has been synkinematically mineralized with quartz and shows evidence of fluid infiltration into the host rocks in the vicinity of the shear zone. Erinpura granites have been altered due to fluid activity and show a light depletion of K (3.96%) and Th (20.11 ppm) as compared to the unaltered rocks (K, 4.06; Th 24.46 ppm). Enrichment of U (with a mean value of 13 ppm) has also been recorded in the lower clastic unit of the Sindreth Basin, especially within gritty conglomerates wherein migration and precipitation along fault planes is proposed.
Keywords: Gamma ray spectrometry; Neoproterozoic; uranium; Sirohi; Sindreth; NW India

In situ gamma radiation measurements on Variscan granites and inferred radiogenic heat production, Fichtelgebirge, Germany - Scharfenberg, Lars; de Wall, Helga; Bauer, Wolfgang (Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 2016)
Granites constitute a major part of the Variscan basement exposed in N Bavaria. It can be assumed that this granitic terrain continues west of the Franconian Fault and forms the basement of the Permo-Mesozoic sedimentary platform (Franconian Basin). This region bears a distinct geothermal anomaly and is currently evaluated for its geothermal potential. Granites are heat-producing bodies in the earth’s crust due to radioactive decay of enriched elements and buried granitic bodies are specified as targets for geothermal prospection. In order to assess the natural gamma-ray emissions and to infer element concentrations of radioelements in-situ measurements are conducted on outcrops in the Fichtelgebirge (with 302 single measurements in total) using a portable measurement device. Here, two granite complexes of different ages are exposed, which are regarded as possible analogues for buried granites in the Franconian Basin. The Older Intrusive Complex (OIC) with intrusion ages around 325 Ma (“Weißenstadt- Marktleuthen Massif”) has a root zone in its eastern part; a Younger Intrusive Complex (YIC) with intrusion ages around 295 Ma has a root zone near the Franconian Line. Furthermore spectral gamma-ray logs down to 1390 m from an 1835 m deep drill hole near Weißenstadt were analysed. The granites of the Fichtelgebirge show definite differences in their U and Th concentrations, between and within the two complexes (OIC, YIC). One influencing factor is the differentiation of the magma with a general decrease in the thorium concentration and increase in the uranium concentrations. Th/U ratios of biotite granite from the upper section (<928 m) of the Weißenstadt borehole correlates well with the G1 of the OIC. In the lower part of the borehole (>928 m) the Th/U ratio shows best correlation with the G3 granite of the YIC exposed in outcrops of the Ochsenkopf, Waldstein and Kornberg granites. The calculated heat production of the granites ranges between 4.4 to 7.6 μW/m3. Granites of the Fichtelgebirge can therefore be ranked as “moderately heat producing”. The need for further studies to estimate the potential increase in heat flow for the Franconian Basin for assumed bodies of heat producing granite in the covered basement is highlighted.
Keywords: natural gamma radiation; granites; heat production; Fichtelgebirge; Germany

In situ incubation of iron(II)-bearing minerals and Fe(0) reveals insights into metabolic flexibility of chemolithotrophic bacteria in a nitrate polluted karst aquifer - Visser, Anna-Neva; Martin, Joseph D.; Osenbrück, Karsten; Rügner, Hermann; Grathwohl, Peter; Kappler, Andreas (Science of the Total Environment, 2024)
Groundwater nitrate pollution is a major reason for deteriorating water quality and threatens human and animal health. Yet, mitigating groundwater contamination naturally is often complicated since most aquifers are limited in bioavailable carbon. Since metabolically flexible microbes might have advantages for survival, this study presents a detailed description and first results on our modification of the BacTrap© method, aiming to determine the prevailing microbial community's potential to utilize chemolithotrophic pathways. Our microbial trapping devices (MTDs) were amended with four different iron sources and incubated in seven groundwater monitoring wells for ∼3 months to promote growth of nitrate-reducing Fe(II)-oxidizing bacteria (NRFeOxB) in a nitrate-contaminated karst aquifer. Phylogenetic analysis based on 16S rRNA gene sequences implies that the identity of the iron source influenced the microbial community's composition. In addition, high throughput amplicon sequencing revealed increased relative 16S rRNA gene abundances of OTUs affiliated to genera such as Thiobacillus, Rhodobacter, Pseudomonas, Albidiferax, and Sideroxydans. MTD-derived enrichments set up with Fe(II)/nitrate/acetate to isolate potential NRFeOxB, were dominated by e.g., Acidovorax spp., Paracoccus spp. and Propionivibrio spp. MTDs are a cost-effective approach for investigating microorganisms in groundwater and our data not only solidifies the MTD's capacity to provide insights into the metabolic flexibility of the aquifer's microbial community, but also substantiates its metabolic potential for anaerobic Fe(II) oxidation.
CRIS-Team Scopus Importer:2024-04-05
Keywords: Chemolithotrophic growth; Corrosion; Karst groundwater; Nitrate; Nitrate-reducing Fe(II) oxidation

In-situ laboratory X-ray diffraction applied to assess cement hydration - de Matos, Paulo R.; Andrade Neto, José S.; Jansen, Daniel; De la Torre, Angeles G.; Kirchheim, Ana Paula; Campos, Carlos E.M. (Cement and Concrete Research, 2022)
In-situ X-ray diffraction (XRD) is a powerful tool to assess the hydration of cementitious materials, providing time-resolved quantitative analysis with reasonable accuracy without disturbing sample. However, the lack of guidelines and well-established procedures for data collection and analysis is the limiting factor for spreading this technique. This paper discussed using in-situ laboratory XRD to assess cement hydration. The first part was dedicated to a literature review on the topic. Then, experimental strategies were discussed, and recommendations related to the data analysis routine were drawn; the advantages and limitations of this technique were also discussed. We can conclude that the critical factors for a successful analysis are the choice of an adequate experimental setup with good statistics and low measurement time, the proper consideration of different amorphous contributions in the XRD pattern, and a good data analysis routine. Independent techniques are highly recommended to support the in-situ XRD data.
CRIS-Team Scopus Importer:2022-10-07
Keywords: Cement; Hydration; In-situ XRD; Laboratory XRD; X-ray diffraction

In situ pH-Wert-Messungen Mischungen aus Calciumaluminatzement mit Calciumsulfat - Schmid, Markus; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Göbbels, Matthias; Brandes, Marc; Johannes, Hans Hermann; Kowalsky, Wolfgang (European Journal of Mineralogy, 2005)
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LM.insitu_9

In-situ trace element and Fe-isotope studies on magnetite of the volcanic-hosted iron ore deposits in the Western Tianshan, NW China - Günther, Thomas; Klemd, Reiner; Horn, Ingo; Zhang, Xi (DMG-Jahrestagung2016, 2016)

In-situ trace element and Fe-isotope studies on magnetite of the volcanic-hosted Zhibo and Chagangnuoer iron ore deposits in the Western Tianshan, NW China - Günther, Thomas; Klemd, Reiner; Zhang, Xi; Horn, Ingo; Weyer, Stefan (Chemical Geology, 2017)
Keywords: Fe-isotopes; IOCG-Kiruna type; Magnetite trace elements; Skarn; Tianshan; Zhibo & Chagangnuoer iron ore deposit

In-situ trace element and S isotope systematics in pyrite from three porphyry-epithermal prospects, Limnos Island, Greece - Börner, Frederik; Keith, Manuel; Bücker, Jonas; Voudouris, Panagiotis; Klemd, Reiner; Haase, Karsten; Kutzschbach, Martin; Schiperski, Ferry (Frontiers in Earth Science, 2022)
Porphyry-epithermal systems associated with high-K calc-alkaline to alkaline igneous host rocks may be prospective for the recovery of Te among related elements like Cu, Ag, and Au. Limnos Island, as part of the Tethyan magmatic belt, is such an example, where (telescoped) porphyry-epithermal mineralization is accompanied by different alteration-styles reflecting various hydrothermal processes. Here, we present in-situ S isotope and trace element data of pyrite, which records the fluid evolution from the early porphyry to the late epithermal stage in three distinct prospects (Fakos, Kaspakas, Sardes) on Limnos Island. Pyrite in the sericitic alteration of Fakos mainly formed from single-phase magma-derived fluids lacking evidence for phase separation, as reflected by relatively constant δ34S (about −4‰) and Co/Ni (0.1-1) values. By contrast, in the sericitic alteration of Kaspakas and the following epithermal stages, an influence of boiling is implied by negative δ34S values to −15‰, significant intergrain δ34S variations (>3‰), highly variable Co/Ni (100-0.01) and As/Co (10-0.001) in pyrite. Higher δ34S values (above −4‰) in porphyry pyrite from Sardes and partly in the other two hydrothermal systems are related to mixing between magmatic S, and S which was transported through deeply circulated seawater and/or meteoric water. We propose that fluid-rock interaction buffered the pH to higher values, which enhanced the solubility of Au and Te. Subsequent boiling processes caused the Au deposition, whereas Te partitioned into the vapor and finally precipitated upon condensation into meteoric water. This process is accompanied by continuous cooling during fluid ascent from 780°C to <300°C, as indicated by increasing Sb, Tl, and Pb in pyrite from the porphyry to the epithermal stage. Consequently, the in situ δ34S and trace element analysis allows to constrain the depositional environment of economic metals like Au and Te in porphyry-epithermal prospects.
CRIS-Team Scopus Importer:2022-11-04
Keywords: in-situ d34S analysis; LA-ICP-MS; Limnos Island; pyrite; telescoped porphyry-epithermal; tellurium–Te

In-situ Untersuchung der frühen PZ-Hydratation - Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Schmitt, Dirk; Degenkolb, Matthias; Holland, Uwe (Tagungsbericht der 16. Internationalen Baustofftagung ibausil, 2006)
UnivIS-Import:2015-04-16:Pub.2006.nat.dgeo.IGM.LM.insitu

In situ Untersuchungen phasenspezifischer und mikrostruktureller Eigenschaften von Portlandzementen - Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Schmitt, Dirk; Degenkolb, Matthias; Holland, Uwe (GDCh-Monographien, 2004)
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.LM.insitu

In-situ XRD investigation of the influence of PDADMAC on ettringite formation in cement systems - Jansen, Daniel; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hergeth, Wolf Dieter; Härzschel, Reinhard (Zeitschrift für Kristallographie, Supplement, 2009)
Since polymers are known to be responsible for the emergence of important properties and the microstructure in mortar systems, our focus was on the influence of the polymer PDADAC on cement hydration. The examinations were focused specifically on the formation of the phase ettringite which is generated during the hydration of Ordinary Portland Cement (OPC). The investigations of the formation of ettringite in the presence of PDAMAC were carried out by means of X-ray diffraction analysis in combination with Rietveld refinement. During hydration of OPC in the presence of low PDADMAC concentrations no significant changes of the ettringite lattice parameters could be determined. After synthesis of pure ettringites only a very small increase of the lattice parameter a occurs, likely due to chloride incorporation. © by Oldenbourg Wissenschaftsverlag, München.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.insitu_2
Keywords: Ettringite; Lattice parameters; OPC; PDADMAC

In-situ XRD study of the temperature-dependent early hydration of calcium aluminate cement in a mix with calcite - Goergens, Julian; Manninger, Tanja; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2020)
In the present work the hydration of white CAC, inert alumina-filler and CaCO3 was investigated at different temperatures with in-situ XRD. Experiments were performed at 10 °C, 23 °C, 40 °C and 60 °C. Overcoming or mitigating the phenomena of calcium aluminate hydrate conversion by adding reactive additives to calcium aluminate cement is often described in literature. When a sufficient amount of calcite is added, carbonate-AFm (monocarbonate and hemicarbonate) is expected to be the dominant hydrate phase. Calcite however, acts as an inert filler and barely influences the calcium aluminate hydration products at 10 °C. With rising temperature monocarbonate contents increase as well as the reaction rate of cement phases. At 60 °C minor amounts of C3AH6 precipitate during the early hydration. Special attention is given to the role of CAH10 and C2AHx during hydration. While CAH10 is dominant at 10 °C, C2AHx precipitates in a temperature range between 23 and 60 °C as a precursor phase for carbonate-AFm phases. These are not found at 10 °C, which is probably due to the lack of the precursor phase (C2AHx). The hydration of the mix at 10 °C with an initial addition of C2AHx shows that carbonate-AFm-phases can be precipitated in addition to CAH10 during the first 96 h.
CRIS-Team Scopus Importer:2020-06-30
Keywords: Calcite (D); Calcium aluminate cement (D); Hydration (A); X-ray diffraction (B)

