Polyphase growth history of peritectic garnet from a granite: Trace-element zonation, Lu-Hf ages and their significance for the duration of granite-forming processes - Jung, S.; Pfänder, J. A.; Mezger, K.; Hellebrand, E.; Brandt, Sönke (Lithos, 2022)
Determining the ages and duration of high-grade metamorphic episodes during orogenesis and concomitant melt extraction events is pivotal in reconstructing and quantifying the chemical and petrological evolution of the Earth's continental crust over time. Major and trace elements combined with multichronometric garnet data from the Pan-African Damara belt of Namibia place absolute time constraints on high-grade regional metamorphism and melting in the lower crust that led to the production of widespread granites emplaced in the upper crust. Some of these granites contain inherited peritectic garnet with inferred igneous rims that record their genesis and evolution from formation by partially melting in the deep crust to the emplacement of their host rock at shallower levels. Particular characteristics of these garnets are textural and chemical disequilibrium features such as resorption, local development of partly euhedral crystal faces and occurrence of quartz-feldspar stringers in the rim of the garnet and trace element abundances with sharp concentration gradients. These features document a previous melting event followed by garnet crystallization in an ascending melt. With the exception of the outermost rim, which records late-stage diffusional features, the garnet crystals have constant Mg and Mn concentrations. In contrast, Ca shows pronounced chemical zoning. Trace elements (HREE, LREE, Zr, Sr, Y) are depleted in the core and enriched in the rim region indicating disequilibrium conditions during garnet growth. A pseudosection calculated with the garnet rim composition and the composition of the host granite yields P-T conditions of 0.62 GPa and 760 °C for the formation of the rim. This result is consistent with a P-T estimate of 0.68 GPa and 760 °C derived from the conventional garnet-biotite thermobarometer. Regional metamorphic conditions were above the cordierite-andalusite stability field with estimated conditions of 550-600 °C and 0.4–0.5 GPa. This P-T regime indicates that the garnet originally crystallized at deep crustal levels. Diffusion modelling suggests that the observed concentration gradient of Sm in garnet is consistent with a maximum duration of ca. 0.5–1.5 Ma for the inferred melting interval during peak metamorphism in the lower crust. High-precision multi-point Lu-Hf garnet-whole rock data yield dates of 522.0 ± 1.0 and 522.3 ± 0.9 Ma for two samples. Because of presumed short intervals between melting in the lower crust and intrusion of the granite, these dates are interpreted as the age of the melting event during high-grade metamorphism and are temporally indistinguishable from the crystallization interval. Thus, dehydration melting in the deeper crust during peak metamorphism produced peritectic garnet that was incorporated into the granitic melt followed by subsequent new growth of igneous garnet around peritectic cores during intrusion. Previously obtained Sm-Nd garnet whole rock ages are 20–25 Ma younger and likely represent cooling ages. This study shows that granites enriched in mafic components such as garnet and biotite may intrude as mixtures of melt and the peritectic assemblage produced by incongruent melting involving dehydration-melting of biotite in the lower crust. Melting episodes represent short-lived processes relative to the absolute duration of orogenic cycles.
CRIS-Team Scopus Importer:2022-04-15
Keywords: Damara orogen; Lu-Hf garnet dating; Peritectic garnet; Pseudosection modelling; Trace element garnet

Pore‑fluid‑dependent controls of matrix and bulk thermal conductivity of mineralogically heterogeneous sandstones - Kämmlein, Marion; Stollhofen, Harald (Geothermal Energy, 2019)
For a variety of geothermal engineering applications, the only indirectly determinable matrix thermal conductivity (λm) is frequently used to convert the measured bulk rock thermal conductivity (λb) of air-saturated sandstones to water-saturated conditions. However, the necessary assumption that the absolute value of λm remains constant irrespective of the pore fluid present turns out to be not valid in practice and the explicit control factors on λm have not been demonstrated yet for different pore fluids. A pore fluid-controlled change in the λm value also questions the transferability of empirical proxy models for the estimation of water-saturated λb when they were calibrated on air-saturated samples. This study applies a multiple regression analysis to quantitative mineralogical composition data and porosity (Φ) to identify the controls of the λm for different types of pore fluids (water- vs. air-saturation). In addition, the differences in the calculated λm values resulting from different calculation methods or input data (theoretical geometric mean model or mineralogical composition data) are examined. We further test the suitability of different sandstone properties as potential proxies for the estimation of the λb, with respect to the pore fluid type. Differences in the absolute value of λm of sandstones from different measurement conditions (air- or water-saturated) are most probably related to the formation of authigenic kaolinite in the pore space, originating from the alteration of alkali feldspar. In addition, the thermal properties of the rock matrix are mainly controlled by the volume fractions of the high thermally conductive mineral fractions quartz and dolomite. Empirical models that have solely Φ or P-wave velocity (vp) as variables are not suitable for the prediction of water-saturated λb of sandstones. Instead, quantitative mineralogical data of high thermally conductive mineral phases such as quartz and dolomite have to be included. The easily measureable vp is proposed as a promising proxy for both pore fluid types tested: combined with the total quartz volume/porosity ratio for air-saturated sandstones, and combined with the quartz plus dolomite volume fractions for water-saturated sandstones.<br
Keywords: Matrix thermal conductivity; Bulk thermal conductivity; Pore fluid; Sandstone; Mineralogical composition; Anisotropy

Porenüberdruck im Bayerischen Molassebecken - Drews, Michael; Bauer, Wolfgang; Stollhofen, Harald (Erdoel Erdgas Kohle/EKEP, 2018)

Porenüberdruck im Bayerischen Molassebecken - Drews, Michael; Bauer, Wolfgang; Stollhofen, Harald (DGMK Tagungsbericht 2018-April, 2018)

Pore structure of hardened cement paste containing colloidal polymers with varied glass transition temperature and surface charges - Zhang, Chaoyang; Kong, Xiangming; Lu, Zichen; Jansen, Daniel; Pakusch, Joachim; Wang, Shengxian (Cement & Concrete Composites, 2019)
Influences of four polymer latexes with varied glass-transition-temperature (Tg) and colloidal surface properties on pore structure of hardened cement pastes (hcps) were investigated by means of mercury intrusion porosimetry (MIP), nitrogen adsorption measurement (NAM) and SEM. MIP measurement indicates that polymer addition leads to increase of total pore volume and threshold pore size, whereas NAM shows that pore volume in the range of 2–100 nm decreases with addition of polymers, implying a sealing effect. The conflicting results between MIP and NAM originate from destruction and movement of the polymer phase by high pressure mercury intrusion during MIP measurement. SEM reveals that low-Tg polymers form continuous film while high-Tg polymers remain particle form in hcps. The film-forming polymers provide stronger sealing effect than the non-film-forming polymers. Moreover, the non-adsorbing polymers exhibit stronger sealing effect than the adsorbing polymers due to their preferential locations in aqueous phase of fresh cement paste.
CRIS-Team Scopus Importer:2019-10-08
Keywords: Hardened cement paste (hcp); Polymer latex; Pore structure; Sealing effect

Porphyry and epithermal deposits in Greece: An overview, new discoveries, and mineralogical constraints on their genesis - Voudouris, P.; Mavrogonatos, C.; Spry, P. G.; Baker, T.; Melfos, V.; Klemd, Reiner; Haase, Karsten; Repstock, A.; Djiba, A.; Bismayer, U.; Tarantola, A.; Scheffer, C.; et al. (Ore Geology Reviews, 2019)
Greece hosts a variety of magmatic-hydrothermal ore deposits/prospects with porphyry- and epithermal styles playing a major role in its total gold endowment. These deposit types are mainly clustered in two areas, the Rhodope- and Attico-Cycladic massifs, and formed from about 33 Ma to the Pleistocene, as a result of back-arc extension in the Aegean Sea, metamorphic core complex formation, and contemporaneous post-subduction and arc magmatism. In the Serbo-Macedonian massif, porphyry Cu-Au deposits include Skouries, Fisoka, Tsikara, Vathi and Gerakario. Causative intrusives are Oligocene to Miocene granodiorites to monzonites. Gold and PGE mineralization is associated with potassic alteration of the intrusives. In the eastern Rhodope massif and the NE Aegean islands, porphyry prospects occur at Pagoni Rachi, Konos Hill, Myli, Melitena (west Thrace), Fakos, Sardes, and Kaspakas (Limnos island) and Stypsi (Lesvos island). Mineralization is associated with Oligocene to Miocene subvolcanics of calc-alkaline to shoshonitic affinity. Feature of these prospects, which they share in common with several porphyry Au-only systems, is their shallow depth of emplacement, the presence of potassic/sodic-calcic and/or phyllic alteration, a strong epithermal overprint, their low Cu content, an extreme Re-enrichment, the multistage introduction of Au, the presence of banded quartz veinlets, and the local presence of tourmaline. New discoveries of porphyry-style mineralization at King Arthur, St. Philippos and Aisymi, increases the gold potential in west Thrace. High-intermediate sulfidation epithermal Au-Ag polymetallic deposits/prospects overprint and/or occur laterally from porphyry-style mineralization, where they are spatially associated with lithocaps of advanced argillic alteration. High-intermediate sulfidation Au-Ag epithermal mineralization at Perama Hill, Mavrokoryfi and Pefka in west Thrace, and at Pterounda, Mesotopos and Megala Therma on Lesvos island is controlled by steeply-dipping extensional faults within volcanic rocks, without any obvious genetic relationship to spatially-related porphyry-style mineralization. Polymetallic epithermal deposits and prospects contain critical and energy critical metals (e.g., Te, Se, Bi, Sb, In, Ge and Ga), which may be considered as by-products. In the Attico-Cycladic area, porphyry Mo-W mineralization occurs as sheeted quartz veins and stockworks cutting a potassic- to sericitic-altered Miocene granodiorite stock in the Lavrion district. Bonanza grade Au- and/or Ag-rich veins with epithermal affinities crosscut metamorphic rocks at Lavrion, and on Syros, Tinos, Antiparos and Anafi islands. Milos island is characterized by shallow submarine volcanic-hosted IS-HS epithermal Au-Ag-Te and base metal deposits. Antimony-As-Ag-Au deposits/prospects on Chios, Samos and Kos islands in the eastern Aegean Sea, indicate the potential for Carlin-style mineralization in Greece. Several factors played a role to the metal endowment of the Aegean porphyry-epithermal systems: magma fertility in the source regions, depth of emplacement of causative intrusives, relative contribution of mantle versus crustal material, redox state of subduction-related magmas, and physico-chemical fluid conditions at the site of ore deposition.
CRIS-Team Scopus Importer:2019-05-09
Keywords: Alteration; Epithermal; Greece; Ore mineralogy; Porphyry

Positive sport-biosphere interactions? − Cross-country skiing delays spring phenology of meadow vegetation - Steinbauer, Manuel; Kreyling, Jürgen; Stöhr, Caroline; Audorff, Volker (Basic and Applied Ecology, 2018)
Space requirements by winter sports and accelerating global warming are usually perceived as stressors for mountain meadow plant communities. Cross-country ski track preparation (i.e. grooming), however, might retard effects of climate change and, being limited in space requirements, might increase abiotic heterogeneity. The effect of cross-country ski tracks on meadow vegetation was quantified along a representative ski track that had been operated for 30 years in the Fichtelgebirge, a low mountain range in central Europe. Paired sampling was implemented to assess the effect of skiing operations on snow and soil properties, plant phenology, biomass production and species composition. Additionally, boosted regression tree analyses were used to quantify the relative importance of the cross-country ski track compared to other environmental conditions. The cross-country ski track strongly increased snow density, enhanced soil frost, and retarded snowmelt, thereby delaying flower phenology (by 2.1 days) and the early development stages of plant species on the track. However, biomass, species richness and species composition were unaffected by skiing operations except for one species (Leontodon autumnalis) showing exclusive occurrence on the track while four others showed reduced relative occurrence on the track. While snow and soil properties were influenced by cross-country ski track preparation, natural environmental variability was more influential for species composition and biomass production than the ski track. We therefore conclude that the ski track – without artificial snow – did not negatively affect species composition. By delaying flower phenology, effects of the ski track even counteracted global warming to some degree. Due to their small spatial extent in the landscape, these ski tracks may add to environmental heterogeneity and thus support sustaining diverse species compositions during environmental changes.

Possible links between groundwater geochemistry and chronic kidney disease of unknown etiology (CKDu): an investigation from the Ginnoruwa region in Sri Lanka - Balasooriya, Shyamalie; Munasinghe, Harshaka; Herath, A. T.; Diyabalanage, Saranga; Ileperuma, O. A.; Manthrithilake, Herath; Daniel, Christoph; Amann, Kerstin Ute; Zwiener, Christian; Barth, Johannes; Chandrajith, Rohana (Exposure and Health, 2019)
Since at least two decades, Chronic Kidney Disease of Uncertain Etiology (CKDu) has become an increasingly discussed health issue in Sri Lanka and as well as in other tropical regions. Areas that are particularly affected with the disease are mostly located in the dry zone of Sri Lanka. The disease is more prominent among communities that consume groundwater as their main source of drinking water. Hydrogeochemical investigations were carried out in the Ginnoruwa area, a known hotspot of CKDu. It revealed possible links between drinking water chemistry and the spreading of the disease. This work compares hydrogeochemical data of drinking water sources of wells whose consumers are affected by CKDu and other nearby wells whose consumers were not affected by the disease. A total of 63 groundwater samples were collected from selected wells. About one-third of these samples (i.e., 19) were collected from wells used by CKDu patients. Significantly higher values of pH, total hardness, electrical conductivity, Ca2+, Mg2+, F−, Cl−, PO4 3−, and SO4 2− were found in wells that were used by CKDu patients. Mean contents of Na+, Ca2+, and Mg2+ in CKDu affected wells were 33.8 mg/L, 30.1 mg/L, and 14.9 mg/L, respectively, compared to 23.1 mg/L, 26.7 mg/L, and 9.65 mg/L in non-CKDu wells. Differences in major ion geochemistry in groundwaters are possibly governed by variable time periods of water storage in fractured hard rock aquifers in this region. Hydrogeochemical parameters were statistically compared by a Mann–Whitney U test and indicated significant differences in total dissolved solids (TDS) (p = 0.016), SO4 2− (p = 0.005), PO4 3− (p = 0.030), F− (p = 0.048), Na+ (p = 0.008), and Mg2+(p = 0.008) between non-CKDu and CKDu wells at p = 0.050 level. Other suspected solutes such as nephrotoxic trace elements including As, Cd, and Pb were similar in both types of wells. They were also lower than the accepted guideline limits of the World Health Organization (WHO). Results of this study suggest that fluoride in drinking water in combination with water hardness may be one of the responsible factors for kidney damage and progression of the disease. This may be particularly the case when elevated amounts of Mg2+ are present in hard groundwater.
CRIS-Team Scopus Importer:2019-12-31
Keywords: Fluoride; Girandurukotte; Kidney damage; Magnesium; Mann–Whitney U test; Water hardness

Possible oceanic circulation patterns, surface water currents and upwelling zones in the Early Palaeozoic - Servais, Thomas; Danelian, Taniel; Harper, David A.T.; Munnecke, Axel (GFF, 2014)
As global reconstructions for the Early Palaeozoic (Cambrian, Ordovician and Silurian periods) are now becoming more reliable, ancient atmospheric and oceanic circulation patterns may now be modelled with increasing confidence. Here we examine previous studies on Early Palaeozoic palaeoceanography. It is assumed that past circulation patterns were governed by the same factors that govern them today. We here introduce some hypothetical base maps that predict the possible locations of ancient surface water currents, the position of oceanic gyres and possible ancient upwelling zones. © 2014 © 2014 Taylor & Franci
Keywords: Early Palaeozoic; palaeoceanography; palaeogeography; upwelling zones

Post-collisional shortening in the late Pan-African Hamisana high strain zone, SE Egypt: Field and magnetic fabric evidence - de Wall, Helga; et al. (Precambrian Research, 2001)
Keywords: Arabian-Nubian shield; Hamisana zone; Late-orogenic compression; Magnetic susceptibility

Post-Columbian environmental history of Lago Petén Itzá, Guatemala - Pérez, Liseth; Bugja, Rita; Massaferro, Julieta; Steeb, Philip; van Geldern, Robert; Frenzel, Peter; Brenner, Mark; Scharf, Burkhard; Schwalb, Antje (Revista Mexicana De Ciencias Geologicas, 2010)
Keywords: Chironomids; Eutrophication; Freshwater ostracodes; Geochemistry; Guatemala; Lago Petén Itzá; Lake level

Post-depositional alteration of stable isotope signals by preferential degradation of algae-derived organic matter in reservoir sediments - Liu, Xiaoqing; Wendt-Potthoff, Katrin; Barth, Johannes; Friese, Kurt (Biogeochemistry, 2022)
Post-depositional degradation of organic matter (OM) in freshwater sediments is crucial for driving the biogeochemical dynamics and influencing the carbon burial. This process also often causes diagenetic alteration on paleoenvironmental proxies. Yet, mechanisms behind degradation of sedimentary OM and depth-related variations in stable isotope ratios can so far only be explained in part. Degradation of sedimentary OM in two drinking water reservoirs with contrasting eutrophic and mesotrophic states and different catchment land use (agriculture versus forestry) was studied. A 4-step procedure was used to chemically separate sedimentary OM in terms of biochemical composition. Here we presented depth profiles of biochemical composition of sedimentary OM that helped to quantify preferential degradation of aquatic proteins and carbohydrates and the following removal of aquatic lipids. Sediment in the eutrophic reservoir, which reflected a larger contribution of algal-derived OM than the mesotrophic reservoir with a forest dominated catchment, was therefore subject to more intensive degradation of sedimentary OM along with delta C-13 and delta N-15 alterations. In addition, changes in the relative proportions of biochemical components in sedimentary OM had more pronounced impact on delta N-15 values relative to delta C-13. Our findings suggest that the lability of algae-derived OM leads to uncertainties for the estimation of carbon burial in water bodies and obscures paleo-limnological information derived from isotopic proxies. Post-depositional modifications are more pronounced in eutrophic freshwaters that accumulated more readily degradable OM of algal origin in their sediments. Recognition of these modifications will help constrain carbon burial rates of productive lakes and reservoirs and assess the role of reservoirs in carbon cycling.
CRIS-Team WoS Importer:2022-05-27

Post-depositional REE mobility in a Paleoarchean banded iron formation revealed by La-Ce geochronology: A cautionary tale for signals of ancient oxygenation - Bonnand, P.; Lalonde, S. V.; Boyet, M.; Heubeck, C.; Homann, M.; Nonnotte, P.; Foster, I.; Konhauser, K. O.; Köhler, Inga (Earth and Planetary Science Letters, 2020)
Precambrian banded iron formations (BIF) are chemical sedimentary deposits whose trace element signatures have been widely used to interrogate the chemical composition and redox state of ancient seawater. Here we investigated trace element signatures in BIF of the 3.22 Ga Moodies Group, Barberton Greenstone Belt (South Africa), which are interbedded with near-shore siliciclastic sedimentary rocks and represent one of the oldest known shallow-water occurrences of BIF. Unusual rare earth element (REE) signatures, notably with pronounced negative Ce anomalies in shale-normalized spectra, have been previously reported for chemical sediments of the Moodies Group, which we confirm here through an expanded dataset for Moodies BIF spanning three different localities. We find negative Ce anomalies as low as 0.2 Ce/Ce⁎ that are associated with unusual enrichment of LREE relative to HREE in the sample set. While total REE abundances and certain REE features appear strongly related to the concentration of detrital indicators (e.g., Zr), and are likely primary, other features, notably LREE enrichment, cannot be explained as a primary feature of the sediment. This is better explained by later addition of REE from a LREE-enriched but Ce-depleted fluid that generated the significant negative Ce anomalies observed in surface samples of Moodies Group BIF. This REE addition event influenced both Sm-Nd and La-Ce isotope systematics, the latter yielding an isochron of 60 ± 32 Ma, thus constraining the timing of emplacement of the negative Ce anomalies to the past 100 Ma, possibly upon surface exposure of the Barberton Greenstone Belt to wetter conditions during the Cenozoic. Our findings constitute a cautionary tale in that even the most immobile elemental redox proxies may be more sensitive to post-depositional modification than previously thought, and demonstrate the clear advantage offered by paleoredox proxies coupled to radiometric geochronometers to enable the direct dating of ancient signals of Earth surface oxygenation.
CRIS-Team Scopus Importer:2020-07-31
Keywords: Ce anomalies; La-Ce geochronology; rare earth element mobility; trace element signatures

Post-glacial microbialite formation in coral reefs of the Pacific, Atlantic, and Indian Oceans - Heindel, Katrin; Birgel, Daniel; Brunner, Benjamin; Thiel, Volker; Westphal, Hildegard; Gischler, Eberhard; Ziegenbalg, Simone; Cabioch, Guy; Sjövall, Peter; Peckmann, Jörn (Chemical Geology, 2012)
Keywords: Coral reef; EPS-mineralization; Fertilization; Microbial mat; Sulfate-reducing bacteria; Volcanic hinterland