Instantaneous healing of micro-fractures during coseismic slip: Evidence from microstructure and Ti in quartz geochemistry within an exhumed pseudotachylyte-bearing fault in tonalite - Bestmann, Michel; Pennacchioni, Giorgio; Mostefaoui, Smail; Göken, Mathias; de Wall, Helga (Lithos, 2016)
Exhumed faults within the tonalitic Adamello pluton (Southern Alps) were seismic at depth as indicated by the presence of pseudotachylytes (solidified friction-induced melts). During cooling of tonalite, early-formed joints were first exploited by localized ductile shear zones associated with deposition of quartz veins (at similar to 500 degrees C), and later by pseudotachylyte-bearing cataclastic faults (at similar to 250-300 degrees C ambient temperature). Adjacent to pseudotachylytes, quartz of the host tonalite shows pervasive thin (1-10 mu m wide) healed micro-fractures and ultra-fine (1-2 mu m grain size) recrystallized aggregates along micro-shear zones. Under cathodoluminescence (CL) the healed micro-fractures have a darker gray shade than the host "magmatic" quartz that reflects a change in Ti concentrations ( [Ti]) as indicated by NanoSIMS measurements. [Ti] vary from 35-55 ppm in the CL-lighter host quartz to 10-13 ppm along the CL-darker healed micro-fractures. These [Ti] were inherited by the ultra-fine recrystallized aggregates that overprinted both the magmatic quartz and the healed micro-fractures during the high temperature transient related to frictional seismic slip. Based on Ti-in-quartz thermometry, we infer that micro-fracture healing occurred at higher temperatures than the ambient temperatures of faulting (250-300 degrees C at 0.2 GPa), for which [Ti] <1 ppm would be expected. Micro-fracture healing can be ascribed to the stage of seismic slip of faults on the basis of the observation that: (i) they are absent in the host rock surrounding high-T quartz veins un-exploited by faults; and (ii) they locally occur at the tip of pseudotachylyte injection veins filling new fractures developed during the propagation of the earthquake rupture. The relatively high [Ti] of micro-fractures are therefore interpreted to reflect quartz healing by a fluid overheated during the initial stages of frictional seismic slip and escaping from fault surface through the damage zone. This suggests that, in the presence of fluids, thermal pressurization of the fault did not occur and did not prevent frictional melting. The small-scale microstructures and geochemistry of quartz in the wall of the studied paleo-seismic fault record a complex deformational history, referable to the short-lived (on the order of 10(4) s) thermal anomaly induced by frictional seismic slip, that includes both micro-fracture healing and recrystallization. This microstructural assemblage of the natural exhumed fault provides a key for understanding the mechanics of an earthquake source. (c) 2016 Elsevier B.V. All rights reserved.
Keywords: Titanium in quartz; Cathodoluminescence; Quartz deformation; Pseudotachylyte; NanoSIMS; Micro-fracturing

Instantiations of Multiscale Kinship in Pressing‐Defect Distributions in Yttria‐Stabilized Zirconias by Powder Partitioning - Pereira, Raíssa Monteiro; Lohbauer, Ulrich; Schulbert, Christian; Göken, Mathias; Wurmshuber, Michael; Campos, Tiago Bastos Moreira; Thim, Gilmar Patrocínio; Mieller, Björn; Belli, Renan (Advanced Engineering Materials, 2024)
Modern dry pressing of ceramic powders using spray-dried granulates cannot avoid the occurrence of defects related to persisting inter- and intra-granulate interstitial voids. These constitute the parent defect size population limiting the application of polycrystalline ceramics in high-stress conditions. The mitigation of such defects could widen the range of application in technical and biomedical engineering, reduce the safety range for design, and extend the lifetime of components. Herein, the Weibull size-effect on strength in size-partitioned Yttria-stabilized zirconias (YSZ) feedstocks is used to explore the viability of changing the density distribution of granulate sizes as an effective strategy to obtain a denser particle packing that could reduce the size distribution of strength-limiting pressing defects. In a direct assessment of critical defect size using multiscale strength testing with a dataset of ≈1300 values, the success of such an approach in increasing the strength reliability for small volume components is demonstrated, along with its ultimate failure in altering the defect size distribution in sintered YSZ ceramics across several length scales. Finally, it is shown that granule morphology (spherical or dimpled) fails to affect the defect density and size distribution in YSZ ceramics.<br
Keywords: powder processing; pressing defects; strength; Weibull statistics; zirconia ceramics

Integrated bio- and lithofacies analysis of coarse-grained, tide-dominated deltaic environments across the Cretaceous/Paleogene boundary in Patagonia, Argentina - Scasso, R. A.; Aberhan, M.; Ruiz, L.; Weidemeyer, S.; Medina, F. A.; Kießling, Wolfgang (Cretaceous Research, 2012)
Four facies associations representing, from sea to land, namely (1) tidal bars in distal delta front, (2) proximal tidal bar complexes, (3) tidal channel and tidal flat deposits, and (4) multi-episodic, tide-influenced channels, resulted from the bio- and lithofacies analysis of the siliciclastic Cretaceous/Paleogene Lefipán Formation (Patagonia, Argentina). Lithofacies analysis indicates the existence of coarse-grained, tide-dominated deltas fed with sediments of braided rivers, a rare type of delta that was developed at the western margin of a large marine embayment during the Cretaceous/Paleogene (K/Pg) boundary interval. Differences in taxonomic composition and ecological structure of the biofacies revealed variations in environmental factors, with salinity exerting the principal influence on biofacies. Salinity varied from oligohaline and mesohaline in the deltaic, high-stress environments, as typified by monospecific bivalve assemblages, to diverse and trophically more complex associations, indicating more normal marine and stable conditions. Thus, the biofacies provided an independent tool to check the results of the lithofacies analysis in complex transitional environments. A comparison of Maastrichtian and Danian faunas suggests that the K/Pg boundary event disrupted the stable Maastrichtian communities via the extinction of dominating species, leading to less diverse but more varied Danian assemblages. A shift in trophic structure to increased percentages of deposit-feeders in the Danian was not a direct consequence of impact-related environmental perturbations at the boundary in the studied onshore environment. This contrasts with previous studies of siliciclastic offshore settings, where such a shift in trophic composition was interpreted as the consequence of a productivity crisis at the boundary. © 2012 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LP.integr
Keywords: Biofacies; K/Pg; Lithofacies; Patagonia; Salinity; Tide-dominated delta

Integrated bio-chemostratigraphy of Lower and Middle Triassic marine successions at Spiti in the Indian Himalaya: Implications for the Early Triassic nutrient crisis - Sun, Yadong; Richoz, Sylvain; Krystyn, Leopold; Grasby, Stephen E.; Chen, Yanlong; Banerjee, D.; Joachimski, Michael (Global and Planetary Change, 2021)
In this paper we study the Lilang Super Group in the Spiti area, Indian Himalaya to understand environmental changes in the aftermath of the end-Permian mass extinction. We focus on the Mikin and Kaga Formations, which span the Induan to Ladinian stages of the Lower and Middle Triassic. These strata formed on the southern mid-palaeolatitude margin of East Gondwana and are interpreted as condensed, mixed carbonate – siliciclastic ramp deposits that deepened distally. Carbon isotope ratios of carbonate (δ13Ccarb) show an increase from −2.6 to 0‰ from the Griesbachian substage to the Dienerian-Smithian transition, followed by a negative shift to −3‰ in the Smithian substage and a large positive excursion from −3.0 to 3.5‰ across the Smithian-Spathian boundary. A short negative shift to −1.0‰ occurred in the early Spathian substage, and is followed by a positive trend from −1.0 to 1.0‰ in the Middle Triassic, with several minor excursions occurring during the Aegean substage. Carbon isotope ratios of total organic carbon (δ13Corg) co-vary with δ13Ccarb, suggesting that both proxies represent the original isotopic signatures. Sedimentary and palaeontological evidence, as well as trace metal geochemistry (Mo/Al ratio), indicate anoxic conditions developed from the late Griesbachian to the Dienerian substages, and dysoxic to probably fully oxic conditions from the late Dienerian substage onward. Anoxic conditions only very briefly reoccurred in the late Smithian substage. Ti/Ca and Zr/Al ratios suggest a consistently high terrestrial input in the first three substages of the Early Triassic, followed by a decrease across the Smithian–Spathian boundary. Thus, in the Spiti area, the positive δ13Ccarb excursion across the Smithian–Spathian boundary is recorded in generally well‑oxygenated sediments and coincides with a decrease in terrestrial input. While evidence for enhanced weathering is lacking, observations are strongly at odds with studies postulating eutrophication as a universal kill mechanism for the Smithian–Spathian crisis. The strata in the Spiti area contain an Early Triassic gap in phosphorite deposition indicating a 5 Myr waning of coastal upwelling in an otherwise persistent (>100 Myr) upwelling zone of the East Gondwana margin. The phosphorite gap suggests low P availability, low rates of organic matter degradation, and a reduction in nutrient exchange between deep and surface water masses. Altogether, the phosphorite gap, the paucity of sessile and filtering fauna in oxygenated waters, and low organic carbon burial rates indicate a collapse in marine productivity in the aftermath of the end-Permian mass extinction.<br

Integrated Cambrian biostratigraphy and carbon isotope chemostratigraphy of the Grönhögen-2015 drill core, Öland, Sweden - Ahlberg, Per; Lundberg, Franz; Erlström, Mikael; Calner, Mikael; Lindskog, Anders; Dahlquist, Peter; Joachimski, Michael (Geological Magazine, 2019)
Keywords: Scandinavia; trilobites; Borgholm Formation; carbon isotope excursion; Alum Shale Formation; agnostoids

Integrating EU project Aqua Terra - Barth, Johannes; et al. (Grundwasser, 2006)

Integrating Fossil Observations Into Phylogenetics Using the Fossilized Birth-Death Model - Wright, April M.; Bapst, David W.; Barido-Sottani, Joelle; Warnock, Rachel (Annual Review of Ecology Evolution and Systematics, 2022)
Over the past decade, a new set of methods for estimating dated trees has emerged. Originally referred to as the fossilized birth-death (FBD) process, this single model has expanded to a family of models that allows researchers to coestimate evolutionary parameters (e.g., diversification, sampling) and patterns alongside divergence times for a variety of applications from paleobiology to real-time epidemiology. We provide an overview of this family of models. We explore the ways in which these models correspond to methods in quantitative paleobiology, as the FBD process provides a framework through which neontological and paleontological approaches to phylogenetics and macroevolution can be unified. We also provide an overview of challenges associated with applying FBD models, particularly with an eye toward the fossil record. We conclude this review by discussing several exciting avenues for the inclusion of fossil data in phylogenetic analyses.
CRIS-Team WoS Importer:2022-12-30

Integration of darriwilian (Middle ordovician) δ13Corg chemostratigraphy with graptolite biostratigraphy in the classical Röstånga area in northwestern Scania (southern Sweden) - Bergström, Stig M.; Ahlberg, Per; Maletz, Jörg; Lundberg, Frans; Joachimski, Michael (Estonian Journal of Earth Sciences, 2020)
The largely covered Middle Ordovician succession in the classic geological Röstånga area in northwestern Scania has not been studied for some 80 years. A new drill core through a succession ranging from the lower–middle Darriwilian to the lower Sandbian has provided a unique opportunity to investigate the graptolite biostratigraphy and the δ13Corg chemostratigraphy, and clarify their stratigraphic relations, through this 90 m thick interval, which is developed within a black shale facies. The lithology, biostratigraphy and chemostratigraphy are closely similar to those of the coeval strata in the Fågelsång area, southcentral Scania, including the presence of the Fågelsång Phosphorite, which was previously unrecorded in the Röstånga area. The new data are particularly important in providing evidence of the relations between graptolite biostratigraphy and δ13Corg chemostratigraphy. The Fågelsång3 and Röstånga2 drill core successions are currently the only Darriwilian sequences in the world where these relations have been well established.
CRIS-Team Scopus Importer:2020-06-16
Keywords: Baltoscandia; Black shale; Chemostratigraphy; Ordovician; Outer shelf; Phosphorite; Regional correlation

Integration of Darriwilian (Middle Ordovician) δ13Corg chemostratigraphy with graptolite biostratigraphy in the classical Röstånga area in northwestern Scania (southern Sweden) - Bergström, Stig M.; Ahlberg, Per; Maletz, Jörg; Lundberg, Franz; Joachimski, Michael (Estonian Journal of Earth Sciences, 2020)

Integration of Remote Sensing and Mexican Water Quality Monitoring System Using an Extreme Learning Machine - Arias-Rodriguez, Leonardo F.; Duan, Zheng; Díaz-Torres, José de Jesús; Basilio Hazas, Mónica; Huang, Jingshui; Udhaya Kumar, Bapitha; Tuo, Ye; Disse, Markus (Sensors, 2021)
Remote Sensing, as a driver for water management decisions, needs further integration with monitoring water quality programs, especially in developing countries. Moreover, usage of remote sensing approaches has not been broadly applied in monitoring routines. Therefore, it is necessary to assess the efficacy of available sensors to complement the often limited field measurements from such programs and build models that support monitoring tasks. Here, we integrate field measurements (2013–2019) from the Mexican national water quality monitoring system (RNMCA) with data from Landsat-8 OLI, Sentinel-3 OLCI, and Sentinel-2 MSI to train an extreme learning machine (ELM), a support vector regression (SVR) and a linear regression (LR) for estimating Chlorophyll-a (Chl-a), Turbidity, Total Suspended Matter (TSM) and Secchi Disk Depth (SDD). Additionally, OLCI Level-2 Products for Chl-a and TSM are compared against the RNMCA data. We observed that OLCI Level-2 Products are poorly correlated with the RNMCA data and it is not feasible to rely only on them to support monitoring operations. However, OLCI atmospherically corrected data is useful to develop accurate models using an ELM, particularly for Turbidity (R2 = 0.7). We conclude that remote sensing is useful to support monitoring systems tasks, and its progressive integration will improve the quality of water quality monitoring programs.<br
Keywords: Landsat 8 OLI; Sentinel 2 MSI; Sentinel 3 OLCI; water quality monitoring system; extreme learning machine; support vector regression; inland waters; turbidity; Chlorophyll-a; secchi disk depth

Integrierte Untersuchungen in Böden, Grundwässern, Sedimenten und Flüssen: Anwendungen vom EU-Projekt AquaTerra - Barth, Johannes; et al. (Springer, 2007)

Intensive ocean anoxia and large δ13Ccarb perturbations during the Carnian Humid Episode (Late Triassic) in Southwest China - Zhang, Z.T; Joachimski, Michael; Grasby, Stephen E.; Sun, Yadong (Global and Planetary Change, 2022)
The Carnian Humid Episode (CHE) represents a dramatic dry to wet climate transition in the Late Triassic. Manifestations of this climate shift and its associated biological and environmental responses are not fully understood. Here, we carried out carbonate carbon isotope, trace metal, and pyrite framboid analyses at Wolonggang in southwest China to trace palaeoenvironmental changes during this critical interval. The CHE at Wolonggang is marked by the development of fine laminated carbonaceous siltstones and black shales overlying the intensely bioturbated Zhuganpo limestone deposited in the latest Julian 1. This lithological change is accompanied by two negative δ13Ccarb excursions, a strong enrichment of redox-sensitive trace metals U and Mo, and the development of abundant small pyrite framboids with an average diameter < 5 μm. The sedimentary and geochemical evidence collectively suggest a sharp decrease in carbonate production and a major carbon cycle disturbance, coinciding with the onset of intense ocen anoxia and the mass mortality of burrowing faunas. Unlike other areas in the western Tethys, the aftermath of the CHE at Wolonggang is characterized by long-lasting ocean anoxia, with weak carbonate production persisting at least to the late Tuvalian. This is evidenced by the deposition of finely laminated silty carbonates, marls, and carbonaceous siltstones with rare benthic fossils in the Wayao Formation. Our study suggests that anoxic-euxinic environments widely developed along the southwest margins of the Yangtze Platform and in the Nanpanjiang Basin, probably contributing to the loss of marine faunas during the CHE.<br

Interaction between bimodal volcanism, fluvial sedimentation and basin development in the Permo-Carboniferous Saar-Nahe Basin (south-west Germany) - Stollhofen, Harald; Stanistreet, Ian G. (Basin Research, 1994)
Widespread bimodal-calcalkaline magmatism and contemporaneously active faulting reflect the combined effects of late-orogenic collapse and strike-slip faulting during syn-rift development of the late-Variscan Saar-Nahe Basin. The intrabasinal drainage systems experienced major but differing influences from three prominent styles of volcanic extrusives: extensive basic lava flows; localized acidic domes; and widespread pyroclastic units. Sedimentary sections including basic to intermediate lavas show the transformation of pre-eruptive meandering fluvial systems into lacustrine systems following lava eruptions. These relationships are interpreted in terms of damming of the drainage systems by the topographic barriers represented by the basic lavas themselves. Siliciclastic sediments re-entered and ultimately filled the lakes through prograding, small-scale crevasse channel / mouth bar complexes. Uplift associated with the intrusive / extrusive emplacement of acidic domes affected both the accommodation space and the internal topography of the basin. Following an extrusive pulse, each dome collapse caused the progradation of voluminous volcaniclastic aprons onto the surrounding alluvial plain. Locally, the overload by large volumes of unconsolidated detritus converted the regional meandering drainage system into a braided one. The overall duration of acidic dome activity could have been longer than lo6 years, but was interrupted by repose periods varying probably between a few hundred years to several thousand years. the stratigraphic record. Fine-grained ashes of phreatoplinian eruptions were spread widely within the basin and overloaded streams in the area of fallout. Rapid reworking of huge amounts of unconsolidated material supplied an abundance of volcanic detritus, which tended to fill topographic lows that were usually fault-controlled. The relationships between basin evolution, intrabasinal volcanism and contemporaneously active faulting, identified in the Saar-Nahe Basin, are important. They emphasize and further the understanding of how similar volcanic products in sedimentary basins worldwide impacted on the depositional system.
UnivIS-Import:2015-03-05:Pub.1994.nat.dgeo.IGM.LG.intera

Interaction between gravity- driven listric normal fault linkage and their hanging wall rollover development: a case study from western Niger Delta, Nigeria. - Fazli Khani, Hamed; et al. (Geological Society of London, Special Publications, 2016)

Interaction of silicate and aluminate reaction in a synthetic cement system: Implications for the process of alite hydration - Bergold, Sebastian; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2017)
Synthetic cement with different sulfate additions is investigated by means of heat flow calorimetry and quantitative in-situ XRD. This study especially analyses different sulfate additions between a typical undersulfated and a properly sulfated white Portland cement. A series of sulfate additions was monitored, and the interference of aluminate and silicate reaction was observed. This interference has never received closer examination before. It is shown that while interference occurs at different times during hydration, the reaction turnover of all synthetic cements is the same after 48 h. The results indicate that negative effects on silicate hydration are likely due to the precipitation of AFm phases and not an Al-inhibition process. The accelerating effect of sulfate on alite hydration is most likely caused by a seeding effect of the very fine ettringite that has just precipitated, resulting in more substrate surface for C-S-H precipitation in comparison to pure alite paste. © 2017 Elsevier L
Keywords: Ca3SiO5 (D); Calorimetry (A); Hydration (A); Kinetics (A); X-ray diffraction (B)

Interactions between soil, horizontal heat exchangers and environment: the ITER Project outcomes - Di Sipio, Eloisa; Bertermann, David (Der Geothermiekongress DGK 2017, 2017)
Keywords: soil; backfilling material; thermal conductivity; very shallow geothermal energy; environment resources and sustainability

Interactions of zinc(II) complexes with 5′-GMP and their cytotoxic activity - Soldatovic, Tanja V.; Selimovic, Enisa; Smit, Biljana; Asanin, Darko; Planojevic, Nevena S.; Markovic, Snezana D.; Puchta, Ralph; Alzoubi, Basam M. (Journal of Coordination Chemistry, 2019)
The mechanism of substitution from tetrahedral [ZnCl 2 (en)] and square-pyramidal [ZnCl 2 (terpy)] complexes (where en = 1,2-diaminoethane or ethylenediamine and terpy = 2,2′:6′,2′′-terpyridine) by guanosine-5′-monophosphate (5′-GMP) have been investigated by 1 H NMR spectroscopy. The substitution reaction of [ZnCl 2 (terpy)] complex is faster than the reaction of [ZnCl 2 (en)], which was finished after 48 h. Information about the structures of the final products in solution were obtained from the DFT calculations (B3LYP/6-31G(d)) and experimental 1 H NMR data acquired during the course of the reaction. The cytotoxic activity of zinc(II) complexes was tested on human breast cancer cell line MDA-MB-231, human colon cancer cell line HCT-116 and normal human lung fibroblast cell line MRC-5. Both complexes reduced cell viabilities, while [ZnCl 2 (terpy)] was significantly cytotoxic on MDA-MB-231 after 72 h, and HCT-116 after 24 h without dose dependence. The differences in reactivity toward 5′-GMP and cytotoxic activity of Zn(II) complexes may be attributed to the very stable square-pyramidal geometry of [ZnCl 2 (terpy)] in solution, while weak ligand effect of the en compared to the terpy affected slow interaction of tetrahedral [ZnCl 2 (en)] complex with the target bio-molecule.
CRIS-Team Scopus Importer:2019-05-17
Keywords: 1H NMR; anticancer cytotoxic activity; DFT calculations; guanosine-5′-monophosphate; structure-reactivity correlation; Zinc(II) complexes

Interaktionen des Erdkabelsystems SuedLink mit der Kabelumgebung – Bodenkundlich-Technische Aspekte - Bertermann, David; Drefke, Christoph; Stegner, Johannes; Wessolek, Gerd (2020)
Die Dimension des Gesamtvorhabens SuedLink stellt die Vorhabenträger TenneT TSO GmbH und TransnetBW GmbH vor neue Herausforderungen. Sie betreffen vor allem die Länge der Stromverbindung und die Querung von unterschiedlichen Naturräumen und Infrastrukturen. Diese Räume unterscheiden sich durch verschiedene Ausprägungen in Geologie, Boden, Nutzungs- und Wasserverhältnissen und berühren ganz unmittelbar die Interessen der Flächeneigentümer und -nutzer aus den Bereichen Landwirtschaft, Forstwirtschaft, Ökologie und Naturschutz sowie Verkehrs- und Wegebau. Die Vielzahl der örtlich bedingten Unterschiede und Interessenslagen beim Bau des SuedLinks hat zur Folge, dass allgemeingültige Aussagen basierend auf bisherigen Erfahrungen nur bedingt möglich sind. Dies führt zu breiter Kritik, vornehmlich von land- und forstwirtschaftlichen Behörden und Verbandsvertretern, die ihre ortsbezogenen Belange bzgl. Bodenschutz, Nutzungsauswirkungen und -einschränkungen nicht ausreichend berücksichtigt sehen. Aus diesen Gründen haben seit Beginn der Planung für das HGÜ-Erdkabelvorhaben SuedLink die TenneT TSO GmbH und die TransnetBW GmbH den Kontakt zu renommierten Wissenschaftlern gesucht, um den wissenschaftlichen Ansprüchen und Herausforderungen für den Bau des SuedLinks gerecht zu werden. In diesem Buchprojekt werden verschiedene Studien vorgestellt, die sich hauptsächlich mit Bodenfunktionen und deren Auswirkungen auf den Wärmehaushalt des Bodens in der Erdkabelumgebung beschäftigen. In der ersten Auflage wird zu Beginn ein technischer Überblick zum Einbau von erdverlegten HGÜ-Kabeln gegeben und in den weiteren Kapiteln werden hydraulische Einflüsse und der Einfluss bestimmter Nutzpflanzen thematisiert. Außerdem wird die Thermische Bodenclusterung vorgestellt, mit deren Hilfe physikalische Bodeneigenschaften und klimatische Bedingungen für das komplette Untersuchungsgebiet des Erdkabelvorhabens SuedLink georeferenziert betrachtet werden können. Damit können Ansätze und Antworten bezüglich verschiedener bodenkundlicher Fragestellungen zu den Interaktionen des Erdkabelsystems SuedLink mit der Kabelumgebung aufgezeigt werden. In den folgenden Auflagen dieser Studiensammlung sollen weitere in diesem Kontext durchgeführte Studien vorgestellt werden, um so einen umfassenderen Einblick in das System Boden mit HGÜ-Erdkabel zu leiste

Intergrowths between anthophyllite, gedrite, calcic amphibole, cummingtonite, talc and chlorite in a metamorphosed ultramafic rock of the KTB pilot hole, Bavaria - Schmädicke, Esther; et al. (European Journal of Mineralogy, 2003)
Keywords: Anthophyllite; Amphibole-chlorite-talc intergrowths; Chain arrangement faults; Ca-amphibole; Cummingtonite; Chain multiplicity faults; Orientation relationships; Gedrite exsolutions; TEM

Inter‐laboratory Characterisation of Apatite Reference Materials for Oxygen Isotope Analysis and Associated Methodological Considerations - Wudarska, Alicja; Wiedenbeck, Michael; Słaby, Ewa; Lempart-Drozd, Małgorzata; Harris, Chris; Joachimski, Michael; Lécuyer, Christophe; MacLeod, Kenneth G.; Pack, Andreas; Vennemann, Torsten; Couffignal, Frédéric; Feng, Dingsu; et al. (Geostandards and Geoanalytical Research, 2022)
Here we report on the oxygen isotope compositions of four proposed apatite reference materials (chlorapatite MGMH#133648 and fluorapatite specimens MGMH#128441A, MZ-TH, and ES-MM). The samples were initially screened for 18O/16O homogeneity using secondary ion mass spectrometry (SIMS) followed by δ18O determinations in six gas source isotope ratio mass spectrometry laboratories (GS-IRMS) employing a variety of analytical protocols for determining either phosphate-bonded or “bulk” oxygen compositions. We also report preliminary δ17O and Δ’17O data, major and trace element compositions collected using EPMA as well as CO32- and OH- contents in the apatite structure assessed using thermogravimetric analysis and infrared spectroscopy. The repeatability of our SIMS measurements was better than ± 0.25 ‰ (1s) for all four materials that cover a wide range of 103δ18O values between +5.8 and +21.7. The GS-IRMS results show, however, a significant offset of 103δ18O values between the “phosphate” and “bulk” analyses that could not be correlated with chemical characteristics of the studied samples. Therefore, we provide two sets of working values specific to these two classes of analytical methodologies as well as current working values for SIMS data calibration.