Post-Variscan structurally-controlled hydrothermal Zn-Fe-Pb sulfide and F-Ba mineralization in deep-seated Paleozoic units of the North German Basin: A review - Nadoll, Patrick; Sosnicka, Marta; Kraemer, Dennis; Duschl, Florian (Ore Geology Reviews, 2019)
Hydrothermal Zn-Pb-Fe sulfide and F-Ba mineralization occur as open space fillings, veins, and fracture coatings in various parts of the North German Basin in Paleozoic sedimentary rocks and volcanic units at depths of up to four kilometers. We present a petrographic and geochemical (fluid inclusion, mineral and formation water geochemistry) inventory of the mineralized zones and review the basin architecture, evolution, and stratigraphy in order to decipher the timing, extent, fluid pathways, and fluid-rock interactions associated with the ore formation. A particular focus lies on the sediment-hosted Zn-Fe-Pb sulfides in the western part of the North German Basin, the Lower Saxony Basin. Samples from hydrothermal veins from the Pre-Permian basement are also being investigated and compared to the North German Basin-style mineralization to uncover possible genetic links between them. The sediment-hosted sulfide mineralization in the Lower Saxony Basin in the Permian Stassfurt Carbonate unit (Ca2) shares many characteristics that are typical for carbonate-hosted base metal sulfide deposits such as MVT deposits. Petrographic observations, fluid inclusion and isotope data provide evidence that Zn-Fe-Pb sulfides were deposited by highly saline metal-rich basinal brines at temperatures of similar to 160 degrees C. Carbon and oxygen isotope data point toward fluid mixing augmented by structurally-controlled fluid migration during the late Cretaceous basin inversion as the primary ore precipitation mechanism with no magmatic component. In the Altmark-Brandenburg Basin, steeply-dipping F-Ba (calcite, anhydrite, quartz) veinlets in Permo-Carboniferous sandstones and volcanic units are evidence for enhanced post-Variscan structurally-controlled fluid flow. Sulfides are, apart from rare occurrences of chalcopyrite, absent. This is interpreted to reflect the paleogeographic position of the Altmark-Brandenburg Basin (deeper paleogeographic basin position without carbonate aquifers), the lack of reductants, and the predominance of nitrogen-rich fluids as documented by fluid inclusions. Measurements on formation waters from the NGB show geochemical similarities to fluid inclusions in ore and gangue minerals and could represent a potential future exploration tool for hydrothermal ore deposits. This has the potential to aid future research and exploration of deeply covered sediment-hosted deposits and to meet future mineral resources demands.
CRIS-Team WoS Importer:2019-04-09
Keywords: Fluorite; Hydrothermal; Permian; Zn-Fe-Pb sulfides; MVT; North German Basin

Postvariszische Krustenstapelung am Westrand der Boehmischen Masse; Geologische Interpretation des 9,1 km tiefen KTB-Krustenprofils - de Wall, Helga; et al. (Geowissenschaften, 1995)
UnivIS-Import:2015-03-05:Pub.1995.nat.dgeo.IGM.c3tekt.postva

Postvulkanische Rotliegend-Schwemmfächersysteme am Hunsrück-Südrand, Saar-Nahe-Becken, SW-Deutschland. - Stollhofen, Harald (Jahresberichte und Mitteilungen des Oberrheinischen Geologischen Vereins, 2007)
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LG.postvu

Potenziale und Herausforderungen der oberflächennahsten Geothermie - Müller, Johannes (Der Geothermie Kongress 2019, 2019)
Die oberflächennahe Geothermie als solches stellt einen wichtigen Baustein für eine treibhausgasfreie Wärme- und Kälteversorgung für Neu- und Bestandsgebäude dar. Durch Verwendung von oberflächennahen Geothermiesystemen kann thermische Energie aus dem Erdreich entzogen werden. Mit Hilfe einer Wärmepumpe können die saisonal beeinflussten Temperaturen des Erdreichs auf die benötigten gebäudeseitigen Verbrauchertemperaturen angehoben werden. Dies ist abhängig von der Gebäudehülle und dem Nutzerverhalten. Der Einsatz oberflächennahe Geothermie reicht von dezentral operierenden Einfamilienhäuser, über Mehrfamilienhäuser bis hin zu Quartierlösung. Die oberflächennahe Geothermie bietet die Möglichkeit Synergien verschiedener erneuerbarer Energiekonzepte sinnvoll miteinander zu verbinden. Sei es durch innovative MRS-Steuerung, sich auf natürliche Weise regenerierende Speicherlösungen oder die Vorteile eines energetisch verlustarmen kalten Nahwärmenetzes. All diese Potenziale werden innerhalb des Workshops vorgestellt und beleuchtet. Daneben wird auch auf die Herausforderungen eines individuellen Wärme- und Kältemarkts eingegangen. Das Nutzerverhalten innerhalb eines Wohnquartiers ist stark von den persönlichen Lebensgewohnheiten seiner Bewohner abhängig. Die Herausforderung besteht darin, die Versorgung und damit die Energieübertragung von der geothermischen Quelle zum Endverbraucher (und umgekehrt) durch Monitoring besser zu verstehen und durch innovative Technologien (z. B. deep learning, KI) zu optimieren. Die Herausforderungen der oberflächennahen Geothermiesysteme bestehen vor allem darin, dass die Dimensionierung der Anlagen von mehreren Parametern abhängt. Der wichtigste Parameter ist die thermische Leitfähigkeit, die von mehreren anderen physikalischen Eigenschaften des Bodens abhängt. Dies sind neben der Lagerungsdichte, die mit der Tiefe zunimmt, vor allem die Bodenfeuchte sowie die Korngrößenverteilung des Substrats. Hydrogeologische Bedingungen sind für die Gesamtbetrachtung einer Anlage essenziell, um die Regenerationspotenziale einer Anlage besser einschätzen zu können.
Keywords: oberflächennahe Geothermie; treibhausgasfreie Wärme- und Kälteversorgung

PPFG prediction in complex tectonic settings: The North Alpine thrust front and foreland basin, SE Germany - Drews, Michael; Stollhofen, Harald (2nd EAGE Workshop on Pore Pressure Prediction, 2019)
Estimation of pore and fracture pressures in complex tectonic settings, such as fold-and-thrust belts and their adjacent foreland basins, is usually challenging and often requires local calibration. The Cenozoic North Alpine Thrust Front and Foreland Basin in SE Germany provide an interesting and challenging example for such a complex system, comprising overpressured sections in the thrust belt, the overthrusted foreland sediments below the main detachment and the undeformed foreland basin. Based on the synthesis of recent research in the study area and new analyses of additional well data from the thrust front, pore and fracture pressure models will be presented for the different parts of the North Alpine Thrust Front and Foreland Basin in SE Germany. The results demonstrate, that understanding of the geological history, stress regime variations and overpressure generation are key to estimate pore and fracture pressures in complex tectonic settings, such as the North Alpine Thrust Front and Foreland Basin in SE Germany.
CRIS-Team Scopus Importer:2019-06-21

Preboreal onset of Norwegian cold-water coral growth beyond the Arctic Circle revealed by radiocarbon and U-series dating and neodymium isotopes - López Correa, Matthias; Montagna, Paolo; Joseph, Nina; Rüggeberg, Andres; Fietzke, Jan; Flögel, Sascha; Dorschel, Boris; Goldstein, Steve; Wheeler, Andrew; Freiwald, André (Quaternary Science Reviews, 2012)
Cold-water coral mounds of Lophelia pertusa are widespread across the Scandinavian shelf, which was completely ice-covered during the Last Glacial Maximum between 22 to 18ka BP. Rapid deglacial meltdown of the Fennoscandian inland ice and the retreat of its ice-streams freed most of the shelf of ice by 15ka BP. However, cold-water coral growth commenced only after the Pleistocene-Holocene transition at 11.65ka BP, when modern-like climatic patterns and oceanographic conditions were established. A tight climatic coupling has been constrained with U-series ages. Coupled 14C ages provide local reservoir ages from various gravity cores in a fjord-setting in Stjernsund at 70°N and on the open shelf in Trænadjupet at 66°N. Reinvestigation of earlier 14C coral chronologies suggests that coral ecosystems widely established themselves across the entire 3000km long Scandinavian shelf prior to 10ka BP. The earliest occurrence of Madrepora oculata at 2.4ka BP suggests a late Holocene colonization of the Norwegian shelf, which is linked to a prominent mound growth hiatus in Trænadjupet (64°N). Mound growth rates near the northern biogeographic boundary of L.pertusa with up to 614cmka -1 during certain growth periods are much higher than the previously reported fastest rates of 220cmka -1 from the Irish margin. Contemporaneous rapid fjordbasin sedimentation is slower with 63cmka -1. Matrix 14C ages overlap with coral 14C ages from the same horizon. This indicates rapid framework construction and efficient trapping of background sediment. Hiatuses are frequent in on-mound sediments and only short periods of coral growth are recorded. Coupled Δ 14C and ε Nd values indicate a persistent Holocene inflow of the North Atlantic Current in Stjernsund, but also deglacial meltwater mixing during the early Holocene prior to 9.5ka BP. Reservoir ages are overall close to the surface marine reservoir age, but ΔR is highly localized. © 2011 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LP.prebor

Precambrian gold mineralization at Djamgyr in the Kyrgyz Tien Shan: Tectonic and metallogenic implications - Konopelko, Dmitry; Klemd, Reiner; Petrov, S.V.; Apayarov, F.; Nazaraliev, B.; Vokueva, O.; Scherstén, A.; Sergeev, S. (Ore Geology Reviews, 2017)
The Djamgyr gold deposit is located within the Neoproterozoic basement of the Middle Tien Shan terrane immediately west of the Talas-Fergana fault. The deposit comprises a system of auriferous quartz veins cross-cutting the Beshtor plagiogranite. The veins are surrounded by hydrothermal alteration aureoles and are oriented parallel to the Talas-Fergana fault. The Beshtor granite sampled in the vicinity of the deposit yielded a Neoproterozoic (Tonian) U-Pb zircon age of 815 ± 6 Ma, which is the first single grain zircon age of the Middle Tien Shan basement west of the Talas-Fergana fault. Ar-Ar dating of two muscovite fractions from the alteration aureoles of the auriferous quartz veins yielded ages of 804 ± 3 and 805 ± 3 Ma suggesting that the mineralization in the Djamgyr deposit occurred during the Neoproterozoic ca. 10 m.y. after emplacement of the Beshtor granite. The structural pattern of the auriferous quartz veins and the new geochronological data, combined with the results of previous structural studies, may tentatively constrain the age of pre-existing major fault possibly marking an inherited terrane boundary in the northern part of the present-day Talas-Fergana strike-slip fault. The discovery of Precambrian gold mineralization in the Middle Tien Shan suggests re-evaluation of the metallogenic potential of its Precambrian basement that occupies significant areas west and east of the Talas-Fergana fault.
Keywords: Tien Shan (Tian Shan); Talas-Fergana fault; Djamgyr (Jamgyr) Au deposit; Neoproterozoic

Preceramic polymer derived cellular ceramics - Zeschky, Jürgen; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Lo, S.H. Jason; Kummer, Bernhard; Scheffler, Michael; Greil, Peter (Composites Science and Technology, 2003)
Ceramic foams were prepared by a self-blowing process of a poly(silsesquioxane) melt at 270 °C. The cell size, the interconnectivity density and the shape of the foam cells were adjusted by a thermal pre-curing procedure of the polymer at 200 °C. Inorganic fillers were used to modify processing behaviour and properties of the pyrolysed ceramic foam. After pyrolysis in inert atmosphere at 1200 °C ceramic composite foams with a total porosity up to 87% were obtained. The open cell ceramic foams had a mean cell diameter of 1.2 mm and a mean strut thickness of 0.2 mm. Interpenetrating phase composites (IPCs) were fabricated by infiltrating the open cellular ceramic preform with Mg alloy melt at 680 °C and a pressure of 86 MPa. The mechanical properties were found to depend on the reactions between the metal and the ceramic forming MgO, Mg2Si and Al12Mg17 as the major reaction products. The IPCs showed a significantly higher creep resistance at 135 °C, compression strength and elastic modulus compared to the unreinforced magnesium alloys. © 2003 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2003.nat.dgeo.IGM.LM.precer
Keywords: Ceramic foam

Predictability and controlling factors of overpressure in the North Alpine Foreland Basin, SE Germany: an interdisciplinary post-drill analysis of the Geretsried GEN-1 deep geothermal well - Drews, Michael C.; Hofstetter, Peter; Zosseder, Kai; Shipilin, Vladimir; Stollhofen, Harald (Geothermal Energy, 2020)
The North Alpine Foreland Basin in SE Germany is Germany's most active deep geothermal province. However, in its southern and eastern part the basin is considerably overpressured, which is a significant challenge for drilling deep geothermal wells. In this study, we combine drilling data and velocity-based pore pressure analyses with 3D basin modeling to assess the predictability and controlling factors of overpressure in the sub-regional context (area of 80 km x 50 km) around the Geretsried GEN-1 well, a deep geothermal exploration well in the southern part of the North Alpine Foreland Basin in SE Germany. Drilling data and velocity-based pore pressure analyses indicate overpressure maxima in the Lower Oligocene (Rupelian and Schoeneck Formation) and up to mild overpressure in the Upper Oligocene (Chattian) and Upper Cretaceous, except for the hydrostatically pressured northwestern part of the study area. 3D basin modeling calibrated to four hydrocarbon wells surrounding the Geretsried GEN-1 well demonstrates the dominating role of disequilibrium compaction and low permeability units related to overpressure generation in the North Alpine Foreland Basin. However, secondary overpressure generation mechanisms are likely contributing. Also, the impact of Upper Cretaceous shales, which are eroded in the northwestern part of the study area, on overpressure maintenance is investigated. The calibrated basin model is tested against the drilling history and velocity (VSP) data-based pore pressure estimate of the Geretsried GEN-1 well and reveals that pore pressure prediction is generally possible using 3D basin modeling in the North Alpine Foreland Basin, but should be improved with more detailed analysis of lateral drainage systems and facies variations in the future. The results of the study are of relevance to future well planning and drilling as well as to geomechanical modeling of subsurface stresses and deep geothermal production in the North Alpine Foreland Basin.
CRIS-Team WoS Importer:2020-07-31

Predicting extinction from fossil trajectories of geographical ranges in benthic marine molluscs - Tietje, Melanie; Kießling, Wolfgang (Journal of Biogeography, 2013)
Aim: The geographical ranges of marine taxa wax and wane in a nearly symmetrical fashion over their durations. We use this pattern as well as the age distribution of genera to predict the time of extinction of extant genera of benthic marine molluscs. Location: A global occurrence database (Paleobiology Database) of fossil marine molluscs from the Mesozoic and Cenozoic eras was used for this study. Methods: For the geographical range method, we determined the average trajectories of geographical range size for extinct genera of bivalves and gastropods. The maxima of these trajectories were used as landmarks for predicting the time of extinction for extant genera. Prediction was done by cross-multiplication, using the time elapsed until the maximum was reached and the position of the landmark. For the duration-frequency method, we calculated the time of extinction based on probabilities derived from the frequency distribution of stratigraphic ranges (durations) of all extinct genera. The accuracy and precision of predictions were tested with extinct genera and then applied to extant genera. Results: On average, bivalve and gastropod extinct genera reached their maximum geographical range size at 62% and 50% of their total duration. The accuracy of predictions ranged from -3.1 to 11.0 million years (Myr) for both groups, and the precision ranged from 13.6 to 19.5 Myr. Only a small subset of extant genera was suitable for prediction with the geographical range method, mainly because the geographical ranges of most extant genera are still rising on geological time-scales. The second method provided a similar prediction quality, but showed a substantial decrease in quality when predicting long-duration (> 100 Myr) genera. Main conclusions: The mean probability for an accurate prediction using the geographical range approach is 57% with a precision of ± 15 Myr. Prediction is possible only for genera whose peak geographical range has already elapsed (17% of extant bivalves, 16% of extant gastropods). The duration-frequency approach does not have this prerequisite and is therefore applicable to many more genera, but prediction quality declines with duration. The two methods therefore complement each other and can supplement the various efforts used to estimate extinction risk. © 2012 Blackwell Publishing Ltd.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LP.predic
Keywords: Cenozoic; Extinction; Geographical range; Marine biogeography; Marine molluscs; Mesozoic; Prediction

Predicting δ13CDIC dynamics in CCS: A scheme based on a review of inorganic carbon chemistry under elevated pressures and temperatures - Becker, Veith; Myrttinen, Anssi; Blum, Philipp; van Geldern, Robert; Barth, Johannes (International Journal of Greenhouse Gas Control, 2011)

PREDICTION OF FAULT ROCK PERMEABILITY WITH DEEP LEARNING: TRAINING DATA FROM TRANSFER SAMPLES OF FAULT CORES - Schmatz, J.; Klaver, J.; Wellmann, E.; Jiang, M.; Kraus, W.; Freitag, Simon; Hoffmann, A.; Deckert, H. (83rd EAGE Conference and Exhibition 2022, 2022)
While the influence of clay smear on the sealing properties of fault zones in siliciclastic rocks can be predicted by validated concepts such as the SGR or CSP reliable models for predicting the structural and hydraulic properties of faults in layered limestone-marl sequences do not yet exist. The main goal of our study is to analyse the development of fault sealing as a result of marl smearing in interaction with mechanical mixing as well as fracturing and cementation processes in dependence of mechanically alternating bedding and fault geometry. Oriented transfer samples of fault cores from different normal fault systems destabilised by the fault process with adjacent damage zone were successfully extracted from outcrops with Jurassic limestone in a quarry Northern Bavaria, Germany. Microanalytical tools and multiscale (m-nm) analyses workflows were developed to provide ground truth for the training of machine learning algorithms for the efficient interpretation of 2D microstructural image data. The systematic macroscopic and microstructural examination of the transfer specimens has shown that the fault zones are built up by recurrent building blocks, whose variation and expression are strongly influenced by the presence and nature of interbedded marly layers.
CRIS-Team Scopus Importer:2022-12-09

Prediction of ion selectivity by quantum chemical calculations X: A recent (personal) review - Puchta, Ralph; Begel, Svetlana; van Eldik, Rudi (Computational Chemistry, 2019)
In this review we present a simple and robust method to investigate the ion selectivity of cryptands based on quantum chemical methods. Based on easily understandable model equations and fundamental structural consideration one can rationalize or predict the observed selectivity and the underlying structural conditions. Additionally, we can learn unhampered from neighboring effects the changes in the cryptand to host the ions most effectively. The performance of this concept is demonstrated on several well known cryptands from different supramolecular groups like Lehn and others.
CRIS-Team Scopus Importer:2019-08-23
Keywords: DFT; Main group ions; Selective ion complexation; 2-Cryptands

Prehistoric and recent mass movements of the World Cultural Heritage Site Hallstatt, Austria - Moser, Michael; et al. (Environmental Geology, 2005)
Keywords: Landslide; Northern Calcareous Alps; Hallstatt; Hazard; Austria; Archaeological site; Earth flow; Cultural Heritage

Prehistoric and recent mass movements of the World Cultural Heritage Site Hallstatt, Austria - Rohn, Joachim; et al. (Environmental Geology, 2005)
Hallstatt Village, located in the Austrian Alps, is designated by the United Nations Educational, Scientific and Cultural Organization as part of the World Cultural Heritage Site "Hallstatt-Dachstein". This region is recognized for its salt deposits that have been exploited since the Neolithic period. In former times, these salt deposits were very rare and precious. Due to unfortunate bedding conditions, mass movements have been frequent in the past and continue to affect the site today. These active and inactive mass movements were mapped geotechnically to a scale of 1:5,000 and the mineralogical and mechanical properties of the main instable soft rocks were investigated. Rock spreads, rock slides, rock falls, rock topples, earth flows and earth and debris slides are the primary types of mass movements recorded. They are most frequently observed in areas affected by mining, though they may also occur in areas where no anthropogenic influence is recognized. Evidence exists in the archaeological record that indicates prehistoric mining activities were also seriously affected by the impact of mass movements. © Springer-Verlag 2005.
UnivIS-Import:2015-04-14:Pub.2005.nat.dgeo.IGM.profes_3.prehis
Keywords: Archaeological site; Austria; Cultural Heritage; Earth flow; Hallstatt; Hazard; Landslide; Northern Calcareous Alps

Preliminary Estimation of Paleoproductivity via TOC and Habitat Types: Which Method Is More Reliable? —A Case Study on the Ordovician–Silurian Transitional Black Shales of the Upper Yangtze Platform, South China - Wenbo, Su; Yongbiao, Wang; Cramer, Bradley D.; Munnecke, Axel; Zhiming, Li; Lipu, Fu (Journal of China University of Geosciences, 2008)
New total organic carbon (TOC) data from the two Ordovician-Silurian transitional graptolite-bearing black shale intervals, the Wufeng Formation and the Longmaxi Formation in Central Guizhou and West Hubei, respectively, as well as previously reported TOC data from the same intervals in other places on the Yangtze platform of South China, have been used to produce an initial estimate of the primary paleoproductivity via a conventional inverse method (i.e., R). The values of the R are estimated to be 32 (43-21) gC/(m·a) (Wufeng Formation) and 21 (27-16) gC/(m·a) (Longmaxi Formation). Also, simultaneously, the habitat types (i.e., HT; cf., BA: benthic assemblage) and their temporal and spatial changes have been documented from the same succession, and an initial estimate of the primary paleoproductivity has been produced using a forward method (i.e., R). Being bounded mainly by the peritidal to inner-shelf environment shelly-facies or mixed-facies successions with BA1 to BA3 faunas both at the top and the base, which indicates the habitat types from HT II to HT III, the biohabitat type of the two graptolite-bearing black shale intervals can be limited to HT III to HT IV, corresponding to the inner shelf to the outer shelf, with depths from roughly 60 m to 200-300 m. Based on the current data from the South China Sea and the southern part of the East China Sea, values of R should be about 100 to 400 gC/(m·a). The difference in the results via the two methods suggests that paleoproductivity estimates from the geological strata need to be made cautiously, with particular attention paid to the paleogeographic setting, oxic-anoxic conditions, as also the preservation factor of organic carbon. © 2008 China University of Geosciences.
Keywords: primary productivity; black shale; TOC; habitat type (HT); Ordovician; Silurian transition; South China

Preliminary magnetic susceptibility characteristics of the Bharati promontory (Grovness Peninsula), Larsemann Hills, Prydz Bay region, East Antarctica - Pandit, Manoj K.; de Wall, Helga (Journal of the Geological Society of India, 2014)
Keywords: Bharati promontory; East Antarctica; Gneisses; Larsemann Hills; Magnetic susceptibility

Preliminary magnetic susceptibility results on the Neoproterozoic Mt.Abu granite, NW-Indian craton: correlation between magnetic fabric and deformation - de Wall, Helga; Pandit, M. K. (Geotectonic Research, 2007)
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.c3tekt.lowfie

Pre-mass extinction decline of latest Permian ammonoids - Kießling, Wolfgang; Schobben, Martin; Ghaderi, Abbas; Hairapetian, Vachik; Leda, Lucyna; Korn, Dieter (Geology, 2018)
The devastating end-Permian mass extinction is widely considered to have been caused by large-scale and rapid greenhouse gas release by Siberian magmatism. Although the proximate extinction mechanisms are disputed, there is widespread agreement that a major extinction pulse occurred immediately below the biostratigraphically defined Permian-Triassic boundary. Our statistical analyses of stratigraphic confidence intervals do not comply with a single end-Permian extinction pulse of ammonoids in Iran. High turnover rates and extinction pulses are observed over the last 700 k.y. of the Permian period in two widely separated sections representative of a larger area. Analyses of body sizes and morphological complexity support a gradual decline over the same interval. Similar pre-mass extinction declines and disturbances of the carbon cycle have sometimes been reported from other regions, suggesting a widespread, but often overlooked, environmental deterioration at a global scale, well before the traditional main extinction pulse.

Present and future challenges of urban systems affected by seawater and its intrusion: the case of Venice, Italy - Di Sipio, Eloisa; Zezza, Fulvio (Hydrogeology Journal, 2011)
Keywords: Coastal aquifers; Salinization; Sea salt damage; Non destructive techniques; Italy

Pressure-temperature evolution during two granulite-facies metamorphic events (2.62 and 2.02 Ga) in rocks from the Central Zone of the Limpopo Belt, South Africa - Brandt, Sönke; Klemd, Reiner; Li, Qiuli; Kröner, Alfred; Brandl, Guenther; Fischer, Andreas; Bobek, Patrick; Zhou, Tian (Precambrian Research, 2018)
The Central Zone of the Limpopo Belt in southern Africa is a classical example of a polymetamorphic terrane that experienced three metamorphic events at 3.22 Ga (M1), 2.66–2.61 Ga (M2) and 2.02 (M3). However, the geodynamic significance of these events is controversial as their P-T evolution was poorly constrained. We present new petrological and geochronological data for the M2 and M3 events. The Neoarchean M2 event is well-preserved in samples from a newly discovered enclave of supracrustal and magmatic rocks in the 2.612 Ga Bulai pluton that shielded the enclave against a Paleoproterozoic M3 overprint, which is dominant in rocks exposed outside the pluton. P-T pseudosection modelling for migmatitic Grt-Crd metapelites from the enclave and the rock sequence outside the pluton indicates an opposite metamorphic evolution, a counterclockwise P-T path for M2 but a clockwise path for M3. Spinel-quartz assemblages in the enclave metapelites record early heating to UHT conditions (ca. 930 °C, 5.5 kbar) at intermediate crustal levels. The peak-pressure M2-assemblage garnet-cordierite-sillimanite-K-feldspar-plagioclase-quartz ± rutile formed at ca. 860 °C and 7.5 kbar during a moderate pressure increase. Cordierite coronas around garnet record subsequent decompression. We interpret the counterclockwise P-T evolution during M2 to result from convergence of the Zimbabwe and Kaapvaal Cratons, which has led to subduction of oceanic lithosphere beneath the Zimbabwe Craton. Subsequent slab retreat has caused asthenosphere upwelling, thereby inducing delamination of the lithospheric mantle. Intrusion of hot asthenospheric material beneath the crust induced early UHT metamorphism at mid-crustal levels. The subsequent moderate pressure increase was related to the ensuing collision of the cratons. Post-peak decompression records incorporation of the enclave into the Bulai pluton melt and uplift in the ascending granitoid melt. The peak M3-assemblage garnet-cordierite-sillimanite-K-feldspar-rutile-plagioclase-quartz formed in metapelites occurring outside the pluton during near-UHT conditions (ca. 880 °C, 7.5 kbar). Cordierite coronas around garnet record subsequent decompression. New growth of garnet and sillimanite at the expense of cordierite documents late near-isobaric cooling to <700 °C. The resulting clockwise P-T path for M3 granulite-facies metamorphism is interpreted to record an intracontinental Paleoproterozoic transpressional orogeny within the consolidated Kaapvaal-Zimbabwe Craton, which was induced by far-field tectonic processe
Keywords: Limpopo Belt; Pseudosection; P-T path; Granulite; Neoarchean; Delamination

Pressure-temperature evolution of blueschist facies rocks from Sifnos, Greece, and implications for the exhumation of high-pressure rocks in the Central Aegean - Schmädicke, Esther; et al. (Journal of Metamorphic Geology, 2003)
Keywords: Exhumation; Cyclades; Pseudosection; High-pressure metamorphism; Sifnos

Prevailing anoxia in the Kungurian (Permian) of South China: Possible response to divergent climate trends between the tropics and Gondwana - Liu, Chao; Jarochowska, Emilia; Du, Yuansheng; Munnecke, Axel; Dai, Xianduo (Gondwana Research, 2017)
Keywords: Early–Middle Permian; Icehouse–greenhouse climate transition; Ocean stagnation; Primary productivity

Primary versus diagenetic isotope signals in Pseudorthoceras sp. from the Buckhorn Asphalt Quarry (mid-Pennsylvanian, Oklahoma) - a detailed study of cameral deposits - Seuß, Barbara; Titschack, Jürgen; Nützel, Alexander (Annual Meeting of the Paläontologische Gesellschaft, 2010)
Oxygen and carbon stable isotope studies of well-preserved fossils present an important data source for palaeoclimatic studies. Commonly, the older the fossils, the less good they are preserved. The Buckhorn Asphalt Quarry Lagerstätte from the mid-Pennsylvanian of Oklahoma is one of the few Palaeozoic examples, where original (metastable) shell material, such as aragonite and high magnesium calcite (HMC) is found, due to their early post-mortal hydrocarbon impregnation. The Buckhorn Asphalt Quarry is characterised by fossiliferous sediments soaked with hydrocarbons, which commonly prevented diagenesis. This study presents microstructural, mineralogical and stable isotope data from Pseudorthoceras sp. (two chambers with their cameral deposits). Therefore data from thin section analysis, scanning electron microscope (SEM) combined with an energy disperse x-ray (EDX), and x-ray diffraction (XRD) with a general area detection diffraction system (GADDS) analysis were combined. XRD-GADDS is a relatively new method to investigate the shells mineralogy and allows the non-destructive, site-specific identification of mineral phases. Altogether seven microstructures were differed in the sections drilled for isotope dating. These could be divided into two primary mineralogies, aragonite and HMC. We don’t have any knowledge of cameral deposits with a HMC mineralogy or found any evidence of this in literature. The only partially unaltered preserved microstructure is the nacre of the septum. All other microstructures exhibit a partial or complete alteration to low magnesium calcite (LMC), or in case of the primary HMC to LMC and dolomite. According to the isotope signature the diagenesis took place most likely in the meteoric environment. The partial diagenesis results in isotope values, which plot along a linear trend between the two end-members. This linear trend could easily be misinterpreted as kinetic vital effect, if no sorrow phase control was performed. The isotopic signal of the primary nacre of the septum suggest a normal marine environment for these nektonic molluscs, with tropical temperatures of 14°C to 15°C (δ18Oseawater 1.5 ‰, a typical value for modern tropical marginal seas

Primitive andesites from the Taupo Volcanic Zone formed by magma mixing - Beier, Christoph; Haase, Karsten; Brandl, Philipp; Krumm, Stefan (Contributions To Mineralogy and Petrology, 2017)
Andesites with Mg# >45 erupted at subduction zones form either by partial melting of metasomatized mantle or by mixing and assimilation processes during melt ascent. Primitive whole rock basaltic andesites from the Pukeonake vent in the Tongariro Volcanic Centre in New Zealand’s Taupo Volcanic Zone contain olivine, clino- and orthopyroxene, and plagioclase xeno- and antecrysts in a partly glassy matrix. Glass pools interstitial between minerals and glass inclusions in clinopyroxene, orthopyroxene and plagioclase as well as matrix glasses are rhyolitic to dacitic indicating that the melts were more evolved than their andesitic bulk host rock analyses indicate. Olivine xenocrysts have high Fo contents up to 94%, δO of +5.1‰, and contain Cr-spinel inclusions, all of which imply an origin in equilibrium with primitive mantle-derived melts. Mineral zoning in olivine, clinopyroxene and plagioclase suggest that fractional crystallization occurred. Elevated O isotope ratios in clinopyroxene and glass indicate that the lavas assimilated sedimentary rocks during stagnation in the crust. Thus, the Pukeonake andesites formed by a combination of fractional crystallization, assimilation of crustal rocks, and mixing of dacite liquid with mantle-derived minerals in a complex crustal magma system. The disequilibrium textures and O isotope compositions of the minerals indicate mixing processes on timescales of less than a year prior to eruption. Similar processes may occur in other subduction zones and require careful study of the lavas to determine the origin of andesite magmas in arc volcanoes situated on continental crust.
Keywords: Crustal magmatic processes; Magma mixing; Primitive andesites; Subduction zones; Taupo Volcanic Zone

Productivitiy and bottom water redox conditions on both sides of the Eovariscan Belt: constraints from trace element geochemistry. - Joachimski, Michael; et al. (Developments in Palaeontology and Stratigraphy, 2005)
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LG.produc

Productivity controlled cold-water coral growth periods during the last glacial off Mauritania - Frank, Norbert; Wienberg, Claudia; Hebbeln, Dierk; López Correa, Matthias; Douville, Eric; Freiwald, André; Eisele, Markus (Marine Geology, 2011)
Cold-water corals are widely distributed along the Atlantic continental margin with varying growth patterns in relation to their specific environment. Here, we investigate the long-term development of cold-water corals that once thrived on a low-latitude (17°40'N) cold-water coral mound in the Banda Mound Province off Mauritania during the last glacial-interglacial cycle. U/Th dates obtained from 20 specimens of the cold-water coral Lophelia pertusa, revealed three distinct periods of coral growth during the last glacial at 65 to 57. kyr. BP, 45 to 32. kyr. BP and 14. kyr. BP, thus comprising the cool periods of Marine Isotopic Stages (MIS) 2-4. These coral growth periods occur during periods of increased productivity in the region, emphasizing that productivity seems to be the major steering factor for coral growth off Mauritania, which is one of the major upwelling regions in the world. This pattern differs from the well studied coral mounds off Ireland, where the current regime predominantly influences the prosperity of the cold-water corals. Moreover, coral growth off Ireland takes place during rather warm interglacial and interstadial periods, whereas off Mauritania coral growth is restricted to glacial and stadial periods. However, the on-mound sedimentation patterns off Mauritania largely resemble the observations reported from the Irish mounds. The bulk of the preserved sediments derives from periods of coral growth, whereas during periods without corals hardly any net sedimentation or mound growth took place. © 2011 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LP.produc
Keywords: Banda Mound Province; Carbonate mounds; Cold-water corals; Lophelia; NW-Africa; Primary productivity

Progetto ITER: il miglioramento dell'efficienza termica degli scambiatori di calore orizzontale - Di Sipio, Eloisa; Bertermann, David (Convegno finale Progetto GEOTERM - GEOSCAMBIO IN TERRITORIO ALPINO, 2016)

Progressive changes in crystallographic textures of biominerals generate functionally graded ceramics - Wallis, David; Harris, Joseph; Böhm, Corinna; Wang, Di; Zavattieri, Pablo; Feldner, Patrick; Merle, Benoit; Pipich, Vitaliy; Hurle, Katrin; Leupold, Simon; Hansen, Lars N.; Marin, Frederic; et al. (Materials Advances, 2021)
Biomineralizing organisms are widely praised for their ability to generate structural materials with exceptional crystallographic control. While earlier studies highlighted near-to single-crystalline biominerals, complex polycrystalline features are more widespread yet challenging to account for. Here, we propose that biominerals whose crystal texture varies with depth are functionally graded materials. Using the exemplary case of the nacro-prismatic pearl oyster Pinctada margaritifera, we demonstrate systematic textural changes in a biogenic ceramic. This bivalve employs three synergistic mechanisms to generate a texture gradient across its outer calcitic shell layer. This prismatic layer transitions from an initially weakly-textured to a strongly-textured material. Such changes in texture cause a variation in Young's modulus normal to the shell, owing to the anisotropic mechanical properties of the composing crystallites. Based on finite-element simulations and indentation experiments on the bivalve shell, we conclude that such graded bioceramics yield intrinsic toughening properties similar to those found in compositionally-graded synthetic materials. Notwithstanding, the gradation concept of Pinctada margaritifera is unparalleled among synthetic materials as it rests solely upon elastic anisotropy, making oyster shells potential blueprints for future bioinspired functional materials and damage-resistant ceramics.
CRIS-Team WoS Importer:2022-01-14

Progressive Changes in Magma Transport at the Active Serreta Ridge, Azores - Romer, René; Beier, Christoph; Haase, Karsten; Kluegel, A.; Hamelin, C. (Geochemistry Geophysics Geosystems, 2019)
Volcanism in the Eastern Azores Plateau occurs at large central volcanoes and along subaerial and submarine fissure zones, resulting from a mantle melting anomaly combined with transtensional stresses. Volcanic structures are aligned WNW-ESE and NW-SE, reflecting two tectonic stress fields that control the direction of lateral melt transport. Terceira Island is influenced by both stress fields, dividing the island into an eastern and western part. Several submarine volcanic ridges with variable orientations are located west of Santa Bárbara, the youngest central volcano on Terceira. Major, trace element and Sr-Nd-Pb-Hf isotope compositions from submarine lavas and glasses, in part associated with the 1998–2001 Serreta Ridge eruption, vary between different lava suites, suggesting a formation from different mantle sources. Submarine lavas are more primitive than those from Santa Bárbara volcano, indicating that they are not laterally connected with the shallow magma reservoir located in 2- to 5-km depth beneath the central volcano. Mineral thermobarometric data suggest that the older Serreta magmas were laterally transported at depths >5 km from Santa Bárbara predominantly in WNW direction. We propose that lithospheric extension controls magma transport from the central volcano to Serreta Ridge. The youngest Serreta lavas differ from Santa Bárbara and other submarine ridges in having less radiogenic Pb and higher Hf isotope ratios representing a new magma pulse ascending from the mantle. We conclude that lateral magma transport and the morphology of volcanic ridges are controlled by tectonic stresses in the lithosphere, whereas vertical melt transport is initiated by processes in the mantle.
CRIS-Team Scopus Importer:2019-12-10
Keywords: Azores; evolution; magmatic; melt transport; ocean island; tectonic

Proliferation and demise of deep-sea corals in the Mediterranean during the Younger Dryas - McCulloch, Malcolm; Taviani, Marco; Montagna, Paolo; López Correa, Matthias; Remia, Alessandro; Mortimer, Graham (Earth and Planetary Science Letters, 2010)
Uranium-series and radiocarbon ages are reported for deep-sea corals Madrepora oculata, Desmophyllum dianthus, Lophelia pertusa and Caryophyllia smithii from the Mediterranean Sea. U-series dating indicates that deep-sea corals have persisted in the Mediterranean for over 480,000years, especially during cool interstadial periods. The most prolific period of growth however appears to have occurred within the Younger Dryas (YD) period from 12,900 to 11,700years BP followed by a short ( 330years) phase of post-YD coral growth from 11,230 to 10,900years BP. This indicates that deep-sea corals were prolific in the Mediterranean not only during the return to the more glacial-like conditions of the YD, but also following the rapid deglaciation and transition to warmer conditions that followed the end of the YD. Surprisingly, there is a paucity Last Glacial Maximum (LGM) coral ages, implying they were largely absent during this period when cold-water conditions were more prevalent. Radiocarbon ages show that the intermediate depth waters of the Mediterranean generally had increment14C compositions similar to surface waters, indicating that these waters were extremely well ventilated. The only exception is a narrow period in the YD (12,500±100years BP) when several samples of Lophelia pertusa from the Ionian Sea had increment14C values falling significantly below the marine curve. Using a refined approach, isolation ages (τisol) of 300years to 500years are estimated for these intermediate (800-1000m) depth waters relative to surface marine waters, indicating a reduction or absence of deep-water formation in the Ionian and adjacent Adriatic Seas during the YD. Contrary to previous findings, we find no evidence for widespread intrusion of low increment14C Atlantic waters into the Mediterranean. Prolific growth of deep-sea corals in the Mediterranean ended abruptly at 10,900years BP, with many of the coral-bearing mounds on the continental slopes being draped in a thin veneer of mud. Their demise is attributed to a number of factors, including the direct loss of habitat due to high sedimentation that accompanied glacial meltwater pulses, together with rising temperatures that would have finally pervaded the deeper water of the Mediterranean following the onset of Holocene warming. © 2010 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LP.prolif
Keywords: Deep-sea corals; Demise; Environment; Prolific; U-series dating; Younger Dryas

Promoting origination - Kießling, Wolfgang (Nature Geoscience, 2010)
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LP.promot

Proterozoic evolution of the North Atlantic - Arctic Caledonides: Insight from detrital zircon analysis of metasedimentary rocks from the Pearya Terrane, Canadian High Arctic. - Malone, Shawn J.; Mcclelland, William C.; von Gosen, Werner; Piepjohn, Karsten (Journal of Geology, 2014)
The Pearya Terrane, recognized as the only exotic terrane along the Canadian Arctic margin, includes a Neoproterozoic–early Paleozoic basinal or passive-margin metasedimentary sequence that is structurally juxtaposed with arc-related Paleozoic rocks and a metamorphic basement complex containing early Neoproterozoic orthogneiss. The Neoproterozoic siliciclastic sequence is similar to other clastic sections formed at the breakup of Rodinia, but its paleogeographic origin and crustal affinity are uncertain. Detrital zircon age spectra from seven samples reveal three groups: Group A, with numerous peaks at c. 1100–1800 Ma and the youngest population at c. 1020 Ma; Group B, defined by a dominant c. 970 Ma age peak; and Group C, with dominant peaks from c. 970–1800 Ma and a small population of c. 635–710 Ma grains. Spectra from Group A resemble data from the latest Mesoproterozoic units in Svalbard, East Greenland, and the Scandinavian Caledonides, with the ubiquitous Mesoproterozoic ages observed in all these regions compatible with derivation from the Grenville-Sveconorwegian Orogen of Laurentia and Baltica. The dominance of 930–970 Ma ages in Group B reflects input from magmatic rocks of this age in Pearya and Sval-bard, while the 635–710 Ma ages observed in Group C overlap with magmatic ages observed in the Arctic Alaska–Chukotka Terrane and units in the Taimyr-Timanide region. The Neoproterozoic siliciclastic strata of the Pearya Terrane originated distal to northeastern Laurentia, in a position similar to that of the constituent terranes of Svalbard and the Eleonore Bay Supergroup of East Greenland, and they record deposition along a Neoproterozoic convergent margin active during the prolonged breakup of Rodinia.
UnivIS-Import:2015-10-26:Pub.2014.nat.dgeo.IGM.LG.proter

Provenace, distributiion and trade of the local building materials in the Sarno River Plain (Campania) from the 6th Century BC to AD 79. - Kastenmeier, Pia; Ballasone, Pina; Boni, Maria; Di Maio, Ernesto; Joachimski, Michael (ASMOSIA X. Proceedings of the 10th International Conference, 2014)
UnivIS-Import:2015-07-08:Pub.2014.nat.dgeo.IGM.LG.proven

Provenance of Palaeozoic sediments during subduction of Palaeotethys: detrital zircon ages and the analysis of olistoliths from Chios Island, Greece. - Meinhold, Guido; Lehnert, Oliver; Reischmann, Thomas; Kostopoulos, Dimitrios; Matukov, Dmitry; Sergeev, Sergej (Palaeogeography, Palaeoclimatology, Palaeoecology, 2008)
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LG.proven

Provenance of Tertiary volcanoclastic sediment in NW Thrace (Bulgaria): Evidence from detrital amphibole and pyroxene geochemistry - Caracciolo, Luca; et al. (Sedimentary Geology, 2016)
Detrital heavy mineral and bulk rock geochemistry and a review of sandstone petrographic data have been used to investigate the post-collisional effusive magmatism that followed the closure of the Vardar Ocean and the generation of volcanic sediments in a complex and compositionally variable volcanic region. Available petrographic data gives evidence of contributions from three key source areas corresponding to the three main tectonic units: the structurally lower Gneiss-Migmatite Complex (Byala Reka-Kechros and Kesebir-Kardamos domes) and the upper Variegated (Kimi) Complex, both fringed by the low-to-medium-grade Mesozoic rocks of the Circum-Rhodope Belt. Besides the deposition of siliciclastic material, volcanic contributions from both, intermediate and acid products represent an important source of sediment in the area. Despite dominant intermediate to acid volcanic products, volcanic lithic fragments in sandstones (microlithic, lathwork and brown vitric textures) indicate main inputs from intermediate and basic-intermediate products generating questions on the interpretation of volcanic detritus in reconstruction of provenance. Detrital amphibole and pyroxene chemistry is used to characterise the supply of volcanic material as well as the dispersal mechanisms and understand the role played by each of the volcanic centers present in the area in the infill of the north-western Thrace basin. Amphibole chemistry reveals high compositional heterogeneity according to both compositional variability of the numerous volcanic centres active at the time of deposition and presence of metamorphic amphibole. Al-4 and Al-T apfu values indicate that most of the amphiboles from the NERZ are not of volcanic origin and their presence can only be attributed to the numerous amphibolite facies metamorphic rocks abundantly documented in the area. Detrital amphibole compositions from the ZKVS indicate major contributions from the Iran Tepe and Zvedzel volcanoes. Analysed detrital clinopyroxenes from the NERZ are mostly diopside-augite, with no hedenbergite or Fe-augite detected. The Al-4/Al-6 ratio is comparable with compositions of volcanic pyroxenes from the Momchilgrad-Arda (ZKVS) region and products from the pre-caldera phase of the Borovitza. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: Single grain geochemistry; Provenance analysis; Thrace Basin; Rhodope; Volcaniclastic sedimentation; Eastem Mediterranean basin