Interlaboratory test for chemical analysis of geothermal fluids: A new approach to determine deep geothermal reservoir fluid composition with uncertainty propagation - Verma, Mahendra P.; Izquiedo, Georgina; Barth, Johannes; Rayes-Delgado, Lisette; Chandrasekhar, Trupti; Algabre, Julienne Eve; Caballero, Marianne Antonette C.; Godoy, José Marcus; Sanchez, Mayela; Brusca, Lorenzo; Malimo, Sylvia; Monvoisin, Gael; et al. (Applied Geochemistry, 2022)
A representative fluid sampling of surface geothermal manifestations and its analytical data quality assurance and quality control (QA/QC) are challenging aspects of understanding the geothermal reservoir processes. To achieve these goals, an interlaboratory test for the chemical analyses of ten water samples: one synthetic water, two lake waters (i.e., duplicated), one stream water, and six water samples from two geothermal wells of Los Azufres Geothermal field (LAGF), Michoacan, Mexico, was conducted. The geothermal wells were sampled at four points: (1) total discharge of condensed fluid at the wellhead, (2) separate liquid condensed in the well separator, (3) flushed liquid at the weir box, and (4) separated vapor condensed at the well-separator (data taken from Verma et al., 2022). Sixteen laboratories from ten countries reported their results. The pH, electrical conductivity, Ca2+, Li+, SO42−, B, and Si-total measurements were 8.35 ± 0.04, 12.25 ± 0.53 mS/cm, 25 ± 1 mg/l, 18 ± 1 mg/l, 569 ± 33 mg/l, 320 ± 21 mg/l, and 20.5 ± 0.7 mg/l, which are close to the conventional true values, 8.40, 12.31 mS/cm, 23 mg/l, 19 mg/l, 647 mg/l, 330 mg/l, and 20.0 mg/l, respectively. Analytical errors for major ions, Na+, Cl− and CO2-Total are 17, 21, and 42 percent, respectively; however, the analytical uncertainties are relatively lower, except for CO2-Total (19%). Similarly, the analytical uncertainty for CO2-Total measurements of the lake water sample is 18%. Thus, the analytical method of individual laboratories for CO2-Total measurements needs revision. The NIST Uncertainty Machine web app was used for the stepwise geothermal reservoir fluid composition calculation with uncertainty propagation from the samples collected at different points of a geothermal well. The wellhead fluid sample does not represent the geothermal reservoir fluid, including the sample collected by connecting a portable separator at the wellhead. The samples collected at points 2 and 3 represent equally well for non-volatile species; however, the sample collected at point 2 is a better representative of geothermal reservoir fluid in analyzing the pH and alkalinity values. It is associated with considering the effect of non-condensable gases (CO2, H2S, etc.) liberated at the silencer of the weir box. The geothermal reservoir fluid pH uncertainty, an essential parameter for geochemical modeling, is three to four times the measured fluid pH uncertainty due to the propagation process. Thus, the alkalinity measurement and its calculation procedure of geothermal fluid need revision to understand its correction for the boric, silicic, and other alkalinities.
CRIS-Team Scopus Importer:2022-11-04
Keywords: Geochemical modeling; Geothermal system; Geothermal water; Inter-laboratory test; Los Azufres; NIST Uncertainty machine; Uncertainty propagation

Inter-laboratory test for oxygen and hydrogen stable isotope analyses of geothermal fluids: Assessment of reservoir fluid compositions - Verma, Mahendra P.; van Geldern, Robert; Barth, Johannes; Monvoisin, Gael; Rogers, Karyne; Grassa, Fausto; Carrizo, Daniel; Delgado Huertas, Antonio; Kretzschmar, Thomas; Esther Villanueva-Estrada, Ruth; Godoy, Jose Marcus; Mostapa, Roslanzairi; et al. (Rapid Communications in Mass Spectrometry, 2018)

Interlaboratory test for stable carbon isotope analysis of dissolved inorganic carbon in geothermal fluids - Verma, Mahendra P.; van Geldern, Robert; Carvalho, Matheus C.; Grassa, Fausto; Delgado-Huertas, Antonio; Monvoisin, Gaël; Carrizo, Daniel (Rapid Communications in Mass Spectrometry, 2020)
Rationale: Stable carbon isotope ratios have many applications in natural sciences. In the first worldwide interlaboratory proficiency test, the discrepancies in measured δ13CDIC values of natural waters were up to σ = ±3‰. Therefore, we continued the investigation on the analytical data quality assurance of individual laboratories and internal consistency among laboratories worldwide. Methods: We designed and performed an interlaboratory comparison exercise for δ13C analyses of ten water and two solid samples (Na2CO3, CaCO3), including two synthetic samples prepared by dissolving the carbonates individually. Three laboratories analyzed an additional sample set to assess solution stability, at least one month after the first set analysis period. The δ13C values were measured using dual inlet isotope ratio mass spectrometry (DI-IRMS) or continuous flow (CF)-IRMS. Results: The δ13C values of solid Na2CO3 and its aqueous solution were −5.06 ± 0.21‰ and 5.32 ± 0.24‰, respectively, while the δ13C value of solid CaCO3 was −4.49 ± 0.93‰. Similarly, the lake water has a consistent value (2.45 ± 0.19‰). The δ13C values of geothermal water have a wide dispersion among individual laboratory measurements and among those of different laboratories; however, a trend exists in the δ13C values measured at the three sampling points of each well. Conclusions: The δ13C values of solid Na2CO3 and its solution, and lake water (i.e. DIC concentration samples >100 mg/L carbon) are consistent among all the participating laboratories. The dispersion in the δ13C values of solid CaCO3 is associated with its lower chemical affinity than that of Na2CO3. The poor reproducibility in the δ13C values of geothermal fluids, collected at three points of a geothermal well, despite overall consistent trends regarding their collection points suggests inadequate sample handling (atmospheric CO2 exchange) and/or inappropriate analytical approaches (incomplete H3PO4 acid reaction).
CRIS-Team Scopus Importer:2020-05-02

Internal stratigraphic relationships in the Etendeka Group in the Huab Basin, NW Namibia: Understanding the onset of flood volcanism. - Jerram, Dougal A.; Mountney, Nigel; Holzförster, Frank; Stollhofen, Harald (Journal of Geodynamics, 1999)
The Etendeka Igneous Province in NW Namibia forms the eastern most extent of the Parana-Etendeka Flood Basalt Province and, despite only covering about 5% of the Parana-Etendeka, has been the focus of much interest, due to its extremely well exposed nature. The Huab Basin in NW Namibia forms the focus of this study, and formed a connected basin with the Parana throughout Karoo times (late Palaeozoic) into the Lower Cretaceous. It contains a condensed section of the Karoo deposits, which indicate early periods of extension, and Lower Cretaceous aeolian and volcanic Etendeka deposits, which have their correlatives in the Parana. In the Huab Basin, the volcanic rocks of the Etendeka Group consists of the Awahab and Tafelberg Formations, which are separated by a disconformity. Detailed examination of the Awahab Formation reveals an additional disconformity, which separates olivine-phyric basalts (Tafelkop-type) from basalt/basaltic andesites (Tafelberg-type) marking out a shield volcanic feature which is concentrated in an area to the SE of the Huab River near to the Doros igneous centre. Early volcanism consisted of pahoehoe style flows of limited lateral extent, which spilled out onto aeolian sands of an active aeolian sand sea 133 million years ago. This sand sea is equivalent to the sands making up the Botucatu Formation in the Parana basin. The early expression of flood volcanism was that of laterally discontinuous, limited volume, pahoehoe flows of Tafelkop-type geochemistry, which interleaved with the aeolian sands forming the Tafelkop-Interdune Member basalts. These basalts are on-lapped by more voluminous, laterally extensive, basalt/basaltic andesite flows indicating a step-up in the volume and rate of flood volcanism, leading to the preservation of the shield volcanic feature. These geochemically distinct basalts/basaltic andesites form the Tsuhasis Member, which are interbeded with the Goboboseb and Sprinkbok quartz latite flows higher in the section. The Tsuhasis Member basalts, which form the upper parts of the Awahab Formation, are of Tafelberg-type geochemistry, but are stratigraphically distinct from the Tafelberg lavas, which are found in the Tafelberg Formation above. Thus, the internal stratigraphy of the flood basalt province contains palaeo-volcanic features, such as shield volcanoes, and other disconformities and is not that of a simple layer-cake model. This complex internal architecture indicates that flood volcanism started sporadically, with low volume pahoehoe flows of limited lateral extent, before establishing the more common large volume flows typical of the main lava pile.
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LG.intern

International Symposium on Early Palaeozoic Plaeogeography and Palaeoclimate, September 2004, Erlangen, Germany - Abstracts and Field Guides - Munnecke, Axel; Servais, Thomas; Schulbert, Christian; et al. (2004)
Keywords: Symposium; Early Palaeozoic; Palaeogeography; Palaeoclimate

Interplay of Autogenic and Allogenic Processes On the Formation of Shallow Carbonate Cycles in a Synrift Setting (Lower Pliensbachian, Traras Mountains, NW Algeria) - Belkhedim, Salim; Jarochowska, Emilia; Benhamou, Miloud; Nemra, Abdelkrim; Sadji, Radouane; Munnecke, Axel (Journal of Sedimentary Research, 2019)
Meter-scale shallowing-upward cycles are recorded in many carbonate successions around the world. It is often difficult to recognize whether they represent autocycles, formed through intrinsic controls, or allocycles, resulting from orbital forcing or tectonic movements, or both. Here, we review the criteria used in the identification of the two types of cyclicity and apply them to two newly described lower Pliensbachian outcrops in the Traras Mountains, northwestern Algeria. Throughout the investigation of six sections, the deposits are suggested to have formed in intertidal-supratidal to shallow subtidal environments on a tropical ramp in the Western Tethys. In this area, shallowing-upward small-scale peritidal and subtidal cycles have been shown to be, and are assumed to be, ordered. The carbon isotope data mirror the recorded cycles and indicate different lengths of subaerial exposures. These cycles, in a developed within synrift setting, have been interpreted as produced mainly by autocyclic processes, but interacting with allocyclic factors. Peritidal cycles are thought to be generated by progradation of intertidal and supratidal flats into lagoonal sediments, while subtidal cycles are interpreted to have been controlled by lateral migration of shoals. The impact of the minor fluctuations of eustatic sea level is weakly marked, and only long subaerial exposure can reveal the contribution of these fluctuations to the formation of the recorded cycles. Tectonic movements resulting from spreading of the Tethys arc interpreted to have controlled cycle distribution and thickness at a regional scale. However, synsedimentary tectonic features are rare in the studied area; this suggests that sediment transport would control the thickness and duration of cycles instead of the rate at which accommodation was created.
CRIS-Team WoS Importer:2019-09-20

Intragranular dynamic recrystallization in naturally deformed calcite marble: Diffusion accommodated grain boundary sliding as a result of subgrain rotation recrystallization - Bestmann, Michel; et al. (Journal of Structural Geology, 2003)
Keywords: Calcite; Electron backscatter diffraction (EBSD); Grain boundary sliding; Misorientation; Orientation map; Subgrain rotation recrystallization

Intraplate magmatism and extensional tectonics: an example from Faial Island, Azores - Romer, René; Beier, Christoph; Huebscher, Christian; Haase, Karsten (Goldschmidt2017 Abstract, 2017)
The Azores archipelago formed by the influence of both, an intraplate melting anomaly and a system of ultraslow spreading rift axes. Most recent submarine and subaerial eruptions in the Azores occur along volcanic rift zones and thus, rates and pathways of magma transport as well as magmatic processes are probably controlled by lithospheric extension [1]. We present new petrological and geochemical data providing insights into the interaction between a melting anomaly in the asthenosphere and extensional forces in the lithosphere. Submarine volcanic rift zones like those on the west flank of Faial island were the focus of RV METEOR cruises M113 and M128. Major element compositions, incompatible trace element ratios (e.g. Nb/Zr, Ba/La) and Sr- Nd isotope ratios of lavas from the active Capelinhos rift differ from those of the inactive Condor de Terra rift some 14 km further south. Lavas from the Capelinhos rift zone are chemically similar to the youngest subaerial lavas from Faial. The older subaerial lavas on Faial represent analogues to the geochemically distinct older submarine rift zones south and north of Capelinhos. Thus, magma sources varied with time and fed different volcanic rift zones where the recently active submarine rifts are connected to the magma plumbing system of the subaerial volcanoes. On the basis of Ar-Ar ages [2], seismic profiles, and direct observations of submarine lava formations at Capelinhos we develop a relative chronology of the magmatic evolution of the rift zones. Our model implies that dikes efficiently transport melts along the volcanic rift zones at Faial over length scales of >12 km while plumbing systems orthogonal to the rift axes are distinct over a similar length scale. Mantle source differences between the rift zones may indicate stagnation of melts at different depths during ascent. Thus, we aim to improve the understanding about the interaction between magmatic and tectonic processes by mineral thermobarometry. [1] Galipp et al. (2006) JVGR 55(3–4), 285-306. [2] Beier et al. (2015) GSA Special Papers 511, 27-55.

Intraspecific variability through ontogeny in early ammonoids - de Baets, Kenneth; Klug, Christian; Monnet, Claude (Paleobiology, 2013)
Mollusks in general and ammonoids in particular are known to display a sometimes profound morphological intraspecific variability of their shell. Although this phenomenon is of greatest importance, it has rarely been investigated and quantified. It is especially crucial for taxonomy and incidentally for biodiversity analyses to account for it, because otherwise, the number of described species might exceed that of actual species within any group. Early ammonoids (Early Devonian, Paleozoic) typically suffer from this bias. For instance, most specimens from the same layer and the same region (e.g., the Erbenoceras beds of the Moroccan eastern Anti-Atlas studied here) differ morphologically from each other. Depending on the importance given to certain morphological characters, therefore, one could create a new species for almost every specimen. In this study, we measured nearly 100 such specimens from a restricted stratigraphic interval and quantified their intraspecific variability. There is a variable but strong overlap of the quantified shell characters at most ontogenetic stages, and only two species are here separated rather than the four previously recognized in Morocco. When ontogenetic trajectories of the Moroccan specimens are compared with coeval faunas from other regions (assigned to other species), a strong overlap between the morphospaces occupied by these taxa becomes apparent. The justification of some of these latter species is thus questionable even if their mean values in some conch parameters differ considerably from the mean values of the Moroccan species. Hence, the number of currently valid species of these loosely coiled early ammonoids is probably much too high. Extreme caution must therefore be taken when examining the diversity of groups in which the intraspecific variability is poorly known.

Intraspecific variation and new morphological characters revealed by multimodal imaging analysis on the Late Cretaceous coleoid Dorateuthis syriaca - Rowe, Alison J.; Kruta, Isabelle; Villier, Loïc; Gueriau, Pierre; Radepont, Marie; Belhadj, Oulfa; Müller, Katharina; Jattiot, Romain; Fuchs, Dirk; Clements, Thomas; Charbonnier, Sylvain; Rouget, Isabelle (Acta Palaeontologica Polonica, 2024)
The Cretaceous outcrops of Haqel, Hjoula (Cenomanian) and Sahel Aalma (Santonian) in Lebanon are renowned for their exceptional preservation of coleoid soft tissue in coeval shallow carbonate mud deposits and provide an unmatched opportunity to study many specimens of a single species, Dorateuthis syriaca. Despite being the most abundant coleoid from these localities, the taxon lacks clear, unambiguous diagnostic characteristics of both the gladius, and soft tissue anatomy. The absence of a defined character complex for the species has led to inconsistencies in the literature and the need for a reappraisal. This investigation represents the largest sample of D. syriaca studied with high-resolution, multi-imaging techniques, and has obtained a comprehensive morphological dataset of measurements on this key taxon. This has allowed us to refine some of the character states used to understand the phylogeny of coleoids. Furthermore, we have identified morphological characters that were previously undescribed for the genus, including suckers, axial nerves, and possible retractor muscles, as well as provided confirmation of the circulatory and excretory systems, and an Octobrachia-type digestive system. We also discount the presence of tentacles, tentacular pockets, and hooks within the arm crown, and we show that the species definition of D. syriaca is more complex than expected as our sample suggests intraspecific variability is present in the gladius. We strongly support the hypothesis that it was an 8-armed coleoid that was likely an active visual predator.<br
CRIS-Team Scopus Importer:2025-02-04
Keywords: Coleoidea; Lagerstätte; multimodal imaging; soft tissue preservation; Lebanon

Introduction - Barth, Johannes; et al. (Environmental Pollution, 2007)

Introduction: Fifty years of Paleobiology - Patzkowsky, Mark; Kießling, Wolfgang (Paleobiology, 2025)
Paleobiology was founded 50 years ago to provide an outlet for biological paleontology, with an emphasis on investigating evolutionary patterns and processes that could apply generally across the history of life. While the intellectual and financial prospects for Paleobiology were uncertain in the beginning (Sepkoski 2012; Valentine 2009), this 50th anniversary issue testifies to its overwhelming success. Fifty years of anything well done deserves a celebration. These moments are a time for reflection and a time for imagining future directions. With this introduction, we outline briefly the start of the journal and two landmark anniversary issues, the 10th and the 25th. No special issue can adequately survey all research themes in a field as intellectually rich as paleobiology. However, these anniversary issues offer a snapshot of research directions, and they can trace the shift and expansion of established fields and mark the emergence of new ones. We end by outlining the contributions to the 50th anniversary issue that summarize current themes and future directions for the field.
CRIS-Team Scopus Importer:2025-05-09

Introduction to Applied Mineralogy - Goetze, Jens; Göbbels, Matthias (2023)
This textbook teaches important material and technological fundamentals in various technical systems and applied geoscientific fields. Beginning with the mineralogical characteristics of selected non-metallic raw materials and industrial minerals, this book presents the connections between properties and industrial applications and discusses the environment-relevant aspects as well as problems of biomineralogy. An introduction is given to important mineralogical and physico-chemical aspects of ceramic materials such as silicate ceramics, glass, cement, refractory materials as well as an overview about material synthesis. This makes it the first textbook to present the fundamentals of applied mineralogy as a material-related geoscience in a compact form and to show important bridges to industrial issues and approaches to solutions. It is aimed primarily at undergraduate students of geosciences and materials science, but is also suitable for related disciplines and practical application
Keywords: Mineralogy; Mineral Synthesis; Environmental Mineralogy; Silicate Materials; Non-metallic raw Materials; Biomineralogy; Energy Technology; Rock Quartzite; Refractory Material; High Quartz; Limestone; Metallurgy; Pegmatite; Vulcanite

Invasive floating macrophytes reduce greenhouse gas emissions from a small tropical lake - Attermeyer, K.; Flury, S.; Jayakumar, R.; Fiener, P.; Steger, K.; Arya, V.; Wilken, F.; van Geldern, Robert; Premke, K. (Scientific Reports, 2016)

Inverse response of 231Pa/230Th to variations of the Atlantic meridional overturning circulation in the North Atlantic intermediate water - Süfke, Finn; Schulz, Hartmut; Scheen, Jeemijn; Szidat, Sönke; Regelous, Marcel; Blaser, Patrick; Pöppelmeier, Frerk; Goepfert, Tyler J.; Stocker, Thomas F.; Lippold, Jörg (Geo-Marine Letters, 2020)
This study aims to provide a more detailed understanding of the behavior of 231Pa/230Th under varying ocean circulation regimes. The North Atlantic provides a unique sedimentary setting with its ice-rafted detritus (IRD) layers deposited during glacial times. These layers have been found north of 40° N (Ruddiman Belt) and are most pronounced during Heinrich Stadials. Most of these sediments have been recovered from the deep North Atlantic basin typically below 3000 m water depth. This study reports sedimentological and sediment geochemical data from one of the few sites at intermediate depth of the open North Atlantic (core SU90-I02, 45° N 39° W, 1965 m water depth) within the Ruddiman Belt. The time periods of Heinrich Stadials 1 and 2 of this core were identified with the help of the major element composition by XRF scanning and by IRD counting. Along the core profile, the sedimentary 231Pa/230Th activity ratio has been measured as a kinematic proxy for the circulation strength. The 231Pa/230Th record shows highest values during the Holocene and Last Glacial Maximum, above the natural production ratio of these isotopes. During Heinrich Stadials 1 and 2, when Atlantic meridional overturning circulation was most reduced, the 231Pa/230Th record shows overall lowest values below the production ratio. This behavior is contrary to classical findings of 231Pa/230Th from the northwestern Atlantic where a strong Holocene circulation is associated with low values. However, this behavior at the presented location is in agreement with results from simulations of the 231Pa/230Th-enabled Bern3D Earth system model.
CRIS-Team Scopus Importer:2020-01-21

Investigating an Alpine proglacial sediment budget using field measurements, airborne and terrestrial LiDAR data - Heckmann, Tobias; Haas, Florian; Morche, David; Schmidt, Karl Heinz; Moser, Michael; Leopold, Matthias; Kuhn, Michael; Briese, Christian; Pfeifer, Norbert; Becht, Michael; Rohn, Joachim (Chengdu Symposium on Erosion and Sediment Yields in the Changing Environment, 2012)
Keywords: Airborne LiDAR; Central Alps; Proglacial sediment budget; Terrestrial LiDAR; Tyrol

Investigating the structure of a multiple karst aquifer system and its hydrological process response using high-resolution multi-tracer data - Ji, Huaisong; Chiogna, Gabriele; Chang, Wei; Richieri, Beatrice; Chen, Lin; Luo, Mingming; Guo, Xulei; Huang, Kun (Journal of Hydrology, 2025)
Understanding the hydrogeological structure and hydrogeochemical processes of karst aquifers is critical for groundwater management. This study innovatively integrates drilling, tracer tests, high-resolution monitoring, and multi-isotope techniques (3H, 14C, δD, δ18O) to systematically characterize the spatial heterogeneity of a multiple karst aquifer system. Hydrochemical data was analyzed with the electrical conductivity decomposition method. Multivariate statistical analysis and the ions ratio are used to identify the sources and components of the spring water during storm events. The results indicate that: (1)The upper and lower aquifer systems are composed of limestone and dolomite, respectively, while the intermediate aquifer system is constituted by both limestone and dolomite. The upper and intermediate aquifer systems exhibit conduit flow regimes, whereas the lower aquifer is characterized by fracture flow. The lower aquifers (∼13,862-year residence time) show unique SO42-, Sr2+, F- enrichment and lighter δD/δ18O signatures, reflecting prolonged water-rock interactions. (2) Comparative analyses of ion ratios during storm events in the BLD spring, demonstrate that both limestone and dolomite significantly influence the spring hydrochemistry. The hydrochemistry changes in the spring outlet are caused by dilution and mixing of recharge from limestone and dolomite aquifers, triggered by rainfall. During rainstorm events, the dolomite aquifer is the primary source of recharge. (3) The study establishes a “structure-process-evolution” conceptual model, demonstrating how multi-tracer synergy resolves hydrological complexity in heterogeneous karst systems. Our study highlights the importance of collecting and interpreting high-resolution multi-tracer datasets to unravel the dynamics of hydrological processes in complex multiple karst aquifer systems.
CRIS-Team Scopus Importer:2025-04-04
Keywords: Conductivity decomposition method; High-resolution multi-tracer; Hydrological process; Multiple karst aquifer systems

Investigation of a shotcrete accelerator for targeted control of material properties for 3D concrete printing injection method - Pott, Ursula; Jakob, Cordula; Dorn, Tobias; Stephan, Dietmar (Cement and Concrete Research, 2023)
The efficiency of 3D concrete printing significantly depends on the mortar performance, which can be improved and controlled by adding a shotcrete accelerator. This targeted control is implemented by adding a small accelerator dose to an injection nozzle before extrusion. In this article, a study is conducted on the suitability of the material for this application. For this purpose, a shotcrete accelerated printable mortar is investigated. Comparing physical and physicochemical results leads to an in-depth understanding of the chemical processes and their effects on physical behaviour, which enables a positive assessment of the accelerator for 3D concrete printing injection method.
CRIS-Team Scopus Importer:2023-07-28
Keywords: 3D concrete printing injection method; Cement hydration; Physical material behaviour; Shotcrete accelerator; Suitability study