Pseudotachylyte in muscovite-bearing quartzite: Coseismic friction-induced melting and plastic deformation of quartz - Bestmann, Michel; Pennacchioni, Giorgio; Frank, Gerhard; Göken, Mathias; de Wall, Helga (Journal of Structural Geology, 2011)
Thin (0.5–2 mm thick) pseudotachylyte veins occur within muscovite-bearing ( 10% volume), amphibolite-facies quartzites of the Schneeberg Normal Fault Zone (Austroalpine, Southern Tyrol, Italy). Pseudotachylytes are associated with precursor localized plastic microshear zones (50–150 extgreekmm thick) developed sub-parallel to the host-rock foliation and with conjugate sets oriented at a high angle to the foliation. Such microshear zones are characterized by recrystallization to ultrafine-grained (1–2 extgreekmm grain size) mosaic aggregates of quartz showing a transition from a host-controlled to a random crystallographic preferred orientation towards the shear zone interior. Subsequent coseismic slip mainly exploited these microshear zones. Microstructural analysis provides evidence of extensive friction-induced melting of the muscovite-bearing quartzite, producing a bimodal melt composition. First, the host-rock muscovite was completely melted and subsequently crystallized, mainly as K-feldspar. Then, about 60% volume of the ultrafine-grained quartz underwent melting and crystallized as spherulitic rims (mostly consisting of quartz ± Ti ± Fe) around melt-corroded quartz clasts. The two melts show immiscibility structures in the major injection veins exploiting microshear zones at high angles to the quartzite foliation. In contrast, they were mechanically mixed during flow along the main fault veins.
WW1::896

Putative ichnogenus Paralanicichnites Ghare and Badve 1981 from the Palaeogene of the Kachchh Basin (India) is a coral - Kulkarni, Kantimati G.; Sikilkar, Namra (Annales Societatis Geologorum Poloniae, 2020)
Structures, reported as the trace fossil, Paralanicichnites conflueris, were described from the Palaeogene rocks of the Kachchh (Kutch) District, Gujarat State, India, by Ghare and Badve as a new ichnogenus and ichnospecies. Restudy of the type specimens revealed that the form described as a burrow in fact is a scleractinian coral, as evidenced by its phaceloid morphology, septate calcareous exoskeleton, and twelve primary septa. It appears that there is also confusion regarding the exact geological formation, from which the specimens under consideration were taken by the original authors, as well as the age assigned by them.
CRIS-Team WoS Importer:2020-09-11

Putting the F into FBD analysis: tree constraints or morphological data? - Barido-Sottani, Joëlle; Pohle, Alexander; De Baets, Kenneth; Murdock, Duncan; Warnock, Rachel (Palaeontology, 2023)
The fossilized birth–death (FBD) process provides an ideal model for inferring phylogenies from both extant and fossil taxa. Using this approach, fossils are directly integrated into the tree, leading to a statistically coherent prior on divergence times. Since fossils are typically not associated with molecular sequences, additional information is required to place fossils in the tree. We use simulations to evaluate two different approaches to handling fossil placement in FBD analyses: using topological constraints, where the user specifies monophyletic clades based on established taxonomy, or using total-evidence analyses, which use a morphological data matrix in addition to the molecular alignment. We also explore how rate variation in fossil recovery or diversification rates impacts these approaches. We find that the extant topology is well recovered under all methods of fossil placement. Divergence times are similarly well recovered across all methods, with the exception of constraints which contain errors. We see similar patterns in datasets which include rate variation, however, relative errors in extant divergence times increase when more variation is included in the dataset, for all approaches using topological constraints, and particularly for constraints with errors. Finally, we show that trees recovered under the FBD model are more accurate than those estimated using non-time calibrated inference. Overall, we show that both fossil placement approaches are reliable even when including uncertainty. Our results underscore the importance of core taxonomic research, including morphological data collection and species descriptions, irrespective of the approach to handling phylogenetic uncertainty using the FBD process.
CRIS-Team Scopus Importer:2023-11-24
Keywords: fossilized birth–death; morphological data; phylogenetic inference; taxonomy; topological constraints; total-evidence

Pyrite chemistry: A new window into Au-Te ore-forming processes in alkaline epithermal districts, Cripple Creek, Colorado - Keith, Manuel; Smith, Daniel J.; Doyle, Keiran; Holwell, David A.; Jenkin, Gawen R.T.; Barry, Tiffany L.; Becker, Joseph; Rampe, Jason (Geochimica Et Cosmochimica Acta, 2020)
Tellurium has a wide variety of applications, most importantly in the solar energy industry and is eco-toxicologically significant; however, the magmatic-hydrothermal processes causing the pronounced Te enrichment together with Au in some epithermal districts are still poorly constrained. Hydrothermal and alkaline magmatic activity in post-subduction environments are suggested to be a critical component in the evolution of this Te-rich sub-class of low-sulfidation epithermal deposits. Cripple Creek represents an example for a world-class low-sulfidation epithermal Au-Te anomaly in the continental crust. This area represents a natural laboratory to investigate the processes of ore-formation and Au-Te enrichment in alkaline igneous rock-hosted epithermal systems. Here, we present the first micro-analytical approach that combines petrographic observations with in situ LA-ICP-MS analyses and trace element mapping to define the key ore-forming processes of Au and Te in the Cripple Creek epithermal complex. Two main styles of mineralization can be distinguished: (1) low-grade Au disseminated pyrite-rich ores in the permeable brecciated host rocks and (2) high-grade quartz-fluorite veins rich in calaverite (AuTe2), coloradoite (HgTe), petzite (Ag3AuTe2), altaite (PbTe) and native Au. Pyrite trace element mapping revealed distinct variations and decoupling of elements (Au-Te) and element pairs (Au-As vs. Co-Ni) within and between different sites in the epithermal district. This is reflected by the concentric/growth zoning of these elements in pyrite that were interpreted to be caused by fluid boiling associated with the deposition of the low-grade disseminated host rock ores at temperatures between 220 and 350 °C leading to the precipitation of Au, As, Co and Ni from the liquid phase and the preferential partitioning of Te into the vapor phase. The subsequent condensation of the Te-rich vapors in metal-bearing meteoric waters led to the Te precipitation being decoupled from Au in the low-grade ores. The high-grade Au-Te mineralization was likely initiated by the influx of magmatically derived oxidized fluids. Subsequently, fluid temperatures dropped due to mixing with meteoric waters resulting in fluid boiling under low pressure conditions at shallower crustal levels (<1000 m) compared to the low-grade ores. Elevated fO2 minimized the loss of Te to the vapor phase and the strong boiling conditions at lower fluid temperatures (105–200 °C) caused the contemporaneous precipitation of Au and Te in the high-grade veins.
CRIS-Team Scopus Importer:2020-02-25
Keywords: Epithermal Au-Te deposits; Fluid boiling; LA-ICP-MS analysis; Telluride mineralogy; Trace elements in pyrite

Pyrophosphate ions inhibit calcium phosphate cement reaction and enable storage of premixed pastes with a controlled activation by orthophosphate addition - Weichhold, Jan; Götz-Neunhoeffer, Friedlinde; Hurle, Katrin; Gbureck, Uwe (Ceramics International, 2022)
The standard preparation routine of a calcium phosphate cement includes mixing a solid and a liquid component (reactive cement powder and mixing liquid) in an open bowl at the operating theatre. This poses the risk of preparation-related deviations of the resulting properties when the cements are mixed by different persons. Hence, facilitating this mixing procedure is highly desirable. It can be achieved by application of premixed cement pastes: The mixing liquid and a stable suspension of the cement powder are assembled and mixed in a special syringe, minimizing the impact of these preparation-related effects. In this study, a suspension of reactive α-tricalcium phosphate powder in water was stabilized by sodium pyrophosphate decahydrate (PP). Controlled activation of these premixed pastes was then accomplished by adding a concentrated Na2HPO4/NaH2PO4 (Na2/Na) solution. Systematic assessment of the activation mechanism, including the effect of the PP concentration and the amount of Na2/Na added, was performed by isothermal calorimetry, quantitative in-situ X-ray diffraction, rheological characterization and automated Gillmore needle measurements at 37 °C. Premixed pastes with addition of at least 0.05 wt% PP were successfully stabilized for up to 2 weeks at 25 °C, and even 4 weeks at 4 °C. This pre-storage had no significant impact on the setting performance of the pastes. Increasing the PP concentration at constant Na2/Na amount systematically retarded the setting reaction, while an elevated quantity of Na2/Na addition at constant PP concentration resulted in an acceleration. Based on these results, a composition stabilized with 0.05 wt% PP and activated with 20.8 vol% Na2/Na related to the amount of liquid in the premixed pastes appears ideal with respect to the desired setting performance.
CRIS-Team Scopus Importer:2022-04-22
Keywords: Apatite (D); Biomedical applications (E); Premixed cement pastes; X-ray methods (B)

Quantification of a mixture of synthetic Alite and Belite by the Rietveld method - Neubauer, Jürgen; Sieber, Roland (Materials Science Forum, 1996)
Alite and beute are the main components in ordinary portland cement. The quantification by X-ray diffraction methods is very difficult due to the wide range of overlapping reflections. The presented investigations deal with the quantification by fullprofile refinement. To get good structure data of alite and belite both were synthesized in a laboratory furnace at 1400°C. Their chemical composition was the same as that of alite and belite of technically produced cement clinker (modified composition proposed by Taylor 1990 [1]). X-ray investigation of alite shows best fits to the monoclinic superstructure published by Nishi & Takeuchi (1985) [2]. Belite could be described by the structure data of Jost et al. (1977) [3]. Both structures were refined by the Rietveld PC software of Wiles and Young modified by Howard. Afterwards synthetic alite and belite were mixed in different ratios and quantified by the same software. Three different mixtures show a smaller deviation from the input than 1 wt.%.
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LM.quanti_9
Keywords: Portland Cement; Quantification; Rietveld Method; Synthetic Mixture

Quantification of groundwater infiltration into urban sewer systems using stable isotopes - Penckwitt, Jan; van Geldern, Robert; Hagspiel, Burkard; Packebusch, Birgit; Mahr, Alexander; Burkhardt, Klaus; Barth, Johannes (Grundwasser, 2016)

Quantification of groundwater-seawater interaction in a coastal sandy aquifer system: A study from Panama, Sri Lanka - Chandrajith, Rohana; Chaturangani, Dinusha; Abeykoon, Sumith; Barth, Johannes; van Geldern, Robert; Edirisinghe, E. A. N. V.; Dissanayake, C. B. (Environmental Earth Sciences, 2014)

Quantification of long-term wastewater fluxes at the surface water/groundwater-interface: An integrative model perspective using stable isotopes and acesulfame - Engelhardt, I.; Barth, Johannes; Bol, Roland; Schulz, M.; Ternes, T. A.; Schueth, C.; van Geldern, Robert (Science of the Total Environment, 2014)

Quantification of sediment transport by rockfall and rockslide processes on a proglacial rock slope (Kaunertal, Austria) - Vehling, Lucas; Baewert, H.; Glira, P.; Moser, Michael; Rohn, Joachim; Morche, David (Geomorphology, 2017)
Rockfalls and rockslides are significant geomorphic processes on high alpine proglacial rock slopes. In this study, we quantitatively evaluate sediment transport on a recently deglaciated rock slope that is directly connected to the shrinking Gepatschferner glacier, by multi-temporal terrestrial and airborne LiDAR observations. According to the LiDAR measurements, sediment transport by gravitational mass movements on this single proglacial rock slope (0.2 km2) yielded 159 GJ/a geomorphic work. The most significant part (141 GJ/a) was released by rockfall while 18 GJ/a were performed by the sliding activity of a 1,250,000 m3 large unstable rock mass. The results indicate that slope development and talus formation in proglacial environments may be a rapid process despite of being caused by continuous rockfall activity over several millennia. © 2016 Elsevier B.V.
Keywords: glacier; landslide; lidar; proglacial environment; rockfall; sediment transport; Austria; Kaunertal; Tyrol

Quantification of small magnitude rockfall processes at a proglacial high mountain site, Gepatsch glacier (Tyrol, Austria) - Vehling, Lucas; Moser, Michael; Rohn, Joachim (Zeitschrift für Geomorphologie, 2016)
Keywords: Proglacial geosystem; Rockfall collectors; Rockfall intensity

Quantification of wall surface heterogeneity and its influence on species diversity at medieval castles - implications for the environmentally friendly preservation of cultural heritage - Steinbauer, Manuel; Gohlke, Andreas; Mahler, Christine; Schmiedinger, Andreas; Beierkuhnlein, Carl (Journal of Cultural Heritage, 2013)
Historic buildings are important for cultural history and provide a variety of habitats for animals and plants. Especially structural heterogeneity of wall surfaces is perceived to support biological diversity. Nevertheless, in traditional approaches goals of biodiversity preservation and monument restoration are perceived to interfere and to be mutually exclusive. As a consequence, priority is often given to constructional restoration accepting the loss of local populations and biodiversity. At walls of medieval castles, including an experimental restoration project where conventional and less intensive restoration techniques were applied, we relate species composition and richness to wall properties. Especially wall surface structure is quantified using a novel approach. The study focuses on lichens, mosses and vascular plants. Boosted regression tree analyses and non-metric multidimensional scaling techniques are applied to detect the influence of abiotic site conditions on biodiversity. We find species richness to be promoted by wall surface heterogeneity. However, species composition is more affected by restoration approaches than species richness. Lichen composition varies considerably while vascular plants and mosses are less affected by wall properties. We suggest strategies that are combining both societal targets, the preservation of historic monuments and of species diversity. Careful restoration is capable of supporting both, the maintenance of cultural heritage and of rare and unique anthropogenic habitats. Wall surface heterogeneity needs to be witnessed for both aspects as it affects both species composition as well as the effectiveness of cleaning methods.
Keywords: Biodegradation; Biodeterioration; Historic buildings; Monuments; Nature conservation; Wall vegetation

Quantifizierung von Mischungen aus synthetischem Alit und Belit mit Hilfe der Rietveld Methode - Neubauer, Jürgen; Sieber, Roland; Kuzel, Hans Jürgen (European Journal of Mineralogy, 1995)
UnivIS-Import:2015-03-05:Pub.1995.nat.dgeo.IGM.LM.quanti

Quantifying the Effects of Changing Deposition Rates and Hiatii on the Stratigraphic Distribution of Fossils - Hohmann, Niklas (2018)
Keywords: Stratigraphy; Paleontology; Statistics; Stratigraphic Paleobiology; Data Processing; Measure Theory; Information Theory

Quantitative Analyse des CO_2_-Gehaltes im Heißmehl der PZ-Klinkerproduktion - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Muck, Michael; Hans-Willhelm, Meyer (14. Internationale Baustofftagung IBAUSIL, 2000)
UnivIS-Import:2015-04-16:Pub.2000.nat.dgeo.IGM.LM.quanti_80

Quantitative analysis of crystal-interface frequencies in granitoids: Implications for modelling of parent-rock texture and its influence on the properties of plutoniclastic sands - Weltje, Gert Jan; Paredis, Bram; Caracciolo, Luca; Heins, William (Sedimentary Geology, 2018)
Generation of sediments from crystalline rocks is the result of a complex and incompletely understood suite of processes. The time evolution of the rock-fragment assemblage in sands derived from granitoids is determined by the relative strengths of crystal interfaces and their abundances in the parent rock. In this study we highlight the role of crystal-interface frequencies in granitoids. Strong evidence for non-random texture with significant implications for predicted interface frequencies have been reported in previous studies. We analysed available interface-frequency data from granitoids using methods of compositional data analysis, and connected our results to existing texture classifications. On average, granitoids display a high degree of ordering with significant depletion of isomineralic interfaces relative to expectations based on random texture. Analysis of 210 normalized interface frequency distributions from nine different granitoids reveals a consistent pattern of variation among interface frequencies, which suggests a single underlying petrogenetic process related to the combined effects of nucleation and textural equilibration ("coarsening").In view of the large scatter of relative interface frequencies within and among granitoids, we propose to model their distribution empirically for the purpose of calibrating sediment-generation studies. Multivariate normal distributions of centred log-ratio transformed relative frequencies are capable of capturing ∼95% of the observed variability with a limited number of dimensions. As a rule of thumb, the number of dimensions needed to approximate interface-frequency counts can be taken equal to the number of mineral classes, which is (much) smaller than the number of interface classes. Mathematical analysis shows that the joint variability of rock texture and composition may be factorized into three statistically independent measures: modal composition, crystal-size probability density functions, and normalized interface frequencies. The potential independence of these measures permits objective identification of petrogenetically significant correlations among them, which will be indicated by statistically significant cross-covariances. At this stage, inferences from microscopic texture analysis cannot be extrapolated to the scale of entire drainage basins in which sediments are generated, because insufficient data are available on the large-scale spatial heterogeneity of texture and composition of granitoid parent rocks<br

Quantitative analysis of crystalline and amorphous phases in glass-ceramic composites like LTCC by the rietveld method - Kemethmüller, Stefan; Roosen, Andreas; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Journal of the American Ceramic Society, 2006)
Glass-ceramic composites like low-temperature cofired ceramics are densified at temperatures below 900°C via liquid-phase sintering. For high-frequency applications, materials with low dielectric losses are needed. At these frequencies glass exhibits higher dielectric losses than a crystalline phase; therefore, the glass amount is reduced after densification by crystallization. To perform a quantitative X-ray analysis of such glass-ceramic composites, a method based on Rietveld refinement was developed. For optimum results, the X-ray diffraction patterns were fitted using the software TOPAS 2.1 from Bruker AXS. With this method, it is possible to determine quantitatively the amount of crystalline phases and also the amount of the remaining amorphous phase. © 2006 The American Ceramic Society.
UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.LM.quanti

Quantitative analysis of CSH in hydrating alite pastes by in-situ XRD - Bergold, Sebastian; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2013)
In this study about the early hydration of monoclinic alite, a method is presented that allows to follow the formation of the Calcium-Silicate-Hydrates directly and quantitatively over time. The combination of the PONKCS method [20] and the G-factor method [6] allowed the refinement and calibration of a C-S-H phase model which can be used for direct quantification of C-S-H in cementitious pastes. The comparison between the heat flow measured by calorimetry and the heat flow calculated from the phase development of C-S-H revealed that C-S-H formation starts later than is indicated by the measured heat flow. It is therefore assumed that the silicate reaction proceeds the following way: A not XRD-detectable C-S-H phase is precipitated which then evolves into a long-range ordered, XRD-detectable C-S-H. This C-S-H acts as a nucleation site for further long-range ordered C-S-H and leads to the acceleration of alite dissolution and direct formation of C-S-H. © 2013 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LM.quanti
Keywords: Ca; Calcium-silicate-hydrates (C-S-H); Calorimetry (A); Hydration (A); X-ray diffraction (B)

Quantitative analysis of suture lines in Carboniferous ammonoids - Wegerer, Michael; de Baets, Kenneth; Korn, Dieter (FOSSIL RECORD, 2018)
Two morphometric methods are applied and compared for the analysis of suture lines in Early Carboniferous ammonoids of the superfamilies Pericycloidea, Girtyoceratoidea and Goniatitoidea. We analysed (1) classic metric data (proportions of the width and depths or heights of lobes and saddles) using multivariate statistic methods and (2) outline data of the external lobe and the ventrolateral saddle of the same ammonoid taxa using the elliptic Fourier analysis. Both methods lead to similar results and simultaneously demonstrate ontogenetic and phylogenetic trends of these ammonoids. Our results are consistent with three previously suggested evolutionary patterns: (1) a general decrease of the amplitude of lobes and saddles, (2) a proportional widening of the external lobe and (3) a heightening of the median saddl

QUANTITATIVE ANALYSIS OF THE STRENGTH GENERATING C-S-H-PHASE IN CONCRETE BY IR-SPECTROSCOPY - Schmidt-Döhl, Frank Michael; Schulenberg, David; Tralow, Franziska; Neubauer, Jürgen; Wolf, Julian; Ectors, Dominique (Acta Polytechnica CTU Proceedings, 2022)
The C-S-H-phase is the most important strength generating phase in concrete and other cementitious materials. The analysis of C-S-H is therefore an important instrument of innovations in the field of concrete and its durability and sustainability. The quantification and insights in C-S-H are hindered by the predominantly amorphous structure of C-S-H. Only the time consuming and expensive solid state nuclear magnetic resonance spectroscopy (NMR) gives a chance to get results, but is restricted to model substances. A new technique, based on the cheap and widespread infrared-spectroscopy (IR) was developed. The quantitative analysis is based on the silicon content in the different structural units of C-S-H and a calibration with natural and synthetic materials with known silicon content in these units. The technique allows to investigate specimens from real structures. Specimens with quartz or limestone aggregate can be analyzed directly. In other cases the aggregates must be separated, for example with heavy liquid separation. Tests with different mortars showed a good correspondence of measured and expected values of C-S-H concentration.
CRIS-Team Scopus Importer:2022-09-02
Keywords: Calcium-Silicate-Hydrate (C-S-H); quantitative analysis; spectroscopy