INVESTIGATION OF DIFFERENT CURING TEMPERATURES ON PHASE CHANGES DURING DRYING OF CASTABLES - Köhler, Andreas; Kuiper, S.; Klaus, S.; Götz-Neunhoeffer, Friedlinde (Unified International Technical Conference on Refractories, UNITECR 2022 - Proceedings, 2022)
In this study, the influence of different curing temperatures on the subsequent phase changes during the drying process of calcium aluminate cement bond castables is presented. A mixture of CAC and alumina was hydrated at different temperatures (5, 23, 40°C), which should represent extreme working conditions during casting. The quantitative phase composition after 48 h of hydration was determined by Rietveld-analysis. Thermogravimetric analysis was also used to characterize the weight loss during heating. The results have shown that above 350 °C all hydrate phases are dehydrated, but that the differently cured samples lead to quite different dehydration processes and phase compositions. Therefore, the cured samples were heated up to 180 °C, as at this temperature the different curing conditions lead to a different dehydration progress. The different starting conditions before drying strongly affect the final phase composition, as well as a different way to get the water-free product. Samples cured at moderate or high temperature lose water over a wider temperature range. In contrast, in samples cured at low temperature, almost all unbound H2O and water in hydrate phases is removed at temperatures below 180 °C.
CRIS-Team Scopus Importer:2024-12-16

Investigation of flow and heat transfer characteristics in fractured granite - Luo, Jin; Qi, Yumeng; Zhao, Qiang; Tan, Long; Xiang, Wei; Rohn, Joachim (Energies, 2018)
Keywords: Flow properties; Fractured rock mass; Heat transfer process; Infrared thermal imaging

Investigation of hydration behavior of Ferrite phase C_6_A_x_F_3-x_ with different Al^3+^-content in mixes with C_3_A and Gypsum using a revised highly efficient isothermal calorimeter - Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Ingrid, Lindner (Proceedings of the 11th International Congress on the Chemistry of Cement, 2003)
UnivIS-Import:2015-03-09:Pub.2003.nat.dgeo.IGM.LM.invest_8

Investigation of shallow geothermal potentials for different types of ground source heat pump systems (GSHP) of Wuhan city in China - Luo, Jin; Luo, Zequan; Xie, Jihai; Xia, Dongsheng; Huang, Wei; Shao, Haibin; Xiang, Wei; Rohn, Joachim (Renewable Energy, 2018)
To ensure techno-economically suitable installation of ground source heat pump (GSHP) systems, thermal and hydrogeological properties of the subsoil need to be investigated. In this paper, the geothermal potential for three types of GSHP installations in the urban area of Wuhan city is assessed based on preliminary geological investigations. The potential for shallow geothermal energy is evaluated for surface water heat pump systems (SWHP), groundwater heat pump systems (GWHP) and ground coupled heat exchanger heat pump systems (GCHP). The mapped shallow geothermal potentials provide essential information for the installation of GSHPs and for the management of geothermal resources of Wuhan city. Furthermore, the heat transfer rates for some typical configured borehole heat exchanger (BHE) are tested by field Thermal Response Tests (TRT). In order to understand the techno-economic feasibility of the GSHPs, different types of the installed systems are measured and analyzed. © 2017 Elsevier Ltd
Keywords: Geothermal energy; Geothermal fields; Geothermal prospecting; Groundwater; Heat exchangers; Heat pump systems; Heat transfer; Information management; Pumps; Soils; Surface waters; Thermodynamic properties; Borehole heat exchangers; Geological investigation; Geothermal potential; Groundwater heat pumps; Hydrogeological properties; Shallow geothermal energies; Techno-economic feasibility; Thermal response test; Geothermal heat pumps; borehole; geothermal energy; heat source; heat transfer; installation; pump; renewable resource; shallow water; subsoil; surface water; urban area; China; Hubei; Wuhan

Investigation of the beta'- to alpha-phase transformation temperature of (Ca1-xMgx)3(PO4)2 solid solutions - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Enderle, Ralph; Göbbels, Matthias (Zeitschrift für Kristallographie, Supplement, 2007)
Tricalcium phosphate Ca3(PO4)2 (TCP), an osteoconductive as well as bioresorbable phase, has found application as bone cement and bone implant material. TCP was found to crystallize in three polymorphic modifications: β-TCP below 1180°C, α-TCP between 1180°C and 1430°C, and α-TCP above 1430°C [1]. It is mainly β-TCP and α-TCP that have gained acceptance in biomedical applications. At the moment β-TCP ceramics are used for non-load-bearing applications in oral surgery. In this investigation we were able to detect an additional but reversible phase transformation from β- to β′-TCP at 1000°C. The influence of partial Mg2+ substitution of Ca 2+ in the solid solution series of β′-TCP (Ca 1-xMgx)3(PO4)2 was determined at 1025°C ± 10°C in air. The temperatures for β′- to α-TCP phase transformation were investigated in a manner differentiated according to the different Mg2+ contents.
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LM.invest
Keywords: Polymorphic modifications; Rietveld refinement; Solid solution; Tricalcium phosphate (TCP); X-ray powder diffraction

Investigation of the Early Cement Hydration with a New Penetration Test, Rheometry and In-Situ XRD - Pott, Ursula; Ehm, Clemens; Jakob, Cordula; Stephan, Dietmar (Rheology and Processing of Construction Materials, 2020)
To gain more information about the relationship between early cement hydration and rheological behavior of the corresponding cement paste, a new penetration test device, with the name “Multipurpose Incremental Loading device” (MILD), has been developed. The construction and the mechanical properties of the device are described in detail. Furthermore, the implementation of a measurement and first results will be discussed, and the new device is compared with the standardized Vicat test. In addition, a comparison of the measurement results with rheological investigations is made and the results of quantitative in-situ XRD and calorimetry are integrated for a deeper understanding. We show that it is possible to get more information about the structure formation with the new device than with the Vicat test. Moreover, a comparison with the rheological properties of a cement paste was done. Both methods show two periods with different rheological behavior. During the first two hours the paste shows a slow increase of viscosity which is followed by a strong increase. The results of the penetration test and the rheometer are linked with the formation of hydration products and the heat flow development. This comparison shows that the link between the two periods is the beginning of the acceleration period. Finally, it is concluded that it is possible to get precise information about the early cement hydration with a penetration test.
CRIS-Team Scopus Importer:2019-10-22
Keywords: Early cement hydration; Penetration test; Phase formation; Rheology

Investigation of the incompatibilities of cement and superplasticizers and their influence on the rheological behavior - Pott, Ursula; Jakob, Cordula; Jansen, Daniel; Neubauer, Jürgen; Stephan, Dietmar (Materials, 2020)
The rheological behavior of cement paste and the improvement of its flowability takes center stage in many research projects. An improved flowability can be achieved by the addition of superplasticizers (SP), such as polycarboxylate ethers (PCE). In order to be able to use these PCEs effectively and in a variety of ways and to make them resistant to changes in the environment, it is crucial to understand the influence of SPs on cement hydration. For that reason, the topic of this paper was the incompatibility of a specific SP and an ordinary Portland cement (OPC). The incompatible behavior was analyzed using rheological tests, such as the spread flow test and penetration test, and the behavior was compared by means of an ultrasound technique and explained by the phase content measured by in-situ X-ray diffraction (XRD) the heat evolution measured by calorimetry, and scanning electron microscope (SEM) images. We showed that the addition of the SP in a high dosage led to a prevention of the passivation of the most reactive and aluminum-containing clinker phases, aluminate and brownmillerite. This induced the aluminate reaction to take place in the initial period and led to an immediate stiffening of the cement paste and, therefore, to the complete loss of workability. The results showed that in addition to the ettringite, which began to form directly after water addition, hemicarbonate precipitated. The fast stiffening of the paste could be prevented by delayed addition of the SP or by additional gypsum. This fast stiffening was not desirable for SPs, but in other fields, for example, 3D printing, this undesirable interaction could be used to improve the properties of printable mortar.
CRIS-Team Scopus Importer:2020-03-27
Keywords: Calorimetry; Hydration; In-situ XRD; Incompatibility of superplasticizer; Penetration; Rheology; SEM; Spread flow test; Ultrasound

Investigation of the influence of groundwater flow on horizontal ground heat exchangers using numerical simulations - Rammler, Mario; Suft, Oliver; Bertermann, David (Hydrological Research Letters, 2025)
In contrast to unsaturated soil conditions, advective heat transport dominates in aquifers. Consequently, groundwater flow can affect the efficiency of geothermal horizontal ground heat exchangers (HGHEs) and the development of downstream thermal plumes. In contrast to deeper geothermal systems, this has not been investigated in detail for HGHEs due to their shallow installation depths. In order to address this issue, in this study, the effects of different groundwater flow conditions on a theoretical unidirectional HGHE were evaluated using the FEFLOW® finite element simulation system. A total of 81 variants with different groundwater levels, flow velocities and flow directions were considered in the numerical simulations. The results showed a significant increase in HGHE efficiency with increasing groundwater level (GWL) and flow velocity. In addition, significantly higher heat gains were obtained when the groundwater flow direction was orthogonal to the HGHE. The lateral spread of the thermal plumes was greatest for orthogonal flow directions, high flow velocities and groundwater levels slightly above the HGHE. The presented FEFLOW® approach was suitable to investigate the effects of different hydraulic subsurface conditions on a unidirectional HGHE and should be vali-dated with real measured data in further research.
CRIS-Team Scopus Importer:2025-03-28
Keywords: advective heat transport; FEFLOW®; groundwater; horizontal ground heat exchangers; numerical simulations

Investigation of the ß-alpha TCP phase transformation in dependence of Mg-content - Götz-Neunhoeffer, Friedlinde; Göbbels, Matthias; Enderle, Ralph (Proc. of the 19th General Meeting of the IMA, 2006)
UnivIS-Import:2015-04-16:Pub.2006.nat.dgeo.IGM.LM.invest

Investigations on introducing Si and Mg into Brownmillerite - A Rietveld Refinement - Neubauer, Jürgen; Kuzel, Hans Jürgen; Sieber, Roland; Ecker, Michael (Cement and Concrete Research, 1996)
Brownmillerite (commonly C4AF) was synthesized in a laboratory furnace. The product was examined by X-ray powder diffraction and the structure was refined by the Rietveld method. Further syntheses were made under various conditions by substituting Fe2O3 by MgO + SiO2 according to the formula C4AF1-xMxSx. All samples were examined by X-ray diffraction and quantified by Rietveld method due to their content of Brownmillerite, C2S and MgO. All results show that the whole SiO2 content could be calculated as C2S. MgO could be partially found as periclase. Brownmillerite shows a shift of lattice parameters according to the solid solution series C6A2F - C2F.
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LM.invest

Investigations on Stability and Long-term Behaviour of AFm Phases at Higher Temperatures by Powder Diffraction Methods - Götz-Neunhoeffer, Friedlinde; Pöllmann, Herbert (Materials Science Forum, 1996)
Immobilisation and solidification of pollutants can be achieved by adding cement to the waste products or by mixing adequate proportions of industrial waste products as flue gas desulfurization products, fly-ashes, contaminated sludges etc. The resulting stabilised product of this treatment is containing different reservoir minerals intimately intergrown with non reactive material. The solidified waste containing the immobilised pollutants itself can be used as an "Inner Barrier System" [1] of a waste dump. For this application the solidification products have to be stable under the physico-chemical conditions in a waste dump. In this study the long-term behaviour of the formed reservoir minerals of the AFm-type (Al2O3-Fe2O3-monophases) was evaluated by X-ray investigations at higher temperatures.
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LM.invest_0
Keywords: AFm Phases; Halogenides; Immobilisation; Lamellar Calcium Ferrate Hydrates; Reservoir Minerals; X-Ray Diffraction at Higher Temperatures

Investigations on the effect of alkalis on C-S-H growth rates and their impact on early C3S hydration rates - Wagner, Daniel; Bellmann, Frank; Neubauer, Jürgen (Cement and Concrete Research, 2023)
In this work, we investigated the influence of alkalis on C-S-H precipitation and growth rates in solutions supersaturated with respect to C-S-H. Therefore, we used an experimental setup that leads to C-S-H precipitation and growth in solutions with a known KOH concentration. The results show that the KOH concentration in solution generally leads to an increase of the C-S-H growth rates at lower supersaturation levels. Based on these findings, we calculated theoretical reaction rates of C3S hydration using the precipitation rates of C-S-H. The comparison between these calculated rates and measured reaction rates from hydration experiments shows good agreement, allowing us to present a quantitative model for the effect of alkalis in combination with aluminum. Furthermore, we provide a quantitative analysis of how alkalis and aluminum modify reaction rates during the acceleration period of C3S hydration, which can be explained by different behaviors in the nucleation and growth of C-S-H.<br
Keywords: Hydration (A) Ca3SiO5 (D) Alkalis (D) Calcium-silicate-hydrate (B) Pore solution (B)