Quantitative biochronology of Devonian ammonoids from Morocco and proposals for a refined unitary association method - Monnet, Claude; Klug, Christian; Goudemand, Nicolas; de Baets, Kenneth; Bucher, Hugo (Lethaia, 2011)
Based on a rich dataset, the biostratigraphy of the late Emsian and the Eifelian (Early-Middle Devonian) ammonoids from the Moroccan Tafilalt is re-evaluated. We processed this dataset (comprising 53 species from 15 sections) with the unitary association method (UAM), by means of the UA-graph freeware. This led to the construction of a sequence of 17 UAs (maximal sets of actually or virtually coexisting taxa), which are grouped into 10 laterally reproducible association zones. This biostratigraphical subdivision of this interval is in some parts finer than the classically used empirical stratigraphical scheme and than a previous graphic correlation analysis. It enabled us to measure regional ammonoid diversity of this interval in detail. The UAM is a powerful biochronological method, which benefits from complementary tools to analyse conflicting intertaxon stratigraphical relationships inherent to complex biostratigraphical datasets. In cases of under-constrained superpositional relationships between the taxa, the UAM can yield results, which are not parsimonious in terms of reconstructed virtual coexistences. We suggest several additions to complement the algorithmic steps of the method. The most important is the exhaustive or heuristic reconstruction of possible solutions resolving the observed biostratigraphical contradictions (conflicting inter-taxon superpositional relationships and cycles between maximal cliques) and the selection among the solutions of the most-parsimonious one(s) in terms of reconstructed virtual coexistences. Multiple equivalent results may then be processed with standard consensus techniques. Finally, the robustness of the results can be tested by bootstrapping methods to provide confidence estimates on the ranges and associations of studied taxa.
Keywords: Ammonites; Anti-Atlas; biostratigraphy; correlation; zonation; diversity

Quantitative determination of anhydrite III from dehydrated gypsum by XRD - Seufert, Sebastian; Hesse, Christoph; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2009)
Technical OPC contains mixed sulfate carriers in varying amounts. Gypsum and anhydrite are added to the clinker during the milling process where the gypsum dehydrates partially to bassanite and anhydrite. Due to different hydration kinetics of these phases, it is crucial to be able to characterize the composition of sulfate in a cement system to reach an optimal and reproducible cement hydration. In the current paper different calcium sulfate compositions are investigated by XRD methods in order to identify phase content. Special focus is put on the discrimination of the hemihydrate (bassanite) and anhydrite III as well as on transformation processes of anhydrite III through ambient humidity. © 2009 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.quanti
Keywords: Calcium sulfate; Hydration; Portland cement; X-ray diffraction characterization

Quantitative determination of the decarbonation degree in hot meal of OPC Production by XRD - Muck, Michael; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hans-Willhelm, Meyer (1999)
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LM.quanti_7

Quantitative Fracture Set Characterization. - Drews, Michael; Deckert, Hagen; et al. (Geotectonic Research 96/01 – Special Issue TSK 13 Abstracts, 2010)

Quantitative in-situ X-ray diffraction analysis of early hydration of Portland cement at defined temperatures - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hesse, Christoph; Gäberlein, Peter; Bräu, Michael (Powder Diffraction, 2009)
Investigation into the early hydration of Portland cement was performed by in situ X-ray diffraction (XRD). Technical white cement was used for the XRD analysis on a D5000 diffractometer (Siemens). All diffraction patterns of the in situ measurement which were recorded up to 22 h of hydration at defined temperatures were analyzed by Rietveld refinement. The resulting phase composition was transformed with respect to free water and C-S-H leading to the total composition of the cement paste. The hydration reactions can be observed by dissolution of clinker phases as well as by the formation of the hydrate phases ettringite and portlandite. With increasing temperatures the reactions proceed faster. The formation of ettringite is directly influenced by the rate of dissolution of anhydrite and tricalcium aluminate (C3 A). The beginning of the main period of hydration is marked by the start of portlandite formation. The experiments point out that a quantitative phase analysis of the cement hydration is feasible with standard laboratory diffractometers. © 2009 International Centre for Diffraction Data.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.quanti_9
Keywords: Cement; Hydration; In situ XRD; Rietveld analysis

Quantitative Relationship between Low-Field AMS and Phyllosilicate Fabric: A Review - de Wall, Helga; et al. (Physics and Chemistry of the Earth, 1997)
UnivIS-Import:2015-03-05:Pub.1997.nat.dgeo.IGM.c3tekt.quanti

Quantitative Röntgenbeugungsanalyse an Portlandzementklinkern mit Hilfe der Rietveld Methode - Neubauer, Jürgen; Sieber, Roland (European Journal of Mineralogy, 1996)
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LM.quanti

Quantitative Röntgenbeugungsanalyse zur Prozessoptimierung bei der Portlandzementproduktion - Neubauer, Jürgen (European Journal of Mineralogy, 2000)
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LM.quanti_0

Quantitative röntgenographische Bestimmung des Entsäuerungsgrades im Portlandzement-Heißmehl - Muck, Michael; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Hans-Willhelm, Meyer (2000)
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LM.quanti

Quantitative röntgenographische Phasenanalyse an Portlandzementklinkern - Grundlagen und Anwendung - Neubauer, Jürgen (1999)
UnivIS-Import:2016-07-26:Pub.1999.nat.dgeo.IGM.LM.quanti_20

Quartz pseudomorphs after coesite in eclogites from the Saxonian Erzgebirge - Schmädicke, Esther (European Journal of Mineralogy, 1991)

Radiogenic heat production of Variscan granites from the Western Bohemian Massif, Germany - Scharfenberg, Lars; Regelous, Anette; de Wall, Helga (Journal of Geosciences, 2019)
Much of the Mid-European basement has been consolidated during the Variscan Orogeny and includes large volumes of granitic intrusions. Gamma radiation spectroscopic measurements in three study areas along the western margin of the Bohemian Massif give a record of radiogenic element concentrations in the Variscan granites. Most intrusions of the Fichtelgebirge (except for the Tin Granite) and intrusive complexes in the Bavarian Forest show Th/U ratios exceeding unity, most likely related to abundance of monazite. In contrast, some of the Oberpfalz granites located near the Saxothuringian-Moldanubian boundary (FlossenbUrg, Steinwald and Friedenfels types) are characterized by higher uranium concentrations and thus Th/U < 1. The low Th/U ratios here are in agreement with a possible U mobilisation along the Saxothuringian-Moldanubian contact zone observed in previous studies. Heat production rates of granites in the three study areas vary between 3.9 and 8.9 mu W/m(3), with a mean of 4.9 mu W/m(3). This classifies the intrusions as moderate- to high-heat-producing granites. Considering the huge volume of granitic bodies in the Variscan crust of the Bohemian Massif, the contribution of in situ radiogenic heat production had to have a major impact and should be considered in further thermal modeling.
CRIS-Team WoS Importer:2020-02-28

Radiolarian biodiversity dynamics through the Triassic and Jurassic: implications for proximate causes of the end-Triassic mass extinction - Kocsis, Ádám; Kießling, Wolfgang; Palfy, Jozsef (Paleobiology, 2014)
Within a 60-Myr interval in the Late Triassic to Early Jurassic, a major mass extinction took place at the end of Triassic, and several biotic and environmental events of lesser magnitude have been recognized. Climate warming, ocean acidification, and a biocalcification crisis figure prominently in scenarios for the end-Triassic event and have been also suggested for the early Toarcian. Radiolarians, as the most abundant silica-secreting marine microfossils of the time, provide a control group against marine calcareous taxa in testing selectivity and responses to changing environmental parameters. We analyzed the origination and extinction rates of radiolarians, using data from the Paleobiology Database and employing sampling standardization, the recently developed gap-filler equations and an improved stratigraphic resolution at the substage level. The major end-Triassic event is well-supported by a late Rhaetian peak in extinction rates. Because calcifying and siliceous organisms appear similarly affected, we consider global warming a more likely proximate trigger of the extinctions than ocean acidification. The previously reported smaller events of radiolarian turnover fail to register above background levels in our analyses. The apparent early Norian extinction peak is not significant compared to the long-term trajectory, and is probably a sampling artifact. The Toarcian Oceanic Anoxic Event, previously also thought to have caused a significant radiolarian turnover, did not significantly affect the group. Radiolarian diversity history appears unique and complexly forced, as its trajectory parallels major calcareous fossil groups at some events and deviates at other

Radiolarian biodiversity dynamics through the Triassic and Jurassic: implications for proximate causes of the end-Triassic mass extinction - Kocsis, Adam T.; Kießling, Wolfgang; Palfy, Jozsef (Paleobiology, 2014)
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LP.radiol

Radiolarian diversity patterns in the latest Jurassic-earliest Cretaceous - Kießling, Wolfgang (Palaeogeography, Palaeoclimatology, Palaeoecology, 2002)
The global diversity patterns of latest Jurassic-earliest Cretaceous (Tithonian-Berriasian) radiolarian faunas were analyzed based on samples from the European Alps, Oman, Philippines and Antarctica and an extensive literature survey. Several measures of diversity were applied to faunas from tropical (Oman, Mexico, Pacific), subtropical (Alps, California, Philippines, Japan), and subpolar (Antarctic Peninsula, New Zealand, Northern Russia) localities. Original diversity patterns are obscured by taxonomic, sedimentological, and preservational biases. Qualitative and quantitative corrections of these biases indicated a significant diversity gradient from tropical-subtropical to subpolar latitudes, but no significant difference between tropical and subtropical assemblages. The latitudinal diversity gradient was apparently asymmetrical, being steeper in the Northern Hemisphere than in the Southern Hemisphere. In the Southern Hemisphere the diversity gradient was similar to the one observed in modern radiolarian sedimentary assemblages. Considering the more equable climate of the Tithonian-Berriasian, it appears unlikely that temperature was the only control of the observed diversity patterns. The results substantiate the notion of latitudinal diversity gradients as a time-invariant feature of the Earth, possibly driven by gradients in biome size. © 2002 Elsevier Science B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LP.radiol
Keywords: Biodiversity; Cretaceous; Jurassic; Paleogeography; Radiolarians

Radiolarian faunal characteristics in Oligocene sediments of the Kerguelen Plateau, Leg 183, Site 1138 - Kießling, Wolfgang; et al. (Proceedings of the Ocean Drilling Program: Scientific Results, 2002)
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LP.radiol_7

Ramp morphology controlling the facies differentiation of a Late Ordovician reef complex at Bachu, Tarim Block, NW China - Zhang, Yuandong; Munnecke, Axel; Wang, Jianpo; Lin, Yue (Lethaia, 2015)
A carbonate ramp in the shallow-marine northwestern part of the Central Tarim Uplift, Bachu, NW China, exhibits an extraordinary Late Ordovician reef complex along the Lianglitag Mountains, exposed for a distance of about 25 km. Seven localities within the 'Middle Red Limestone' of the Upper Member of the Lianglitag Formation (Katian, Late Ordovician) illustrated the changes in biofacies and lithofacies: northern, seaward-directed patch reefs are replaced towards the south by coeval grain banks. The patch reef units are dominated by microbial and calcareous algal components. The reefs at the northernmost locality are knoll-shaped, kalyptra-shaped or irregularly shaped with sizes of individual reefs increasing from about 2 m in height and diameter. Stratigraphically upward, reefs notably expand to larger structures by several mounds coalescing; they are generally about 10 m thick and tens of metres in lateral extent. The maximum thickness of the main patch reef is more than 30 m, and its diameter is around 100 m. The reefal units turn into biostromes with gentler relief southward and still further south grade into banks composed of peloids and coated grains. The southernmost locality is still a shallow-water bank, and the coastline is not documented in the study area. The present evidence indicates that the Late Ordovician palaeo-oceanography provided a number of environments for the optimal growth of carbonate build-ups; microbial-calcareous algal communities could thrive in areas where the innovative metazoan reef frameworks consisting of corals and stromatoporoids did not play a significant role. The ramp morphology, especially changes in water depth, controlled the configuration of the reef complex.
Keywords: Bachu; Late Ordovician; Lianglitag Formation; NW China; Reef complex; Tarim Block

Rapid groundwater recharge dynamics determined from hydrogeochemical and isotope data in a small permafrost watershed near Umiujaq (Nunavik, Canada) - Cochand, M.; Molson, J.; Barth, Johannes; van Geldern, Robert; Lemieux, J-M; Fortier, R.; Therrien, R. (Hydrogeology Journal, 2020)
Hydrogeochemical data are used to better understand recharge dynamics and to support a hydrogeological conceptual model in a 2-km2 watershed in a discontinuous permafrost zone in Nunavik, Canada. The watershed contains an upper (surficial) and lower aquifer within Quaternary deposits, above and below a marine silt layer containing ice-rich permafrost mounds. The analysis is based on water samples from precipitation, groundwater monitoring wells, ground ice in permafrost mounds, thermokarst lakes and a perennial stream. Groundwater geochemistry in both aquifers reflects young, poorly evolved waters, with mainly Ca-HCO3 water types and low mineralisation ranging from 11 to 158 mg/L total dissolved solids (TDS), implying short pathways and rapid travel times of a year or less. While relatively low, TDS signatures in groundwater and surface water show increasing values downgradient. Groundwater isotope values (δ18OH2O and δ2HH2O) are often strongly influenced by snowmelt, while those of thermokarst lakes show evidence of evaporation. Recharge along the cuesta contributes to a transverse component of groundwater flow within the valley with higher TDS and δ13CDIC values influenced by open-system weathering. Even where permafrost-free, the marine silt unit has a strong confining effect and plays a more important role on recharge dynamics than the discontinuous permafrost. Nevertheless, the vulnerability of these types of hydrogeological aquifer systems is expected to increase due to rapid recharge dynamics associated with the gradual loss of the confining effect of permafrost. This hydrogeochemical data set will be useful as a baseline to document impacts of permafrost degradation on the hydrogeological system.
CRIS-Team Scopus Importer:2020-02-04
Keywords: Canada; Cold regions hydrogeology; Hydrochemistry; Natural isotope tracers; Permafrost

Rare peak and ubiquitous post-peak zircon in eclogite: Constraints for the timing of UHP and HP metamorphism in Erzgebirge, Germany - Schmädicke, Esther; Will, Thomas M.; Ling, Xiaoxiao; Li, Xian-Hua; Li, Qiu-Li (Lithos, 2018)
Keywords: Erzgebirge; Exhumation; Eclogite; UHP metamorphism; Symplectite; U-Pb dating

Rate of E–W extension in the Volcanic Tableland, California (USA): A comparison of strain rates on two different timescales - Salomon, Eric (Geosphere, 2023)
The Eastern California shear zone (USA) is a broad zone of transtensional deformation related to the relative motion between the Pacific and North American plates. Due to its active deformation and seismicity, the zone receives great attention, with specific focus on slip rates of major active faults. To contribute to a better understanding of the long-term strain accumulation in this zone, this study quantifies the long-term E–W-directed extensional strain rate based on the analysis of N–S-trending normal fault scarps in the 765-k.y.-old Bishop tuff (Volcanic Tableland). The average extensional strain rate determined over the past 765 k.y. is 0.29 ± 0.10 mm/yr per 10 km (29 ± 10 nanostrain/yr) and similar to the current rate of elastic strain accumulation rate in the Volcanic Tableland (0.30 ± 0.13 mm/yr per 10 km; 30 ± 13 nanostrain/yr) determined by Global Positioning System (GPS) data. The present-day E–W strain rate across the entire Eastern California shear zone at the latitude of the Volcanic Tableland is 0.36 ± 0.05 mm/yr per 10 km (36 ± 5 nanostrain/yr). This suggests that the local rate of E–W extension has not changed significantly since the mid-Pleistocene. Furthermore, if the Volcanic Tableland is representative of the greater region, as the GPS data suggest, this would also indicate a constant extension rate across the Eastern California shear zone at the latitude of 37.5°N over the 765 k.y. time period. These results suggest that late Pleistocene and Holocene extension rates of major faults in this zone can be interpreted in light of a presumably unchanged far-field stress system since at least the mid-Pleistocene. <br

Reaction kinetics during early hydration of calcined phyllosilicates in clinker-free model systems - Scherb, Sebastian; Maier, Matthias; Beuntner, Nancy; Thienel, Karl Christian; Neubauer, Jürgen (Cement and Concrete Research, 2021)
Keywords: Supplementary cementitious material; Thermogravimetry; In situ X-ray diffraction; Reaction kinetics; Calorimetry; Calcined clay

Reaction kinetics of dual setting α-tricalcium phosphate cements - Hurle, Katrin; Christel, Theresa; Gbureck, Uwe; Moseke, Claus; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (Journal of Materials Science: Materials in Medicine, 2016)
Addition of ductile polymers to calcium-deficient hydroxyapatite (CDHA)—forming bone cements based on α-tricalcium phosphate (α-TCP) is a promising approach to improve the mechanical performance of α-TCP cements and extend their application to load-bearing defects, which is else impeded by the brittleness of the hardened cement. One suitable polymer is poly-(2-hydroxyethylmethacrylate) (p-HEMA), which forms during cement setting by radical polymerisation of the monomer. In this study the hydration kinetics and the mechanical performance of α-TCP cements modified with addition of different HEMA concentrations (0–50 wt% in the cement liquid) was investigated by quantitative in situ XRD and four-point bending tests. Morphology of CDHA crystals was monitored by scanning electron microscopy. The hydration of α-TCP to CDHA was increasingly impeded and the visible crystal size of CDHA increasingly reduced with increasing HEMA concentration. Modification of the cements by adding 50 wt% HEMA to the cement liquid changed the brittle performance of the hardened cement to a pseudoplastic behaviour, reduced the flexural modulus and increased the work of fracture, while lower HEMA concentrations had no significant effect on these parameters. In such a composite, the extent of CDHA formation was considerably reduced (34.0 ± 1.8 wt% CDHA with 50 % HEMA compared to 54.1 ± 2.4 wt% CDHA in the reference formed after 48 h), while the general reaction kinetics were not changed. In conclusion, while the extent of CDHA formation was decreased, the mechanical properties were noticeably improved by addition of HEMA. Hence, α-TCP/HEMA composites might be suitable for application in some load-bearing defects and have adequate properties for mechanical treatment after implantation, like insertion of screws.
Keywords: Association reactions; Bearings (machine parts); Bending tests; Bone cement; Brittle fracture; Defects; Fracture; Fracture mechanics; Free radical reactions; Hardening; Hydration; Kinetics; Polymers; Scanning electron microscopy; Setting; Shear thinning 2-hydroxyethylmethacrylate; Calcium deficient hydroxyapatite; Four-point bending test; Hydration kinetics; Mechanical performance; Mechanical treatments; Tri-calcium phosphates; Tricalcium phosphate cement

Reactivity of metakaolin in alkaline environment: Correlation of results from dissolution experiments with XRD quantifications - Scherb, Sebastian; Köberl, Mathias; Beuntner, Nancy; Thienel, Karl Christian; Neubauer, Jürgen (Materials, 2020)
Systematic investigation of filtrates and filter residues resulting from a 24 h treatment of metakaolin in different alkaline solutions were performed. On filtered metakaolin particles, inductively coupled plasma-optical emission spectrometry (ICP-OES) measurements reveal an enrichment of iron and titanium, which suggests an inhomogeneous distribution of these cations. Since the SiO2/Al2O3 ratio remains constant in all filter residues examined, the dissolution of the Si and Al monomers is congruent. Structural differences, identified by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) as a consequence of alkali uptake, influence the X-ray scattering contribution of metakaolin, and thus quantifications with the partial or no known crystal structure (PONKCS) method. This leads to deviations between the degree of reaction calculated from Si and Al solubility from filtrate and that quantified by quantitative powder X-ray diffraction (QPXRD) using the filter residue. Nevertheless, the described changes do not cause a shift in the X-ray amorphous hump in case of congruent dissolution, and thus allow the quantification of the metakaolin before and after dissolution with the same hkl-phase model.
CRIS-Team Scopus Importer:2020-06-05
Keywords: Alkaline solution; Calcined clay; Degree of reaction; Metakaolin; PONKCS; Supplementary cementitious material

Reading traces of the past - the Burghöhle Wolfsegg as meeting place for humans, cave lions and co. Spurenlesen in der Vergangenheit - die Burghohle Wolfsegg als Treffpunkt fur Mensch, Hohlenlowe und Co. - Hilpert, Brigitte (Mitteilungen - Verbandes der Deutschen Hohlen- und Karstforscher, 2023)
On the occasion of a tour into the "Burghohle Wolfsegg" in the Franconian Alb (Bavaria), the castle complex was also visited. The faunal remains found there originate from various sites in the cave and are described for the first time. A faunal complex was excavated from the Barenkeller in 1985. The fauna determined here with brown bear (Ursus arctos), cave bear (Ursus spelaeus), cave lion (Panthera leo spelaea) as well as some herbivores can be placed in a rather cool to cold climatic phase of the late Pleistocene around 60,000 - 20,000 years BP. Of particular note is an upper arm bone of a cave lion on which cut marks were found. This is the first such evidence for a cave in the Franconian Alb. Some cut and impact marks on other bones also prove the presence of humans and their impact on animal carcasses or hunted prey. All the material shows traces of various transport phases that led via a former cave room and a shaft step to its current site. At the Rittersaal site, finds were recovered in the 1980s and 1990s. The fauna consists of various domestic animals such as cattle, pigs, sheep/goats, horses and dogs. Wild animals such as red deer (Cervus elaphus) and some predators also occur. Accompanying finds such as pottery shards, a barrel stopper and other human remains prove that the finds can be considered as kitchen waste of the Middle Ages and more recent periods. In 2018, further finds were recovered during the removal of a pile of earth on the wall of the castle building, which are likely to date from the 15th - 17th centuries. In addition to pottery sherds, the find complex consists of fragmented bones of cattle, pig, sheep/goat and horse, with evidence of red deer alongside. Traces of the cutting of the carcasses suggest an interpretation as kitchen waste.
CRIS-Team Scopus Importer:2023-09-22

Rebuilding biodiversity of Patagonian marine molluscs after the end-Cretaceous mass extinction - Aberhan, Martin; Kießling, Wolfgang (PLoS ONE, 2014)
We analysed field-collected quantitative data of benthic marine molluscs across the Cretaceous-Palaeogene boundary in Patagonia to identify patterns and processes of biodiversity reconstruction after the end-Cretaceous mass extinction. We contrast diversity dynamics from nearshore environments with those from offshore environments. In both settings, Early Palaeogene (Danian) assemblages are strongly dominated by surviving lineages, many of which changed their relative abundance from being rare before the extinction event to becoming the new dominant forms. Only a few of the species in the Danian assemblages were newly evolved. In offshore environments, however, two newly evolved Danian bivalve species attained ecological dominance by replacing two ecologically equivalent species that disappeared at the end of the Cretaceous. In both settings, the total number of Danian genera at a locality remained below the total number of late Cretaceous (Maastrichtian) genera at that locality. We suggest that biotic interactions, in particular incumbency effects, suppressed post-extinction diversity and prevented the compensation of diversity loss by originating and invading taxa. Contrary to the total number of genera at localities, diversity at the level of individual fossiliferous horizons before and after the boundary is indistinguishable in offshore environments. This indicates an evolutionary rapid rebound to pre-extinction values within less than ca 0.5 million years. In nearshore environments, by contrast, diversity of fossiliferous horizons was reduced in the Danian, and this lowered diversity lasted for the entire studied post-extinction interval. In this heterogeneous environment, low connectivity among populations may have retarded the recolonisation of nearshore habitats by survivors. © 2014 Aberhan, Kiessling.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LP.rebuil

Recent advances in heteromorph ammonoid palaeobiology - Hoffmann, René; Slattery, Joshua S.; Kruta, Isabelle; Linzmeier, Benjamin J.; Lemanis, Robert E.; Mironenko, Aleksandr; Goolaerts, Stijn; de Baets, Kenneth; Peterman, David J.; Klug, Christian (Biological Reviews, 2021)
Heteromorphs are ammonoids forming a conch with detached whorls (open coiling) or non-planispiral coiling. Such aberrant forms appeared convergently four times within this extinct group of cephalopods. Since Wiedmann's seminal paper in this journal, the palaeobiology of heteromorphs has advanced substantially. Combining direct evidence from their fossil record, indirect insights from phylogenetic bracketing, and physical as well as virtual models, we reach an improved understanding of heteromorph ammonoid palaeobiology. Their anatomy, buoyancy, locomotion, predators, diet, palaeoecology, and extinction are discussed. Based on phylogenetic bracketing with nautiloids and coleoids, heteromorphs like other ammonoids had 10 arms, a well-developed brain, lens eyes, a buccal mass with a radula and a smaller upper as well as a larger lower jaw, and ammonia in their soft tissue. Heteromorphs likely lacked arm suckers, hooks, tentacles, a hood, and an ink sac. All Cretaceous heteromorphs share an aptychus-type lower jaw with a lamellar calcitic covering. Differences in radular tooth morphology and size in heteromorphs suggest a microphagous diet. Stomach contents of heteromorphs comprise planktic crustaceans, gastropods, and crinoids, suggesting a zooplanktic diet. Forms with a U-shaped body chamber (ancylocone) are regarded as suspension feeders, whereas orthoconic forms additionally might have consumed benthic prey. Heteromorphs could achieve near-neutral buoyancy regardless of conch shape or ontogeny. Orthoconic heteromorphs likely had a vertical orientation, whereas ancylocone heteromorphs had a near-horizontal aperture pointing upwards. Heteromorphs with a U-shaped body chamber are more stable hydrodynamically than modern Nautilus and were unable substantially to modify their orientation by active locomotion, i.e. they had no or limited access to benthic prey at adulthood. Pathologies reported for heteromorphs were likely inflicted by crustaceans, fish, marine reptiles, and other cephalopods. Pathologies on Ptychoceras corroborates an external shell and rejects the endocochleate hypothesis. Devonian, Triassic, and Jurassic heteromorphs had a preference for deep-subtidal to offshore facies but are rare in shallow-subtidal, slope, and bathyal facies. Early Cretaceous heteromorphs preferred deep-subtidal to bathyal facies. Late Cretaceous heteromorphs are common in shallow-subtidal to offshore facies. Oxygen isotope data suggest rapid growth and a demersal habitat for adult Discoscaphites and Baculites. A benthic embryonic stage, planktic hatchlings, and a habitat change after one whorl is proposed for Hoploscaphites. Carbon isotope data indicate that some Baculites lived throughout their lives at cold seeps. Adaptation to a planktic life habit potentially drove selection towards smaller hatchlings, implying high fecundity and an ecological role of the hatchlings as micro- and mesoplankton. The Chicxulub impact at the Cretaceous/Paleogene (K/Pg) boundary 66 million years ago is the likely trigger for the extinction of ammonoids. Ammonoids likely persisted after this event for 40–500 thousand years and are exclusively represented by heteromorphs. The ammonoid extinction is linked to their small hatchling sizes, planktotrophic diets, and higher metabolic rates than in nautilids, which survived the K/Pg mass extinction event.
CRIS-Team Scopus Importer:2021-01-22
Keywords: anatomy; cephalopods; facies distribution; geochemistry; heteromorph ammonoids; palaeobiology

Recharge velocity and geochemical evolution for the Permo-Triassic Sherwood Sandstone, Northern Ireland - Barth, Johannes; et al. (Journal of Hydrology, 2005)

Recharging Mechanisms and Seawater Intrusion in Karst Aquifers in Northwest Sri Lanka, Based on Hydrogeochemistry and Water Isotopes - Bandara, U. G. Chaminda; Diyabalanage, Saranga; Barth, Johannes; Chandrajith, Rohana (ACS ES&T Water, 2023)
Geochemical and isotope data of karstic aquifer systems in the Mulankavil area in northwest Sri Lanka were investigated to constrain recharging and discharging mechanisms, and possible seawater intrusions. The electrical conductivity (EC) of groundwater was measured in the dry (n = 139) and rainy (n = 78) seasons to assess possible saltwater intrusions, from which 25 wells were selected for detailed geochemical analyses. Water isotope analyses (expressed as delta 2HH2O, delta 18OH2O) were measured in 32 wells for five months. The mean EC of groundwater during both seasons was 2,435 mu S/cm, and higher values from the coastal stretch indicated seawater intrusion. Increasing EC values in the dry period indicated a temporary inland saltwater wedge. High hydraulic gradients with rapidly discharging groundwater partially removed seawater intrusions during the monsoon season. Water isotopes in the region defined an individual evaporation line with delta 2HH2O= 6.69*delta 18OH2O -0.77 (r2 = 0.989), indicating a long enough residence time to allow evaporation before infiltration. Groundwater near sinkhole systems was found to be predominantly of the Ca-Mg-HCO3 type and changes to the Na-Cl type toward the coast. The results of this study revealed conduit systems in the karst subsurface as essential pathways for controlling seawater intrusion.
CRIS-Team WoS Importer:2023-03-10

Recognition of drilling-induced remanent magnetization by Q-factor analysis: A case study from the KTB-Drillholes - de Wall, Helga; et al. (Journal of Applied Geophysics, 2001)
Keywords: Drill cores; German Continental Deep Drilling Program; Koenigsberger ratio; Secondary magnetization

Recognition of the Boda event in the Pin Formation of northern India based on new d13C and conodont data. - Buggisch, Werner; Lehnert, Oliver; Joachimski, Michael; et al. (Acta Palaeontologica Sinica, 2007)
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LG.recogn

Reconstructing Depositional Rates and Their Effect on Paleoenvironmental Proxies: The Case of the Lau Carbon Isotope Excursion in Gotland, Sweden - Jarochowska, Emilia; Nohl, Theresa; Grohganz, Madleen; Hohmann, Niklas; Vandenbroucke, Thijs; Munnecke, Axel (Paleoceanography and Paleoclimatology, 2020)
Variations in depositional rates affect the temporal depositional resolutions of proxies used for paleoenvironmental reconstructions; for example, condensation can make reconstructed environmental changes appear very abrupt. This is commonly addressed by transforming proxy data using age models, but this approach is limited to situations where numerical ages are available or can be reliably inferred by correlation. Here we propose a new solution, in which relative age models are constructed based on proxies for depositional rates. As a case study, we use the onset of the late Silurian Lau Carbon Isotope Excursion (LCIE) in Gotland, Sweden. The studied succession is a gradual record of shallowing upward in a tropical, neritic carbonate platform. As proxies for depositional rates we tested thorium concentration, carbonate content, and the concentration of pelagic palynomorphs. These three proxies were used to create relative age models using the previously published DAIME model. We applied these models to transform the δ13Ccarb values as well as concentrations of selected redox‐sensitive elements. The three relative age models yielded qualitatively similar results. In our case study, variations in depositional rates resulted in peaks of redox proxies appearing up to 76% higher when taken at face value, compared to when accounting for these rates. In the most extreme cases, our corrections resulted in a reversal in the stratigraphic trend of elemental concentrations. This approach can be applied and developed across depositional setting and types of paleoenvironmental proxies. It provides a flexible tool for developing quantitative models to improve our understanding of the stratigraphic record.<br

Reconstructing environmental signals across the Permian-Triassic boundary in the SE Germanic Basin: A Quantitative Provenance Analysis (QPA) approach - Caracciolo, Luca; Ravidà, Domenico; Chew, David; Janßen, Meike; Luensdorf, Keno Nils; Heins, William A.; Stephan, Tobias; Stollhofen, Harald (Global and Planetary Change, 2021)
Global tectonic and climatic models for the Permian-Triassic boundary (PTB) are highly debated. One of the most disputed topics is the temperature increase associated with CO2 emissions generated by the Siberian Trap volcanism and its potential influence on chemical weathering and associated variations in sediment fluxes. By integrating crustal architecture, plate modelling, structural kinematics, and two climatic models, we reconstruct the drainage evolution of Variscan tectonostratigraphic units from the SE portion of the Germanic Basin, from which we also extract the parameters necessary to calculate sediment flux across a time-scale of 28 Ma (Guadalupian-Lower Triassic). We reconstruct the sedimentary response to climatic and tectonic perturbations using Quantitative Provenance Analysis (QPA) and integrate compositional data into a sedimentological framework, paleodrainage and paleoclimatic models. Raman heavy mineral analysis, as well as geochronology and geochemistry of detrital apatite, zircon, and rutile, document variation in drainage lithologies and sediment flux which are controlled by regional extensional tectonics and increasingly humid conditions at the PTB. The sedimentary successions of the SE Germanic Basin record climatic perturbations on a 104 years timescale, while the effects of tectonics are visible on a 106 years timescale. The interplay of climate, tectonics and lithology, and their effects on sediment production and drainage evolution resulted in changes in sediment flux from 2.3 Mt./yr during the Guadalupian (Capitanian), to 3.80 Mt./yr in the Lopingian (Changhsingian) to 7.44 Mt./yr at the end of the Lower Triassic (Olenekian). The multifaceted workflow provided in this study represents the first step towards more precise reconstructions of sediment routing systems in deep-time and provides the first ground-truthed quantification of sediment flux across the Permian-Triassic Boundary.
CRIS-Team Scopus Importer:2021-09-24
Keywords: Tectonic and climatic perturbations; Environmental signals; External forcing controls; Quantitative Provenance Analysis; Permian-Triassic Boundary

Reconstructing environmental signals across the Permian-Triassic boundary in the SE Germanic basin: Paleodrainage modelling and quantification of sediment flux - Ravidà, Domenico; Caracciolo, Luca; Heins, William A.; Stollhofen, Harald (Global and Planetary Change, 2021)
Reconstructing sediment load in deep-time is one of the greatest challenges in the reconstruction of ancient sediment routing systems, particularly because solid statistical models are absent and paleo-climatic, paleo-tectonic, and sedimentary constraints are lacking. This study proposes a reliable workflow for the estimation of paleo-sediment fluxes (Qs) applying the BQART model to a case study from the SE Germanic Basin across the Middle Permian – Early Triassic interval. The input parameters of the simulations derive from: integrated plate modelling and structural kinematics; paleodrainage and paleogeographic reconstructions; global circulation models; and sandstone compositional signatures. We apply Monte Carlo simulation to overcome the input uncertainties for eight different scenarios obtained from the combination of two area estimates, two climate models, and two time resolutions. All the models are in general agreement and show changes in sediment flux (i) being steady or declining slightly through the Middle Permian, (ii) an increase of 31% at the beginning of the Late Permian (3.6–4.6 Mt yr−1), (iii) and a nearly 100% rise at the onset of the Early Triassic (7.4 Mt yr−1). The variation of sediment load across the PTB is coeval to the transition from meandering/sabkha to perennial braided depositional settings recorded from the well data of Obernsees-1 and Lindau-1; it results from both increased tectonism and seasonal precipitation. The Qs estimates agree with those of modern drainages under analogous environmental conditions, highlighting the reliability of the workflow included in this study for the quantification of sediment flux in deep time. Furthermore, the results of this study provide new insights on the highly debated evolution of the continental sequences across the PTB with strong implications for both past and future paleo-environmental reconstructions.
CRIS-Team Scopus Importer:2021-09-17
Keywords: Central European Basin Systems; External forcing controls; Paleodrainage reconstruction; Permo-Triassic boundary; Sediment flux; Sediment routing system

Reconstructing post-Jurassic overburden in central Europe: new insights from mudstone compaction and thermal history analyses of the Franconian Alb, SE Germany - Freitag, Simon; Drews, Michael; Bauer, Wolfgang; Duschl, Florian; Misch, David; Stollhofen, Harald (Solid Earth, 2022)
The Franconian Alb of SE Germany is characterized by large-scale exposures of Jurassic shallow marine limestones and dolostones, which are frequently considered to be outcrop analogues for deep geothermal reservoir rocks in the North Alpine Foreland Basin farther south. However, the burial history of the Franconian Alb Jurassic strata is not well known as they were affected by emersion, leading to extensive erosion and karstification with only remnants of the original Cretaceous and Cenozoic cover rocks preserved. To estimate the original thicknesses of the post-Jurassic overburden we investigated the petrophysical properties and the thermal history of Lower and Middle Jurassic mudstones to constrain their burial history in the Franconian Alb area. We measured mudstone porosities, densities, and maturities of organic material and collected interval velocities from seismic refraction and logging data in shallow mudstone-rich strata. Mudstone porosities and P-wave velocities vertical to bedding were then related to a normal compaction trend that was calibrated on stratigraphic equivalent units in the North Alpine Foreland Basin. Our results suggest maximum burial depths of 900-1700 m, 300-1100 m of which is attributed to Cretaceous and younger sedimentary rocks overlying the Franconian Alb Jurassic units. Compared to previous considerations this implies a more widespread distribution and increased thicknesses of up to similar to 900 m for Cretaceous and up to similar to 200 m for Cenozoic units in SE Germany. Maximum overburden is critical to understand mechanical and diagenetical compaction of the dolostones and limestones of the Upper Jurassic of the Franconian Alb. The results of this study therefore help to better correlate the deep geothermal reservoir properties of the Upper Jurassic from outcrop to reservoir conditions below the North Alpine Foreland Basin. Here, the Upper Jurassic geothermal reservoir can be found at depths of up to 5000 m.
CRIS-Team WoS Importer:2022-07-22

Reconstructing the environmental conditions around the Silurian Ireviken Event using the carbon isotope composition of bulk and palynomorph organic matter - Vandenbroucke, Thijs R.A.; Munnecke, Axel; Leng, Melanie J.; Bickert, Torsten; Hints, Olle; Gelsthorpe, David; Maier, Georg; Servais, Thomas (Geochemistry Geophysics Geosystems, 2013)
The carbon isotope composition (δ13C) of bulk organic matter and two palynomorph groups (scolecodonts and chitinozoans) from the Llandovery-Wenlock strata of Gotland (E Sweden) are compared to gain knowledge about carbon cycling in the Silurian (sub)tropical shelf environment. The δ13C values of the palynomorphs are mostly lower than the δ13C values of the bulk organic matter, and the δ13C values of the benthic scolecodonts are lower than those of the planktonic chitinozoans. While the difference between bulk and palynomorph δ13C may be in part a function of trophic state, the lower values of the scolecodonts relative to those of chitinozoans, which are assumed to live in the well-mixed water column, might imply an infaunal mode of life for the polychaetes that carried the scolecodonts. Lower δ13C for the scolecodonts in the middle of the section may represent variations in primary marine productivity (supported by acritarch abundance data), oxidation of organic matter in the bottom waters, or genera effects. In general, however, trends between the three data sets are parallel, indicating similarities in the low frequency, environmentally forced controls. The δ13C data show a decreasing trend from the base of the section, up to a horizon well below the base of the Upper Visby Formation. At this level, and therefore probably several 10 kyr before the δ13C increase in the carbonates, the δ13C organic values increase by ∼1‰. This perhaps is an expression of a changed composition of the bulk organic matter associated with the extinction events prior to the Llandovery-Wenlock boundary. ©2013. American Geophysical Union. All Rights Reserve
Keywords: bulk organic matter; carbon isotopes; chitinozoans; Gotland; Llandovery-Wenlock; scolecodonts; trophic chain

Reconstructing the Upper Permian sedimentary facies distribution of a tight gas field in Central Europe on the basis of an analog field study in the Panamint Valley, western U.S. - Vackiner, Anna Alexandra; Antrett, Philipp; Strozyk, Frank; Stollhofen, Harald; Back, Stefan; Kukla, Peter (Geosphere, 2012)
Comparison of modern deposits in the Panamint Valley, western United States, to core and geophysical data from a Permian (Rotliegend, Germany) tight gas field allows for improved understanding of the interaction of tectonics and sedimentary processes during Rotliegend deposition. The Panamint Valley was selected for a modern analog of the subsurface Rotliegend Basin because both study sites are characterized by (1) elongated grabens with large-scale bounding fault zones resulting from synsedimentary transtensional tectonics; (2) fault-controlled paleotopography as key controlling parameter for the sediment facies distribution, including alluvial fans, dunes, wet and damp interdune sandflats, and ephemeral dry lake deposits; and (3) local sediment provenance from sedimentary and volcanic rocks. The analysis of satellite images and field data from the Panamint Valley enabled the development of a conceptual model involving topography, synsedimentary faulting, and wind activity as controlling factors for the sediment facies distribution. The application of the model to the reconstructed Rotliegend paleotopography of the German subsurface study site allows for prediction of the facies distribution prior to the Triassic-Cretaceous tectonic overprinting. As a consequence, we expect a sediment facies succession from (1) alluvial fan deposits along the hanging walls of the basin-bounding fault zones to (2) distributary fluvial channel deposits toward the basin center and (3) ephemeral lake deposits in the deepest basin area. (4) Eolian dune accumulation and preservation is mainly concentrated on hanging-wall locations. However, additional dune deposits are proposed above overlapping step faults and on footwalls of synsedimentary active faults. (5) Sandflats occur on the upwind and downwind margins of the dune field. These predictions are calibrated to core and geophysical well log data. © 2012 Geological Society of America.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.recons

Reconstructing time and diagenesis of limestone-marl alternations from the selective compaction of colonies of the tabulate coral Halysites - Nohl, Theresa; Munnecke, Axel (Bulletin of Geosciences, 2019)

Reconstruction of cyclic Mesozoic-Cenozoic stress development in SE Germany using fault-slip and stylolite inversion - Köhler, Saskia; Duschl, Florian; Fazlikhani, Hamed; Köhn, Daniel; Stephan, Tobias; Stollhofen, Harald (Geological Magazine, 2022)
The Franconian Platform of SE Germany and the underlying Permian and Triassic rocks that developed from latest Permian to Triassic time were affected by multiple compressional and extensional events that created a complex fracture, fault and stylolite network. We reconstructed the spatio-temporal variations of post-Triassic palaeostress fields in the Franconian Platform and Triassic strata using fault-slip and tectonic stylolite inversion. Our highly resolved stress inversion enables us to demonstrate a cyclic stress evolution from the stress regime of normal faulting to thrusting, strike-slip and back to normal faulting. Five main stress fields correlating with two stress cycles are determined for Late Jurassic to Cenozoic time. The first cycle consists of: (SF1) an initially NE-SW-directed horizontal extension during Late Jurassic to Early Cretaceous time; (SF2) NNE-SSW-directed horizontal compression with an early set of tectonic stylolites prior to the development of reverse and thrust faults; and (SF3) a strike-slip-dominated setting with (N)NE-(S)SW horizontal compression representing a first relaxation. The second cycle comprises (SF4) NW-SE-directed horizontal extension during Oligocene-Miocene time; and (SF5) a second strike-slip-dominated regime with WNW-ESE to NW-SE horizontal compression during the Alpine shortening, creating the youngest set of tectonic stylolites. In addition, we consider the transitional stages between thrusting and a strike-slip regime as a snapshot in the process of intraplate tectonics.
CRIS-Team WoS Importer:2022-08-26

Reconstruction of Late Bajocian - Bathonian marine palaeoenvironments using carbon and oxygen isotope ratios of calcareous fossils from the Polish Jura Chain (central Poland). - Joachimski, Michael; Wierzbowski, Hubert (Palaeogeography, Palaeoclimatology, Palaeoecology, 2007)
Oxygen and carbon isotope analyses were carried out on Upper Bajocian - Bathonian calcitic belemnite rostra and oyster shells as well as aragonitic ammonite, nautiloid and trigoniid shells from the "Ore-bearing Czeogonekstochowa Clay Formation" in south-central Poland. All samples were studied by means of cathodoluminscence microscopy, trace element, X-ray, and scanning electron microscope (SEM) analysis in order to select best-preserved material. SEM studies allowed classifying some aragonitic ammonite and nautiloid shells (> 99% aragonite) as diagenetically altered. Average δ18O values of oysters, belemnites and trigoniids translate into relatively low palaeotemperatures of 10.1, 9.2 and 7.4 °C, respectively. The comparable δ18O values of bivalves and belemnites indicate that belemnites had a nectobenthic lifestyle and did not record surface water temperatures. The ammonite fauna is interpreted to have been nektonic, however, palaeotemperatures derived from ammonite δ18O (around 18.6 °C) may be overestimated due to a lower, than normal marine, salinity of surface waters. The reduced salinity is inferred as well from sedimentological observations and faunal composition. The obtained δ18O values indicate cool climatic conditions during the Late Bajocian-Bathonian in south-central Poland, which may have been linked with the occurrence of a cold climatic episode. Despite the fact that all studied shells were not precipitated in carbon isotope equilibrium with ambient waters, the δ13C shell values enabled us to roughly estimate isotope composition of dissolved inorganic carbon (DIC) in the Late Bajocian-Bathonian sea of south-central Poland. Water δ13CDIC values calculated from ammonite δ13C are lower in comparison to δ13CDIC values calculated from oyster and belemnite carbon isotope ratios, which in conjunction with ammonite δ18O values indicates lower salinity of surface or shallow near-coastal waters. © 2007 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LG.recons
Keywords: Ammonites; Bajocian; Bathonian; Belemnites; Bivalves; Oxygen and carbon isotopes