In Vitro performance assessment of new brushite-forming Zn- and ZnSr-substituted beta-TCP bone cements - Pina, Sandra; Vieira, Sandra; Torres, Paula M. C.; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; da Cruz e Silva, Odete A. B.; da Cruz e Silva, Edwyn F.; da Fonte Ferreira, José Maria (Journal of Biomedical Materials Research Part B-Applied Biomaterials, 2010)
The present study investigated the in vitro performance of brushite-forming Zn- and ZnSr-substituted β-TCP bone cements in terms of wet mechanical strength and biological response. Quantitative phase analysis and structural refinement of the powdered samples were performed by X-ray powder diffraction and Rietveld refinement technique. Initial and final setting times of the cement pastes, measured using Gilmore needles technique, showed that ZnSrCPC sets faster than ZnCPC. The measured values of the wet strength after 48 h of immersion in PBS solution at 37°C showed that ZnSrCPC cements are stronger than ZnCPC cements. Human osteosarcoma-derived MG63 cell line proved the nontoxicity of the cement powders, using the resazurin metabolic assay. © 2010 Wiley Periodicals, Inc.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LM.invitr
Keywords: Brushite cement; Cytotoxicity; Mechanical strength; Setting time

Iodp expedition 330: Drilling the louisville seamount trail in the SW Pacific - Koppers, Anthony A P; Yamazaki, Toshitsugu; Geldmacher, Jörg; Anderson, Louise; Buchs, David M.; Beier, Christoph; Chen, Li Hui; Cohen, Benjamin E.; Deschamps, Fabien; Dorais, Michael J.; Ebuna, Daniel; Ehmann, Sebastian; et al. (Scientific Drilling, 2013)
Deep-Earth convection can be understood by studying hotspot volcanoes that form where mantle plumes rise up and intersect the lithosphere, the Earth's rigid outer layer. Hotspots characteristically leave age-progressive trails of volcanoes and seamounts on top of oceanic lithosphere, which in turn allow us to decipher the motion of these plates relative to "fixed" deep-mantle plumes, and their (isotope) geochemistry provides insights into the long-term evolution of mantle source regions. However, it is strongly suggested that the Hawaiian mantle plume moved 15° south between 80 and 50 million years ago. This raises a fundamental question about other hotspot systems in the Pacific, whether or not their mantle plumes experienced a similar amount and direction of motion. Integrated Ocean Drilling Program (IODP) Expedition 330 to the Louisville Seamounts showed that the Louisville hotspot in the South Pacific behaved in a different manner, as its mantle plume remained more or less fixed around 48°S latitude during that same time period. Our findings demonstrate that the Pacific hotspots move independently and that their trajectories may be controlled by differences in subduction zone geometry. Additionally, shipboard geochemistry data shows that, in contrast to Hawaiian volcanoes, the construction of the Louisville Seamounts doesn't involve a shield-building phase dominated by tholeiitic lavas, and trace elements confirm the rather homogenous nature of the Louisville mantle source. Both observations set Louisville apart from the Hawaiian-Emperor seamount trail, whereby the latter has been erupting abundant tholeiites (characteristically up to 95% in volume) and which exhibit a large variability in (isotope) geochemistry and their mantle source components.

Ion-doped Brushite Cements for Bone Regeneration - Hurle, Katrin; Oliveira, J. M.; Reis, R. L.; Pina, S.; Götz-Neunhoeffer, Friedlinde (Acta Biomaterialia, 2021)
Decades of research in orthopaedics has culminated in the quest for formidable yet resorbable biomaterials using bioactive materials. Brushite cements most salient features embrace high biocompatibility, bioresorbability, osteoconductivity, self-setting characteristics, handling, and injectability properties. Such type of materials is also effectively applied as drug delivery systems. However, brushite cements possess limited mechanical strength and fast setting times. By means of incorporating bioactive ions, which are incredibly promising in directing cell fate when incorporated within biomaterials, it can yield biomaterials with superior mechanical properties. Therefore, it is a key to develop fine-tuned regenerative medicine therapeutics. A comprehensive overview of the current accomplishments of ion-doped brushite cements for bone tissue repair and regeneration is provided herein. The role of ionic substitution on the cements physicochemical properties, such as structural, setting time, hydration products, injectability, mechanical behaviour and ion release is discussed. Cell-material interactions, osteogenesis, angiogenesis, and antibacterial activity of the ion-doped cements, as well as its potential use as drug delivery carriers are also presented.
CRIS-Team Scopus Importer:2021-03-05
Keywords: Angiogenesis; Bone cements; Brushite; Drug delivery systems; Ionic dopants; Osseointegration; Tissue engineering; Tissue regeneration

Ionic Substitutions in biphasic Hydroxyapatite and ß-Tricalcium phosphate mixtures. Structural analysis by Rietveld Refinement - Kannan, Surekka; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; da Fonte Ferreira, José Maria (Journal of the American Ceramic Society, 2008)
The structural information on the influence of ionic additions in biphasic (hydroxyapatite (HAP) and beta-tricalciumphosphate (beta-TCP)) mixtures ranging from single ionic substitutions to combined ionic substitutions of most of the essential ions embedded in biological apatite was analyzed through the Rietveld refinement technique. The results have proved that the determined quantitative phase composition of HAP and beta-TCP in biphasic mixtures was dependent on the initial calcium (Ca) deficiency of the precursor powders precipitated from the different molar concentrations used in the synthesis. The substitution of cations (Na+, Mg2+, and K+) improved the stabilization of the beta-TCP structure whereas anions (F- and Cl-) were found incorporated at the OH- site of the HAP phase. Rietveld analysis of X-ray powder diffraction data from the present study proved to be a powerful technique to describe the position and occupancy of certain ions like Mg2+ and Cl- in the biphasic mixtures. However, it has also shown limitations in tracking back other ions like Na+, K+, and F-, which require the use of other complementary characterization methods.
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LM.ionics
Keywords: X-RAY-DIFFRACTION; CALCIUM-PHOSPHATE; THERMAL-STABILITY; CRYSTAL-STRUCTURE; HIGH-TEMPERATURE; SINTERING BEHAVIOR; DEFICIENT HYDROXYAPATITE; MECHANICAL PERFORMANCE; BONE METABOLISM; SOLID-SOLUTIONS

Iron isotope compositions of subduction-derived rocks: Insights from eclogites and metasediments of the Münchberg Massif (Germany) - Pohlner, Johannes E.; El Korh, Afifé; Chiaradia, Massimo; Klemd, Reiner; Grobéty, Bernard; Pettke, Thomas (Chemical Geology, 2022)
The Fe isotope systematics of subducted lithologies are crucial for the understanding of redox-dependent mass transfer in subducting slabs, with consequences for the compositions of arc magmas and of the deep mantle. We investigated eclogites, metagabbros, and paragneisses from the Variscan Münchberg Massif to unravel whether their Fe isotope compositions are dominated by the igneous/sedimentary protolith signature, by low-temperature seawater alteration, or by later fluid-rock interactions during the subduction-exhumation cycle. Although the eclogites are thought to be derived from a continental rather than oceanic setting (possibly a rift-drift transition stage), they have mid-ocean ridge basalt (MORB)-like major and trace element compositions. They are often moderately oxidized compared to MORB (Fe3+/ΣFe = 0.06 to 0.30). Their δ56Fe values (+0.00 to +0.17‰; mean + 0.08 ± 0.01‰) mostly resemble those of MORB (+0.07 to +0.17‰). The metagabbros, which are derived from a more enriched mantle source than the eclogites, yielded heavier δ56Fe values (+0.09 to +0.22‰) similar to ocean island basalts, whereas those of the paragneisses (+0.03 to +0.10‰) are typical for pelitic sediments. It appears that the Fe isotope compositions of the igneous protoliths are largely preserved and little if any Fe was mobilized during the diverse fluid-rock interaction stages. The parental magma of the eclogites was probably somewhat isotopically lighter than similarly differentiated MORB magmas, perhaps due to the presence of metasomatized, isotopically light peridotites in the subcontinental lithospheric mantle (SCLM) source. Although it is possible that δ56Fe values were slightly modified during seawater alteration and/or metamorphic fluid-rock interactions in some of the eclogites, the impact of fluid-rock interactions on the major element compositions of the eclogites appears to be small. Furthermore, the scarcity of metamorphic veins in the Münchberg Massif argues against significant Fe mobilization in the slab. We suggest that continental eclogites tend to retain their magmatic δ56Fe values throughout the subduction-exhumation cycle, whereas δ56Fe values of oceanic eclogites may often be dominated by seafloor alteration with potential local modifications in the slab close to fluid channels. The remarkable robustness of the Fe isotope compositions of continental eclogites suggests that they may be used to reconstruct protolith mantle source properties despite the complex post-magmatic history.
CRIS-Team Scopus Importer:2022-05-20
Keywords: Eclogites; Fe isotopes; Fluid-rock interactions; Subduction

Iron isotope evidence in ocean island basalts for plume- and plate-controlled melting, São Miguel, Azores - Ruttor, Saskia; Nebel, Oliver; Williams, Helen; Beier, Christoph; Richter, Marianne; Nebel-Jacobsen, Yona; Romer, René; Turner, Simon P.; Soderman, Caroline R. (Geochimica Et Cosmochimica Acta, 2022)
Primitive ocean island basalts (OIB) display a large variability in stable iron (Fe) isotopes, beyond what can plausibly be explained by partial melting and crystal fractionation processes. This Fe isotopic heterogeneity is widely ascribed to inheritance from various exotic mantle components of enriched crustal origin, i.e., subducted and resurfacing oceanic or continental crust, its underlying lithosphere or overlying sediments. These enriched mantle components are characterised by variations in radiogenic Sr-Nd-Pb-Hf isotopes. The extent to which the inherited Fe isotopic signature of subducted and recycled material influences the Fe isotopic composition of OIB and which role secondary processes accompanied with partial melting play is, however, not well understood. The eastern Azores island of São Miguel displays a systematic change from a mantle source less radiogenic in Sr-Nd-Hf-Pb isotopes in the West to a highly enriched source in the East. These variations are among the largest reported in an OIB, indicating variable source component additions to the melt that offer a natural laboratory to elucidate sub-oceanic island processes. Among these, the eastern São Miguel component is unique amongst global OIB in that it has both, extremely radiogenic 206Pb/204Pb and 87Sr/86Sr isotopic ratios. The spatial distribution, complexity and uniqueness of these isotopic source characteristics are ideally suited to gain insights into the spatial distribution of mantle components and their potential controls on Fe isotope systematics. Comparing δ57Feprim, which is the isotopic composition calculated to primitive lavas along a liquid line of descent, with 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and 208Pb/204Pb reveals that the depleted component of western São Miguel shows a heavy Fe isotopic composition ranging from δ57Feprim = +0.09 to +0.18‰ (excluding one outlier at −0.02‰ δ57Feprim), whereas the enriched component of eastern São Miguel shows lighter δ57Feprim = +0.05 to +0.12‰. Both suites show a continuum of isotopic compositions between two apparent endmembers. The light Fe isotopic signature of eastern São Miguel lavas, coupled with elevated Rb/Sr and K2O, indicate K-rich mantle metasomatism in their source. The Fe isotopic composition of western São Miguel's lavas are likely related to a similar source, but have been overprinted by the active Terceira Rift. The latter adds low-degree mid-ocean ridge basalt (MORB)-type melts to the original OIB, likely in the form of a re-fertilised depleted mantle component that underpins the ultraslow spreading region. The two-component mix that contributes to western São Miguel lavas highlights that both enriched mantle components and shallow crustal features can add to the Fe isotopic signatures of erupting OIB, with spatial separation within single volcanic islands. This suggests that a careful evaluation of local geologic features, such as rifting, is required when OIB are probed for their mantle sources, and that heavy Fe isotopic signatures in OIB may not reflect deep, plume-source lithologies. In summary, São Miguel lavas are sourced by a mantle plume, but within a spatially controlled region accompanied by a plate-controlled melt associated with a rifting zone. This dichotomy adds another complication to the genesis of OIB, which however maybe elucidated through combined radiogenic-stable isotope systematics.
CRIS-Team Scopus Importer:2022-09-16
Keywords: Azores; Fe isotopes; Melting; Metasomatism; Peridotite; Rift