Reconstruction of the trophic levels of a fossil fish community from the Late Jurassic Solnhofen Archipelago - Dimitrijevic, Danijela; Ebert, Martin; Kölbl-Ebert, Martina; Munnecke, Axel (EGU 2020, 2020)
Trophic interactions of extinct fishes are central to our understanding of evolution, paleoecology, and their role in the paleo communities, but can be challenging, as these are limited by the incompleteness of the fossil record and by a lack of behavioral data. The extensive fossil record of Actinopterygii comes mostly from Conservation deposits. They provide exceptionally rich information on fossil ecosystems and open outstanding windows into the evolution of life. The best-preserved Late Jurassic actinopterygians are known from the Solnhofen Archipelago, Germany. Despite that the ichthyofauna diversity of the Solnhofen Archipelago has been extensively explored in the last several decades, the dietary preferences of most fish remain unknown or have to be deduced by analogy from dentition and jaw morphology. The aim of this study was to reconstruct the trophic levels of Late Jurassic fish assemblages using Sr / Ca and Ba / Ca measured from phosphatic fish remains, mostly ganoin and cycloid scales recovered from the Ettling locality, which is characterized by exceptionally well-preserved fossil fishes and moderate diagenetic alteration. We classified fish species into four trophic levels (durophagous, lower, middle, and higher trophic level) based on morphology available from the literature. Mean values ​​of Sr, Ca, Ba and their ratios measured by Thermo Scientific iCAP Q inductively coupled plasma mass spectrometer in this study are in accordance with the mean values ​​of previous studies. Differences in values ​​between cleaned and uncleaned samples showed that the cleaning process successfully isolated primary dietary Sr content while dissolving away the diagenetic strontium present in carbonate in the pore spaces. All trophic levels showed low variation of Sr / Ca (0.003 - 0.008 μg / g) and high variation of Ba / Ca values ​​(0.0003 - 0.0014 μg / g). The results showed significant differences between the middle and higher trophic levels (p = 0.03), while durophagous and lower trophic levels fell into the same range of values ​​as the higher trophic level. We demonstrate that the enamel of fossil vertebrates from the Solnhofen Archipelago still contains near-in vivo Sr, Ba, and Ca. The clear distinction between middle and higher trophic levels offers a new functional perspective on the ecological and evolutionary relationships among fishes. However, future studies should not neglect the importance of diagenetic alteration of the samples; proper sample cleaning before measuring isotopic signatures, and careful selection of the analyzed tissue (ie tooth enamel instead of scales or bones due to its resistance to diagenesis).<br

Record of assembly and breakup of Rodinia in the Southwestern Altaids: Evidence from Neoproterozoic magmatism in the Chinese Western Tianshan Orogen - Gao, Jun; Wang, Xin-Shui; Klemd, Reiner; Jiang, Tuo; Qian, Qing; Mu, Li-Xiu; Ma, Yu-Zhou (Journal of Asian Earth Sciences, 2015)
Neoproterozoic gneissic granitoid rocks and a bimodal intrusive complex exposed in the Chinese Western Tianshan Orogen were geochemically and geochronologically studied in order to evaluate the assembly and breakup of Rodinia in the Southwestern Altaids. Zircon U–Pb ages of 903.5 ± 2.2 Ma and 933.6 ± 1.2 Ma were obtained for the Huoshaoqiao and the Wulasutanwutuaiken gneissic granitoid plutons, respectively. Both intrusions have a calcic to calci-alkalic composition and display an enrichment of LREE and LILE and a depletion of HREE and HFSE resembling the geochemical characteristics of Andean arc granites. Their in-situ zircon εHf(t) values of −1.7 to +1.9 and −2.2 to +4.5 further suggest a Late Paleoproterozoic crustal source with limited input of juvenile materials. The Wuwamen bimodal intrusive complex consists of meta-gabbro host rocks and crosscutting granitic dykes. Zircon U–Pb ages of 733 ± 5 Ma and 730 ± 5 Ma were determined for the meta-gabbros and the granitic dykes, respectively. The relative depletion of Nb, Ta and Ti, the Nd isotopic value (εNd(t) = −4.3) of the meta-gabbros, and the Hf isotopic values of gabbroic zircon grains (εHf(t) = +0.4 to +2.8) suggest that the protolithic mafic magma originated from a sub-continental fertilized lithospheric mantle source. Furthermore, the Nd isotopic value (εNd(t) = −11.2) of the granitic dykes and the Hf isotopic values of granitic zircon grains (εHf(t) = −14.3 to −5.6) indicate that the acidic magma originated from lower crustal melting. The dataset presented here in conjunction with previously published data suggest that the ∼900 Ma plutons originated from remelting of older crust in an Andean-type active continental arc setting associated with the assembly of Rodinia, whereas the development of the ∼730 Ma bimodal intrusive magmatism is interpreted as a result of the Rodinia breakup. Thus, the Neoproterozoic magmatism is believed to be a direct consequence of the geodynamic process related to the assembly and breakup of Rodinia in the Southwestern Altaids.<br
Keywords: Altaids; Tianshan; Rodinia; Neoproterozoic magmatism

Record of intermediate-depth subduction seismicity in a dry slab from an exhumed ophiolite - Pennacchioni, G.; Scambelluri, M.; Bestmann, Michel; Notini, L.; Nimis, P.; Plümper, O.; Faccenda, M.; Nestola, F. (Earth and Planetary Science Letters, 2020)
The ophiolitic peridotite and gabbro of Moncuni (Southern Lanzo Massif, Western Alps) retain pre-subduction mantle-to-oceanic, high-temperature (>700C∘) ductile fabrics. These fabrics are overprinted by seismic fracturing and faulting associated with pseudotachylytes. Within the gabbro, the pseudotachylytes preserve dry glass and pristine microlites. The occurrence of rare, minute garnet and the static development of eclogite-facies assemblages in local hydrated domains indicate that pseudotachylytes experienced subduction conditions of 600C∘ and 2.1 GPa. The exceptional survival of glass and the absence of post-oceanic ductile deformation demonstrate prevailing dry conditions during the entire Alpine subduction and exhumation path. Dry conditions inhibited reaction kinetics and viscous flow. In contrast, the majority of the Alpine ophiolites, derived from the upper hydrated portions of the oceanic lithosphere, show pervasive fluid-assisted metamorphism and ductile deformation. The Moncuni body can, therefore, be regarded as representative for the rheological behaviour during subduction of seismic, dry, deeper oceanic lithosphere that is rarely exhumed to the Earth's surface. In Moncuni, the brittle-ductile transition of dry oceanic rocks is constrained to be between 600 and 750C∘. This temperature range corresponds to the observed cut-off of intermediate-depth seismicity within subducting slabs. We infer that the base of the seismic layer corresponds to the brittle-ductile transition of a dry slab rather than the locus of antigorite breakdown triggering earthquakes by dehydration embrittlement.
CRIS-Team Scopus Importer:2020-08-21
Keywords: earthquake; eclogite; fluids; ophiolite; pseudotachylyte; subduction

Recurrence analysis of the mass movement activity at Stambach (Austria) based on radiocarbon dating - Unkel, Ingmar; Ehret, Dominik; Rohn, Joachim (Geomorphology, 2013)
Keywords: Earth flow; Holocene palaeoclimate; Landslide; Northern Calcareous Alps; Radiocarbon dating; Recurrence interval

Red Devonian trilobites with green eyes from Morocco and the silicification of the trilobite exoskeleton - Klug, Christian; Schulz, Hartmut; de Baets, Kenneth (Acta Palaeontologica Polonica, 2009)
Latest Emsian (Early Devonian) sediments at the famous mud-mound- and trilobite-locality Hamar Laghdad (Tafilalt, Morocco) yielded some red-coloured remains of phacopid trilobites. Closer examination revealed that the eyes of these phacopids are often greenish in colour. EDX-analyses showed that the lenses retained their original calcitic composition, possibly greenish due to Fe- and Mn-impurities, while most of the exoskeleton was silicified. The silicified parts contain elevated concentrations of iron which causes the red colour. This phenomenon is explained by the porosity of the exoskeleton in contrast to the homogeneous and massive construction of the lenses and their Mg-content. These incompletely silicified trilobites enabled a reconstruction of the silicification process in trilobites. Their diagenetic alteration probably occurred as a result of events associated with the Cretaceous transgression.
Keywords: Trilobita; taphonomy; diagenesis; silicification; transgression; mud-mounds; Devonian; Morocco

Re-description and neotypification of Archamphiroa jurassica Steinmann 1930, a calcareous red alga from the Jurassic of Argentina - Bucur, Ioan I.; Kießling, Wolfgang; Scasso, Roberto A. (Journal of Paleontology, 2009)
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LP.redesc

Redox processes in subducting oceanic crust recorded by sulfide-bearing high-pressure rocks and veins (SW Tianshan, China) - Li, Jilei; Gao, Jun; Klemd, Reiner; John, Timm; Wang, Xin-Shui (Contributions To Mineralogy and Petrology, 2016)
The oxidized nature of the sub-arc mantle and hence arc magmas is generally interpreted as a result of the migration of subduction-related oxidizing fluids or melts from the descending slab into the mantle wedge. This is of particular importance seeing that the oxidization state of sub-arc magmas seems to play a key role in the formations of arc-related ore deposits. However, direct constraints on the redox state of subducted oceanic crust are sparse. Here, we provide a detailed petrological investigation on sulfide- and oxide-bearing eclogites, blueschists, micaschists, eclogite-facies and retrograde veins from the Akeyazi high-pressure (HP) terrane (NW China) in order to gain insight into the redox processes recorded in a subducting oceanic slab. Sulfides in these rocks are mainly pyrite and minor pyrrhotite, chalcopyrite, bornite, molybdenite, sphalerite and chalcocite, including exsolution textures of bornite–chalcopyrite intergrowth. Magnetite, ilmenite and pyrite occur as inclusions in garnet, whereas sulfides are dominant in the matrix. Large pyrite grains in the matrix contain inclusions of garnet, omphacite and other HP index minerals. However, magnetite replacing pyrite textures are commonly observed in the retrograded samples. The eclogite-facies and retrograde veins display two fluid events, which are characterized by an early sulfide-bearing and a later magnetite-bearing mineral assemblage, respectively. Textural and petrological evidences show that the sulfides were mainly formed during HP metamorphism. Mineral assemblage transitions reveal that the relative oxygen fugacity of subducted oceanic crust decreases slightly with increasing depths. However, according to oxygen mass balance calculations, based on the oxygen molar quantities (nO2), the redox conditions remain constant during HP metamorphism. At shallow levels (<60 km) in the subduction channel, interaction with oxidized fluid seems to have caused an increase of the oxygen fugacity and the oxidation state of exhuming HP rocks. This study suggests that oxygen components are not released in significant amounts during HP metamorphism of subducted oceanic crust and, thus, cannot be responsible for oxidizing the mantle wedge and increasing the oxidation state of sub-arc mantle melts.<br
Keywords: Subducted oceanic crust; Fluids; Oxygen fugacity; Eclogite; Sulfides; Magnetite

Reducing taxonomic noise in problematic fossils: Revision of the incertae sedis genus allonema based on shape analysis - Jarochowska, Emilia; Hierl, Florian; Vinn, Olev; Munnecke, Axel (Bulletin of Geosciences, 2016)
Organisms of unknown biological affinity are widespread in Paleozoic ecosystems and play key ecological roles. Recognition of these roles relies on consistent identification and sound taxonomy, yet many microproblematica lack complex morphological features that could be the basis for qualitative taxonomic diagnoses. Allonema is an incertae sedis calcareous sclerobiont widespread in Paleozoic carbonates. At least seven species of Allonema have been proposed, but their diagnoses based on size ranges overlap. In this work, dimensions of 590 individuals from the Silurian of Estonia and Sweden have been measured. Regression analysis of the dimensions revealed two groups, overlapping in size ranges, but differing significantly in proportions. These groups could be matched with previously described A. botellus and A. moniliforme, but both showed a wider range of sizes than previously reported. Another previously described species, A. minimum, fell within the range of dimensions of A. moniliforme and is proposed to be its junior synonym. Differences in proportions revealed in the study do not seem to be dependent on sedimentary environment or local growth conditions such as competition for space, and thus may represent consistent interspecific variability. Although the affinity of Allonema remains unknown, this quantitative approach to its taxonomy reduces unnecessary species in the genus. The success of this approach may encourage its application to other microproblematica populating the fossil record.
Keywords: Baltica; Devonian; Encrusters; Microproblematica; Pseudobryozoans; Sclerobionts; Wetheredella

Reef-building red algae from an uppermost Permian reef complex as a fossil analogue of modern coralline algal ridges - Chen, Weihan; Wang, Yongbiao; Huang, Yafei; Wang, Tan; Yi, Zhixing; Kießling, Wolfgang (Facies, 2020)
Calcareous red algae have been important components in reefal facies since the Mesozoic but their volumetric contribution to Palaeozoic reefs was usually low. Here, we report a reef-building community dominated by Parachaetetes, a genus of solenoporacean red algae, overgrowing uppermost Permian sponge reefs in Cili (Hunan Province, South China). The fossil assemblage in the community consists of about 88% Parachaetetes, 7% rugose corals, and 5% reef-dwelling organisms, including gastropods, brachiopods, foraminifera and Tubiphytes. Although the biodiversity of this community is far lower than that in modern reefs, the association of red algae and rugose corals shares several attributes with the coral–coralline algal communities of modern tropical reefs. Analysis of sedimentary facies indicates that the reef-building Parachaetetes grew in a turbulent setting near the margin of a carbonate platform, perhaps in a reef-crest environment known from modern coralgal reefs. Although calcifying red algae have been recorded from the Cambrian onwards, this is the oldest site where crustose red algae played a dominant role in reef construction.
CRIS-Team Scopus Importer:2020-08-14
Keywords: Late Permian; Palaeoecology; Reef; Rugose coral; Solenoporacean; South china

Reef expansion during the Triassic: Spread of photosymbiosis balancing climatic cooling - Kießling, Wolfgang (Palaeogeography, Palaeoclimatology, Palaeoecology, 2010)
The PaleoReefs Database indicates that reef abundance increased profoundly during the Triassic period, from a pronounced low in the Early Triassic to a major peak in the Norian. This expansion is also evident when standardizing for sampling. Corresponding to the reef expansion is a relative increase of scleractinian corals as reef builders, whereas the contribution of hypercalcifying sponges and microbes decreased during the Triassic. The numerical expansion of corals is paralleled by a proportional increase of morphological features that are suggestive of photosymbiosis, such that the Norian reef boom might be explained by the spread of photosymbiosis in corals. The geographical expansion of reefs was far less pronounced especially concerning palaeolatitude. Late Triassic reef growth was limited to more or less the same latitudinal range as modern reefs. As oxygen isotope data and new modeling results indicate declining temperatures and CO2 concentrations during the Late Triassic, the lack of latitudinal expansion might be attributed to global cooling. Reef development during the Triassic can thus be explained by the evolutionary spread of photosymbiosis balancing the effects of climatic cooling. © 2009 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LP.reefex
Keywords: Climate; Corals; Evolution; Photosymbiosis; Reefs; Triassic

Reef Fish Beware! Aggressive Mimicry in a Pycnodontid? - Kölbl-Ebert, Martina; Ebert, Martin; Bellwood, David R.; Schulbert, Christian (Abstracts of the 90th Annual Meeting of the Paläontologische Gesellschaft, 2019)
Pycnodontiformes are an extinct order of Actinopterygian fishes, present from the Late Triassic (Norian) to the Eocene. Their mostly deep, laterally compressed bodies and comparatively large fins indicate that these fishes were mostly highly manoeuvrable reef fish. With their characteristic durophagous dentition, columnar to incisiform anterior teeth (on premaxilla and dentary) and the posterior crushing teeth of the prearticular and vomer, the whole group was highly specialized as predators on hard-shelled organisms. In 2016, however, a new pycnodontid was found in the quarry of Ettling (Markt Pförring, Bavaria; Late Jurassic) by the excavation team of the Jura-Museum Eichstätt. The most striking feature of this new pycnodontid, Piranhamesodon pinnatomus Kölbl-Ebert et al., 2018 (JME-ETT4103), is its unusual dentition: It has long, pointed teeth at the front (on premaxilla and dentary), dagger-shaped teeth with a sharp, posterior cutting edge along the exterior-most tooth row of the vomer, and triangular teeth with serrations on their anterior margin along the exterior-most tooth row of the prearticulars. As revealed by CT-scanning, the inner teeth of prearticular and vomer are limpet-shaped cones on a columnar tooth base. The “fangs” along the exterior-most tooth row of the prearticulars and vomer of Piranhamesodon pinnatomus interact like scissors; a comparison of their functional morphology with other actinopterygians stress the exceptional high bite-force (a legacy of their pycnodont ancestry), which is comparable to modern piranhas, suggesting a completely unusual mode of predation compared to all other known pycnodontids. We propose this species to have exploited aggressive mimicry: Seemingly harmless and inconspicuous through the typical pycnodontid shape and possibly aided by corresponding colouring, it may have approached and then attacked unsuspecting other fish in the reef, biting and tearing a mouthful of flesh or fin from their unwary prey. Alternatively, it may also have acted at least occasionally as scavenger.<br
Keywords: Pycnodontiformes; Piranhamesodon; Late Jurassic; Ettling

Reefmounds im unteren Wenlock auf Gotland: Beispiele früher Korallenriffe - Samtleben, Christian; Munnecke, Axel (Meyniana, 1999)
Die Reefmounds im unteren Wenlock auf Gotland sind im doppelten Sinne Riffe in einem Frühstadium: Einerseits bilden sie die erste Phase in der Entwicklung der silurischen Riffkomplexe auf Gotland, andererseits stellen sie in der erdgeschichtlichen Entwicklung moderner Korallenriffe ein Beispiel früher Riffbildungen mit einer nur wenig ausgebildeten Internstruktur und Synökologie dar.   The reefmounds in the Lower Wenlockian of Gotland represent in a twofold sense early stages of reef development. On the one hand, they form the first stage in the development of the reef succession on Gotland, on the other hand, they are early examples of reef formation in the geological history of coral reefs, lacking important criteria of modern reefs like strict internal structure, framework, and complex synecology.
Keywords: Reefmounds; Silurian; Gotland; Cnidaria

Reefs as cradles of evolution and sources of biodiversity in the Phanerozoic - Kießling, Wolfgang; Simpson, Carl; Foote, Michael (Science, 2010)
Large-scale biodiversity gradients among environments and habitats are usually attributed to a complex array of ecological and evolutionary factors. We tested the evolutionary component of such gradients by compiling the environments of the geologically oldest occurrences of marine genera and using sampling standardization to assess if originations tended to be clustered in particular environments. Shallow, tropical environments and carbonate substrates all tend to have harbored high origination rates. Diversity within these environments tended to be preferentially generated in reefs, probably because of their habitat complexity. Reefs were also prolific at exporting diversity to other environments, which might be a consequence of low-diversity habitats being more susceptible to invasions.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LP.reefsa

Reefs - Kießling, Wolfgang (Encyclopedia of Sediments and Sedimentary Rocks, 2003)
UnivIS-Import:2015-04-20:Pub.2003.nat.dgeo.IGM.LP.reefs

REE investigation of the Plattkopf fluorite mineralization an extension of the Vergenoeg fluorite deposit (South Africa) - Günther, Thomas; Klemd, Reiner (BGR-Jahrestagung2014, 2014)
Plattekop hill with its concordant hematite-fluorite ore body represents an extension of the Vergenoeg pipe, one of South Africa's world-class fluorite deposits located in the Bushveld Complex. The pipe-shaped body of Vergenoeg strikes discordantly with a minimum depth of circa 650 meters through the rhyolitic bedrocks of the Palaeoproterozoic Rooiberg Group and accommodates different Fe-mineral dominated rock types, which are enriched in fluorite. Both deposits host an additional commodity in terms of Rare-Earth-Element (REE) minerals in their Fe-oxide (hematite or magnetite) and fluorite rich rocks. These are represented by the fluorocarbonate bastnaesite-(Ce) and the REE-phosphates monazite-(Ce) and xenotime-(Y). Combined whole rock and single grain analyses via XRF and LA-ICP-MS and EMP, respectively show the high REE-potential of the sampled rocks from the uppermost gossan ores of Plattekop and Vergenoeg as well as from their deeper unweathered equivalent rock type with whole rock contents of REEs <4.5 wt. %. Thereby, C1-chondrite normalized REE-patterns show on average (La/Lu)CNratios of <5.3 with a relatively flat trend. The major rock forming minerals contain 100 ppm to 2500 ppm REEs/Fe-oxide and 3000 ppm to 7000 ppm REEs/fluorite on average. The minerals bastnaesite, monazite and xenotime are intercalated between Fe-minerals and fluorites with an abundance of <4 vol. % per sample. The light rare earth elements (LREE) are preferentially incorporated into bastnaesite and monazite with an order of abundance of Ce > La > Nd > Pr in contrast to xenotime, which exhibits enriched concentrations of heavy rare earth elements (HREE) and an order of abundance of Y > Er > Dy > Gd. Average concentrations are between 50 and 60 wt. % REEs/REE-mineral. Petrological and geochemical evidences of sampled rocks suggest a hydrothermal origin for the REE-minerals after the primary mineralization of Vergenoeg and Plattekop precipitated. Secondary fluid inclusions within fluorite record temperatures between 150 °C and 500 °C for late stage hydrothermal events (Borroket al., 1998) from which bastnaesite may have crystallized at intermediate to basic pH conditions. Their alteration to monazite and xenotime marks a change of the hydrothermal conditions to a more acidic and phosphate rich environment. Thereby, balance calculations indicate a renewed REE-enrichment by the P-rich fluids. The remarkable enrichment of fluorite and REE-minerals within the upper 200 meters of Vergenoeg is probably a result of changes in temperature, pressure, and pH of the fluid system due to the channelized upward migration of the hydrothermal solutions towards the top of the pipe and the interaction to the adjacent bedrocks in contact. Regarding the origin of the primary mineralization of Vergenoeg and Plattekop and the mineralizing fluids, negative Eu anomalies (Eu/Eu*) ranging from 0.08 to 0.57 for the Fe-oxides and 0.05 to 0.08 for the fluorites display the influence of reduced conditions in a possible felsic igneous-related source like the Lebowa Granite Suite of the Bushveld Complex. Furthermore, the chemical signature of the Vergenoeg magnetites correlates well with those of igneous Climax-Mo deposits (enriched in Al, Ga, Sn and depleted in Cr, Mg) and therefore, indicates a genetic relationship to the porphyry deposit type.<br