Isobaric cooling and anti-clockwise P-T paths in the Variscan Odenwald Crystalline Complex, Germany - Schmädicke, Esther; et al. (Journal of Metamorphic Geology, 2003)
Keywords: KFMASH pseudosections; Anti-clockwise P-T paths; Mid-German Crystalline Rise; Low-P/high-T metamorphism; Variscides

Isolated alkaline basalt occurrences in the northern Spessart, Germany: Outposts of the Early Miocene Vogelsberg shield volcano? - Okrusch, Martin; Schuessler, Ulrich; Van Den Bogaard, Paul; Koglin, Nikola; Brätz, Helene; Lorenz, Joachim; Karbusicka, Cliff; Spiegl, Tobias (Neues Jahrbuch für Mineralogie-Abhandlungen, 2020)
Four isolated occurrences of Tertiary volcanic rocks in the northern Spessart at Beilstein, Hoher Berg, Madstein and Kasselgrund are relics of volcanic vents or dikes. They display alkaline basalts (s.l.) with mainly trachybasaltic composition, which, from nonnative mineral contents, may be designated as nepheline-bearing alkali-olivine basalts and basanites. In part, centimetre-sized xenoliths of spinel lherzolite occur. According to Ar-Ar dating, the alkaline basalts (s.l.) from Kasselgrund have erupted at 18.1 +/- 0.3 or 19.3 +/- 0.4 Ma, those of Hoher Berg between c. 18 and c. 21 Ma. These ages correspond to the Vogelsberg eruption stage I.A slightly younger Ar-Ar age of 16.8 +/- 0.3 Ma was recorded for the Beilstein basalt, which is in chronological accordance to the turn of Vogelsberg eruption stages II and III. Samples of all four occurrences reveal major and trace element compositions, which are different from those of the Vogelsberg basalts. Compositions of basalts of the stage III from Vogelsberg coincide most with the Spessart basalts. This signals a special position of the northern Spessart volcanic rocks either as a discrete spatial part of the Vogelsberg volcanic suite or as smaller, independent eruption centres.
CRIS-Team WoS Importer:2020-08-07

Isotope alteration caused by changes in biochemical composition of sedimentary organic matter - Liu, Xiaoqing; Hilfert, Liane; Barth, Johannes; van Geldern, Robert; Friese, Kurt (Biogeochemistry, 2020)
Stable carbon (C) and nitrogen (N) isotope ratios of sedimentary organic matter (OM) can reflect the biogeochemical history of aquatic ecosystems. However, diagenetic processes in sediments may alter isotope records of OM via microbial activity and preferential degradation of isotopically distinct organic components. This study investigated the isotope alteration caused by preferential degradation in surface sediments sampled from a eutrophic reservoir in Germany. Sediments were treated sequentially with hot water extraction, hydrochloric acid hydrolysis, hydrogen peroxide oxidation and di-sodium peroxodisulfate oxidation to chemically simulate preferential degradation pathways of sedimentary OM. Residue and extracts from each extraction step were analyzed using elemental analyzer-isotope ratio mass spectrometry and solid-state 13C nuclear magnetic resonance spectroscopy. Our results show that stable C and N isotope ratios reacted differently to changes in the biochemical composition of sedimentary OM. Preferential degradation of proteins and carbohydrates resulted in a 1.2‰ depletion of 13C, while the isotope composition of 15N remained nearly the same. Sedimentary δ15N values were notably altered when lignins and lipids were oxidized from residual sediments. Throughout the sequential fractionation procedure, δ13C was linearly correlated with the C:N of residual sediments. This finding demonstrates that changes in biochemical composition caused by preferential degradation altered δ13C values of sedimentary OM, while this trend was not observed for δ15N values. Our study identifies the influence of preferential degradation on stable C isotope ratios and provide additional insight into the isotope alteration caused by post-depositional processes.
CRIS-Team Scopus Importer:2020-02-14
Keywords: Biochemical composition; Organic matter; Preferential degradation; Sediment; Stable carbon and nitrogen isotope ratios

Isotopic and kinetic constraints on methane origins in Icelandic hydrothermal fluids - Stefánsson, Andri; Ricci, Andrea; Garnett, Mark; Gunnarsson-Robin, Jóhann; Kleine-Marshall, Barbara; Scott, Samuel W.; Lelli, Matteo; Cardoso, Carolina Dantas; Pik, Raphaël; Santinelli, Chiara; Ono, Shuhei; Barry, Peter H.; et al. (Geochimica Et Cosmochimica Acta, 2024)
The origin of methane in hydrothermal fluids has long been a subject of debate – whether it is abiotic or biotic. In this study, we aim to unravel and quantify the sources of CH4 in active hydrothermal systems by adopting a holistic approach analyzing well characterized high-temperature hydrothermal fluids (∼230–310 °C) in Iceland. We employ a broad variety of geochemical and isotope indicators, encompassing chemical and isotope compositions of the targeted fluids. These signatures are then compared with results from chemical and isotope kinetic models and data from sedimentary-hosted hydrothermal systems. Carbon species in these fluids include CO2 (2.60–184 mmol/kg), CH4 (2.39·10−4–0.325 mmol/kg), dissolved organic carbon (4.78·10−3–0.112 mmol/kg), and CO (1.89·10−6–4.16·10−4 mmol/kg). Carbon and helium isotopes suggest a relatively uniform mantle-derived source of CO2 (δ13C-CO2: −4.80 to −1.50 ‰, CO2/3He: 1.49·109–4.14·1010 14C-CO2: 0.11–2.42 pMC). Methane, in contrast, has multiple sources. Overall, chemical equilibria among carbon species (CO2, CH4, CO) is not attained, suggesting kinetic controls. Tritium content (<0.8–1.42 TU) and hydrologic constraints indicate relatively short hydrothermal fluid residence times (∼5–200 years), with occasional inputs from older water components. Within this short timeframe, CH4 concentrations vary from lower, to significantly higher than those calculated using CO2 reduction kinetics. The isotope composition (δD-CH4: −172 to −138 ‰, δ13C-CH4: −32.0 to −24.6 ‰; 14C-CH4: 0.36–11.54 pMC) and geochemical and isotope modeling suggest that the majority (>80–90 %) of CH4 originates from a radiocarbon inactive source, i.e. mantle CH4, reduction of mantle CO2 and/or old organic matter, with relatively small contributions from both marine (<20 %) and terrestrial (<10 %) dissolved organic carbon. Measured isotopic compositions of CH4 do not match those expected for mantle-derived CH4 as well as values generated from reduction of mantle-derived CO2. Instead, differences in δD-CH4 and δ13C-CH4 values exist between systems fed by meteoric water and those fed by seawater, challenging the assumption of a uniform CO2 source and invariable reaction mechanisms. Differences between systems are best explained by variable extent of thermal decomposition and primary variations in the isotope composition of marine and terrestrial organic matter. Also, δD-CH4 and δ13C-CH4 values in meteoric water-fed systems closely resemble those in the Öxarfjördur sedimentary-hosted systems. In summary, our data supports a predominant thermogenic origin of CH4 in both seawater and terrestrial hydrothermal fluids in Iceland. The source of organic matter appears to be a combination of modern dissolved organic carbon and older sedimentary deposits. In addition, some of the hydrothermal systems studied (Krafla, Reykjanes, Theistareykir) which are characterized by low CH4 concentrations, may contain a significant portion of CH4 that may originate from CO2 reduction.
CRIS-Team Scopus Importer:2024-04-12
Keywords: Hydrothermal fluids; Isotopes; Kinetic modeling; Methane origin

Isotopic and trace element geochemistry of the Seligdar magnesiocarbonatites (South Yakutia, Russia): Insights regarding the mantle evolution beneath the Aldan-Stanovoy shield - Doroshkevich, Anna G.; Prokopyev, Ilya R.; Izokh, Andrey E.; Klemd, Reiner; Ponomarchuk, Anton V.; Nikolaeva, Irina V.; Vladykin, Nikolay V. (Journal of Asian Earth Sciences, 2018)
The Paleoproterozoic Seligdar magnesiocarbonatite intrusion of the Aldan-Stanovoy shield in Russia underwent extensive postmagmatic hydrothermal alteration and metamorphic events. This study comprises new isotopic (Sr, Nd, C and O) data, whole-rock major and trace element compositions and trace element characteristics of the major minerals to gain a better understanding of the source and the formation process of the carbonatites. The Seligdar carbonatites have high concentrations of P2O5 (up to 18 wt%) and low concentrations of Na, K, Sr and Ba. The chondrite-normalized REE patterns of these carbonatites display significant enrichments of LREE relative to HREE with an average La/Ybcn ratio of 95. Hydrothermal and metamorphic overprints changed the trace element characteristics of the carbonatites and their minerals. These alteration processes were responsible for Sr loss and the shifting of the Sr isotopic compositions towards more radiogenic values. The altered carbonatites are further characterized by distinct 18O- and 13C-enrichments compared to the primary igneous carbonatites. The alteration most likely resulted from both the percolation of crustal-derived hydrothermal fluids and subsequent metamorphic processes accompanied by interaction with limestone-derived CO2. The narrow range of negative εNd(T) values indicates that the Seligdar carbonatites are dominated by a homogenous enriched mantle source component that was separated from the depleted mantle during the Archean.<br
Keywords: Magnesiocarbonatites; Trace element composition and isotopic data; Hydrothermal processes; Enriched source; Aldan-Stanovoy shield

Isotopic composition of inorganic carbon as an indicator of benzoate degradation by Pseudomonas putida: Temperature, growth rate and ph effects - Barth, Johannes; et al. (Rapid Communications in Mass Spectrometry, 2000)

Isotopic niches of sympatric Gentoo and Chinstrap Penguins: evidence of competition for Antarctic krill? - Dimitrijevic, Danijela; Paiva, Vitor H.; Ramos, Jaime A.; Seco, José; Ceia, Felipe R.; Chipev, Nesho; Valente, Tiago; Barbosa, Andrés; Xavier, José C. (Polar Biology, 2018)
As climate change, among other factors, is increasingly affecting Antarctic marine systems, competition for price may increase between predators, particularly in the Antarctic Peninsula which has warmed more than elsewhere. Under such a context, we tested the feeding and trophic ecology of Gentoo ( Pygoscelis papua ) and Chinstrap ( Pygoscelis antarctica ) penguins breeding in sympatry at Livingston Island (Antarctic Peninsula) in a single season. We compared the diets of adults (from faecal samples, and stable isotopes in feathers and blood) and chicks (from stomach contents, and stable isotopes in down feathers, toenails and muscles of chicks that had died of unknown causes). Antarctic krill Euphausia superba dominated the diet of both species, although Gentoo Penguins fed on larger Antarctic krill than did Chinstrap Penguins. Stable isotope analyzes of adult tissues revealed that both species fed at different niches in successive years, as depicted by the different levels δ 13C in feathers (showing values ​​from the previous breeding season) and whole blood (showing values ​​from the current season). Tissues collected from chicks confirmed their diet over different time scales (ie days to weeks): Gentoo Penguins fed at a higher trophic level (possibly due to a more varied diet) and in different habitats than Chinstrap Penguins, providing evidence of isotopic niche separation of penguins. Our results may be relevant to the monitoring programs of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) and suggest that adult scats, and stomach contents and tissues of recently died chicks, can be used in such programs.<br

Isotopic seawater temperatures in the Albian Gault Clay of the Boulonnais (Paris Basin): palaeoenvironmental implications - Bomou, Brahimsamba; Deconinck, Jean-Francois; Puceat, Emmanuelle; Amedro, Francis; Joachimski, Michael; Quillevere, Frederic (Proceedings of the Geologists Association, 2016)
Keywords: Albian; Belemnites guards; Fish teeth; Foraminifera; Gault Clay Formation; Oxygen isotopes; Palaeotemperature; Paris Basin; Selachian teeth

ITER Project: How physical-thermal properties of soils affect the heat transfer in very shallow geothermal application - Di Sipio, Eloisa; Bertermann, David (Abstract Volume 9. Marktredwitzer Bodenschutztage Bodenschutz beim Planen und Bauen, 2016)
In the near future the shallow geothermal energy resource is becoming increasingly important as renewable energy resource for heating/cooling residential and tertiary buildings. Therefore, it is worthy of interest to get a better comprehension of how the different soil typologies (i.e. sand, loamy sand...) affect and are affected by the heat transfer exchange with heat collectors, especially when horizontal ones (very shallow geothermal installations) are adopted
Keywords: very shallow geothermal systems; thermal conductivity; horizontal collectors; soil properties