Reentering of an overpressured basin - The south German Molasse - Drews, Michael; Bauer, Wolfgang; Stollhofen, Harald (1st EAGE Workshop on Pore Pressure Prediction: At the Well Scale from Today to Tomorrow, State of the Art, Recent Progress and Technology Gap, 2017)

Re-evaluating the general dynamic theory of oceanic island biogeography - Steinbauer, Manuel; Dolos, Klara; Field, Richard; Reineking, Björn; Beierkuhnlein, Carl (Frontiers of Biogeography, 2013)
The general dynamic model of oceanic island biogeography integrates temporal changes in ecological circumstances with diversification processes, and has stimulated current research in island biogeography. In the original publication, a set of testable hypotheses was analysed using regression models: specifically, whether island data for four diversity indices are consistent with the ‘B ATT2’ model, in which B is a diversity index, A is log(area) and T is time. The four indices were species richness, the number and percentage of single‐island endemic species, and a diversification index. Whether the relationships between these indices and time are unimodal (i.e., ‘hump‐shaped’) was a key focus, based on the characteristic ontogeny of a volcanic oceanic island. However, the significance testing unintentionally used zero, rather than the mean of the diversity index, as the null hypothesis, greatly inflating F‐ values and reducing P‐values compared with the standard regression approach. Here we first re‐analyze the data used to evaluate the general dynamic model in the seminal paper, using the standard null hypothesis, to provide an important qualification of its empirical results. This supports the significance of about half the original tests, the rest becoming non‐significant but mostly suggestive of the hypothesized relationship. Then we expand the original analysis by testing additional, theoretically derived functional relationships between the diversity indices, island area and time, within the framework of the ATT2 model and using a mixed‐effects modelling approach. This shows that species richness peaks earlier in island life‐cycles than endemism. Area has a greater effect on species richness and the number of single‐island endemics than on the proportion of single‐island endemics and the diversification index, and was always better fit as a log–log relationship than as a semi‐log one. Finally, the richness–time relationship is positively skewed, the initial rise happening much more quickly than the later decline.

Refined ettringite (Ca6Al2(SO4)3(OH)12x26H2O) structure for quantitative X-Ray diffraction analysis - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Powder Diffraction, 2006)
A revised structure model of ettringite is presented, in order to provide quantitative X-ray diffraction (QXRD) of this mineral in cement pastes. The model is derived from two different existing structure models, both of which are suitable for restricted use but are inferior to the refined ettringite structure presented. In the first published ettringite structure proposed by Moore and Taylor [Acta Crystallogr. B 26, 386-393 (1970)], none of the 128 positions for H are given in the unit cell, which results in reduced scattering power for use of this model for quantification purposes. For the precise quantification of ettringite in samples together with anhydrous phases, the scattering factors of all atoms including the H positions are indispensable. The revised structure model is based on the data of Moore and Taylor, supplemented by the H positions determined by Berliner (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic, Society, 1998, pp. 127-141) on the basis of a neutron diffraction structural investigation of deuterated ettringite at 20 K. Berliner's (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic Society, 1998, pp. 127-141) thermal parameter should not, however, be used, since a normal application is at room temperature. In order further to improve the structure model of ettringite, Rietveld refinement with the rigid body approach for OH and H2 O molecules and SO4 tetrahedra was employed. The refined and improved ettringite structure model was tested for quantitative phase analysis by the determination of actual ettringite contents in mixtures with an internal standard. Synthesized and orientation-free prepared ettringite powders were investigated by X-ray powder diffraction analysis and quantified in four different blends with zircon. The quantification results with the new structure model demonstrate the superior quality of the revised ettringite structure. © 2006 International Centre for Diffraction Dat
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LM.refine
Keywords: Cement hydration; Ettringite; Quantitative X-ray powder diffraction analysis (QXRPD); Rietveld refinement; Structure

Regional geology of the Skåne province, Sweden - Calner, Mikael; Erlström, Mikael; Eriksson, Mats; Lehnert, Oliver; Ahlberg, Per (The Lower Palaeozoic of southern Sweden and the Oslo Region, Norway. Field Guide for the 3rd Annual Meeting of the IGCP project 591., 2013)
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.lowerp

Regional geology of the Västergötland province, Sweden - Ahlberg, Per; Calner, Mikael; Lehnert, Oliver; Wickström, Linda (The Lower Palaeozoic of southern Sweden and the Oslo Region, Norway. Field Guide for the 3rd Annual Meeting of the IGCP project 591., 2013)
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.region

Regionalization of precipitation in Mauritius: a statistical approach - Raja, Nussaïbah Begum; Aydin, Olgu (Meteorological Applications, 2019)
The aim of this study was to quantify the regional precipitation patterns of Mauritius using the total mean annual precipitation of 52 meteorological stations for the period 1981–2010. Principal component analysis was first used to determine the significant variables influencing precipitation in Mauritius. A cluster analysis was then applied to group the stations according to the significant variables identified. Finally, a spatial interpolation of precipitation in Mauritius using the kriging with external drift technique was carried out to examine the spatial distribution of precipitation on the island. The principal component analysis results showed that elevation and coastal proximity caused the most variance in the dataset with respect to precipitation. Using the cluster analysis and kriging results, six regions of precipitation were determined: three inland and three coastal regions. A decreasing gradient in precipitation between the southeast and northwest is observed due to the southeast trade winds and the altitudinal difference between the coastal areas and the central plateau. The central plateau represents a distinct precipitation zone which receives the highest precipitation on the island. The windward-facing south and eastern highlands experience orographic precipitation as a result of adiabatic air expansion and therefore are more humid. On the other hand, the northeast highlands region, together with the north and western coasts which lie in the leeward rain shadow, are notably drier.
CRIS-Team Scopus Importer:2019-07-02
Keywords: cluster analysis (CA); kriging; Mauritius; precipitation; principal component analysis (PCA); regional precipitation pattern

Regional mudstone compaction trends in the Vienna Basin: top seal assessment and implications for uplift history - Skerbisch, Lukas; Misch, David; Drews, Michael; Stollhofen, Harald; Sachsenhofer, Reinhard F.; Arnberger, Klaus; Schuller, Volker; Zamolyi, Andras (International Journal of Earth Sciences, 2023)
Seal quality assessment is not only essential in petroleum systems studies but also in the context of other geo energy applications such as underground hydrogen storage. Capillary breakthrough pressure controls top seal capacity in the absence of faults or other discontinuities. In basins that lack measured capillary pressure data (e.g., from drill cores), regional compaction-porosity trends can be used as a first prediction tool to estimate the capillary properties of mudstones. Mathematical compaction models exist but need to be calibrated for each basin. This study aims to establish a compaction trend based on theoretical models, then compare it with theoretical maximum hydrocarbon column heights inferred from true measured capillary pressure curves. Middle to upper Miocene mudstone core samples from the Vienna Basin, covering a broad depth interval from 700 to 3400 m, were investigated by X-ray diffractometry, with an Eltra C/S analyzer, and by Rock–Eval pyrolysis for bulk mineralogy, total organic carbon, and free hydrocarbon contents. Broad ion beam—scanning electron microscopy, mercury intrusion capillary porosimetry, and helium pycnometry were applied to obtain pore structural properties to compare the mathematical compaction models with actual porosity data from the Vienna Basin. Clear decreasing porosity depth trends imply that mechanical compaction was rather uniform in the central Vienna Basin. Comparing the Vienna Basin trend to global mudstone compaction trends, regional uplift causing erosion of up to 500 m upper Miocene strata is inferred. A trend of increasing Rock–Eval parameters S1 and production index [PI = S1/(S1 + S2)] with decreasing capillary sealing capacity of the investigated mudstones possibly indicates vertical hydrocarbon migration through the low-permeable mudstone horizons. This observation must be considered in future top-seal studies for secondary storage applications in the Vienna Basin.
CRIS-Team Scopus Importer:2023-08-11
Keywords: BIB-SEM; Helium pycnometry; MICP; Mudstone compaction; Top seal quality; Uplift history; Vienna Basin

Regional-scale paleofluid system across the Tuscan Nappe-Umbria-Marche Apennine Ridge (northern Apennines) as revealed by mesostructural and isotopic analyses of stylolite-vein networks - Beaudoin, Nicolas E.; Labeur, Aurelie; Lacombe, Olivier; Köhn, Daniel; Billi, Andrea; Hoareau, Guilhem; Boyce, Adrian; John, Cedric M.; Marchegiano, Marta; Roberts, Nick M.; Millar, Ian L.; Claverie, Fanny; et al. (Solid Earth, 2020)
We report the results of a multiproxy study that combines structural analysis of a fracture-stylolite network and isotopic characterization of calcite vein cements and/or fault coating. Together with new paleopiezometric and radiometric constraints on burial evolution and deformation timing, these results provide a first-order picture of the regional fluid systems and pathways that were present during the main stages of contraction in the Tuscan Nappe and Umbria-Marche Apennine Ridge (northern Apennines). We reconstruct four steps of deformation at the scale of the belt: burial-related stylolitization, Apenninic-related layer-parallel shortening with a contraction trending NE-SW, local extension related to folding, and late-stage fold tightening under a contraction still striking NE-SW. We combine the paleopiezometric inversion of the roughness of sedimentary stylolites - that constrains the range of burial depth of strata prior to layer-parallel shortening - with burial models and U-Pb absolute dating of fault coatings in order to determine the timing of development of mesostructures. In the western part of the ridge, layer-parallel shortening started in Langhian time (similar to 15 Ma), and then folding started at Tortonian time (similar to 8 Ma); late-stage fold tightening started by the early Pliocene (similar to 5 Ma) and likely lasted until recent/modern extension occurred (similar to 3 Ma onward). The textural and geochemical (delta O-18, delta C-13, Delta 47CO2 and Sr-87/Sr-86) study of calcite vein cements and fault coatings reveals that most of the fluids involved in the belt during deformation either are local or flowed laterally from the same reservoir. However, the western edge of the ridge recorded pulses of eastward migration of hydrothermal fluids (>140 degrees C), driven by the tectonic contraction and by the difference in structural style of the subsurface between the eastern Tuscan Nappe and the Umbria-Marche Apennine Ridge.
CRIS-Team WoS Importer:2020-09-25

Reinvestigation of the Fe-rich part of the pseudo-binary system SrO-Fe_2_O_3_ - Langhof, Nico; Seifert, Daniela; Göbbels, Matthias; Toepfer, Joerg (Journal of Solid State Chemistry, 2009)
The phase relations in the Fe-rich part of the pseudo-binary system SrO–Fe2O3 (>33 mol% Fe2O3) were reinvestigated between 800 and 1500 °C in air. A combination of microscopy, electron probe micro-analysis, powder X-ray diffraction and thermal analysis was used to determine phase relations, crystal structure parameters and phase transition temperatures. M-type hexagonal ferrite SrFe12O19 (85.71 mol% Fe2O3) is stable up to 1410 °C. No indication of a significant phase width was found; Sr4Fe6O13±δ appears as a second phase in compositions with <85.71±0.2 mol% Fe2O3. Sr4Fe6O13±δ itself is stable between 800 and 1250 °C. Two other hexagonal ferrites were found to exist at high temperatures only: W-type SrFe2+2Fe3+16O27 is stable between 1350 and 1440 °C and X-type ferrite Sr2Fe2+2Fe3+28O46 between 1350 and 1420 °C, respectively, which is shown here for the first time. These findings in combination with previously published data were used to derive a corrected phase diagram of the Fe-rich part of the pseudo-binary system SrO–Fe2O3.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.reinve
Keywords: Hexagonal ferrites; Hard magnets; Phase diagram; Sr–Fe–O

Rekonstruktion orbital gesteuerter Klimaschwankungen eine Fallstudie an pelagischen Karbonaten der norddeutschen Oberkreide - de Wall, Helga; et al. (Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 2005)
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.c3tekt.rekons

Relating ettringite formation and rheological changes during the initial cement hydration: A comparative study applying XRD analysis, rheological measurements and modeling - Jakob, Cordula; Jansen, Daniel; Ukrainczyk, Neven; Koenders, Eddie; Pott, Ursula; Stephan, Dietmar; Neubauer, Jürgen (Materials, 2019)
In order to gain a deeper understanding of the rheological development of hydrating ordinary Portland cement (OPC) pastes at initial state, and to better understand their underlying processes, quantitative X-ray diffraction (XRD) analysis and rheological measurements were conducted and their results combined. The time-dependent relation between phase development and flow behavior of cement paste was investigated at two different temperatures (20 and 30 °C), over a period of two hours. Regarding the phase development during hydration, ettringite precipitation was identified as the dominant reaction in the first two hours. For both temperatures, the increasing ettringite content turned out to correlate very well with the loss of workability of the reacting cement paste. An exponential relationship between ettringite growth and flow behavior was observed that could be explained by applying the Krieger-Dougherty equation, which describes the influence of solid fraction on the viscosity of a suspension.
CRIS-Team Scopus Importer:2019-10-01
Keywords: Ettringite formation; Hydration kinetics; Modeling; OPC; Rheology; Scanning electron microscopy (SEM); Temperature

Relating phase transitions to pore size distributions and mechanical mortar properties in CSA-OPC-C based systems – The potential impact of delayed straetlingite formation - Wolf, Julian; Jansen, Daniel; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Cement and Concrete Research, 2021)
The scope of this research is to investigate the performance evolution of five ternary CSA-OPC-Cs systems. Time resolved thermodynamic modeling was employed to gain insight into changes in the volume fractions of the hydrating pastes and link these changes to trends in the pore size distributions of the mortars. Pore solution analyses were performed to investigate which hydrates have the potential to exert high crystallization pressures. In three out of five blends the resulting tensile stress exceeded the tensile strength of the materials, resulting in the occurrence of coarse pores, which could be linked to the measured compressive strengths. Two damaging crystallization processes were identified in the investigated blends. One is the continuous precipitation of ettringite at high supersaturation in a system with high anhydrite addition. The other is the delayed crystallization of straetlingite at high supersaturation and crystallization pressure in the confined environment of mature pastes.
CRIS-Team Scopus Importer:2021-06-18
Keywords: Calcium sulfoaluminate cement; Crystallization pressure; Pore size distribution; Portland cement; Strätlingite

Relationship between stylolite morphology and the sealing potential of stylolite-bearing carbonate cap rocks - Wu, Jun; Fan, Tailiang; Gomez-Rivas, Enrique; Cao, Qian; Travé, Anna; Gao, Zhiqian; Kang, Zhihong; Köhn, Daniel; Bons, Paul D. (Geological Society of America Bulletin, 2023)
We analyzed the sealing effectiveness of cap rocks bearing different types of stylolites using a combination of petrographic, petrophysical, pore structure, and sealing capacity characterization techniques. This study was based on examples of carbonate cap rocks that seal ultradeep hydrocarbon reservoirs of the Tarim Basin (China). Samples from both drill cores and their outcrop analogues were investigated to quantify how morphology influences the sealing capacity of different types of stylolite-bearing rocks. The study cap rocks consisted of mudstone, wackestone to packstone, grainstone, and dolomitic limestone. Four types of stylolites were identified: rectangular layer, seismogram pinning, suture and sharp peak, and simple wave-like types. The difference in the sealing capacity of carbonate cap rocks is attributed to their pore structure connections and the types of stylolites they develop. Samples bearing simple wave-like stylolites showed the best sealing capacity, followed by those with rectangular layer and suture and sharp peak types, whereas carbonates hosting seismogram pinning types had the lowest sealing capacity. The impact of stylolite segments on the rock sealing properties, however, differed from one segment to another. Rectangular layer–type stylolites could be divided into three distinct segments (with good, moderate, and poor sealing, respectively). Both the seismogram pinning and suture and sharp peak stylolite types were divided in two parts, with the former one having moderate and poor sealing and the latter exhibiting good and moderate sealing. The simple wavelike type had a good sealing capacity all along the pressure-solution seam. The most effective sealing barriers for vertical fluid flow form when (1) calcite and siliceous cements are pervasively distributed in the vicinity of stylolites, forming highly cemented zones with lower porosity and permeability than their surrounding host rocks; (2) stylolites are enriched in insoluble residues; and (3) rare microfractures and dissolution vugs are found along the stylolites. This work provides useful examples for the prediction of the sealing potential of stylolite-bearing carbonate rocks according to stylolite morphology in other geologic settings.
CRIS-Team Scopus Importer:2023-03-31

Relationship between thermal conductivity and saturation conditions in soils interested by very shallow geothermal systems: an overview of ITER Project - Di Sipio, Eloisa; Bertermann, David (44th NATAS (North American Thermal Analysis Society) Conference, 2017)

Relationships between fracture toughness, Y2O3 fraction and phases content in modern dental Yttria-doped zirconias - Belli, Renan; Hurle, Katrin; Schürrlein, Jana; Petschelt, Anselm; Werbach, Katharina; Peterlik, Herwig; Rabe, Torsten; Mieller, Björn; Lohbauer, Ulrich (Journal of the European Ceramic Society, 2021)
The relationship between fracture toughness and Yttria content in modern zirconia ceramics was revised. For that purpose, we evaluated here 10 modern Y2O3-stabilized zirconia (YSZ) materials currently used in biomedical applications, namely prosthetic and implant dentistry. The most relevant range between 2-5 mol% Y2O3 was addressed by selecting from conventional opaque 3 mol% YSZ up to more translucent compositions (4−5 mol% YSZs). A technical 2YSZ was used to extend the range of our evaluation. The bulk mol% Y2O3 concentration was measured by X-Ray Fluorescence Spectroscopy. Phase quantification by Rietveld refinement considered two tetragonal phases or an additional cubic phase. A first-account of the fracture toughness (KIc) of the pre-sintered blocks is given, which amounted to 0.4 – 0.7 MPa√m. In the fully-densified state, an inverse power-law behavior was obtained between KIc and bulk mol% Y2O3 content, whether using only our measurements or including literature data, challenging some established relationships. A linear relationship between KIc and the fraction of the transformable t-phase was established within the range of 30–70 vol%.
CRIS-Team Scopus Importer:2021-10-08
Keywords: Dental; Fracture toughness; Power-law; X-ray-diffraction; Yttria; Zirconia

Relative rates of fluid advection, elemental diffusion and replacement govern reaction front patterns - Köhn, Daniel; Piazolo, Sandra; Beaudoin, Nicolas E.; Kelka, Ulrich; Spruženiece, Liene; Putnis, Christine V.; Toussaint, Renaud (Earth and Planetary Science Letters, 2021)
Replacement reactions during fluid infiltration into porous media, rocks and buildings are known to have important implications for reservoir development, ore formation as well as weathering. Natural observations and experiments have shown that in such systems the shape of reaction fronts can vary significantly ranging from smooth, rough to highly irregular. It remains unclear what process-related knowledge can be derived from these reaction front patterns. In this contribution we show a numerical approach to test the effect of relative rates of advection, diffusion, and reaction on the development of reaction fronts patterns in granular aggregates with permeable grain boundaries. The numerical model takes (i) fluid infiltration along permeable grain boundaries, (ii) reactions and (iii) elemental diffusion into account. We monitor the change in element concentration within the fluid, while reactions occur at a pre-defined rate as a function of the local fluid concentration. In non-dimensional phase space using Péclet and Damköhler numbers, results show that there are no rough fronts without advection (Péclet<70) nor if the reaction is too fast (Damköhler>10−3). As advection becomes more dominant and reaction slower, roughness develops across several grains with a full microstructure mimicking replacement in the most extreme cases. The reaction front patterns show an increase in roughness with increasing Péclet number from Péclet 10 to 100 but then a decrease in roughness towards higher Péclet numbers controlled by the Damköhler number. Our results indicate that reaction rates are crucial for pattern formation and that the shape of reaction fronts is only partly due to the underlying transport mechanism.
CRIS-Team Scopus Importer:2021-05-07
Keywords: advection; diffusion; grain boundary network; reaction front; replacement; roughness

Reliable estimates of beta diversity with incomplete sampling - Roden, Vanessa; Kießling, Wolfgang (GSA Annual Meeting in Seattle, Washington, USA - 2017, 2017)

Reliable estimates of beta diversity with incomplete sampling - Roden, Vanessa; Kocsis, Ádám; Zuschin, Martin; Kießling, Wolfgang (Ecology, 2018)
Beta diversity, the compositional variation among communities or assemblages, is crucial to understanding the principles of diversity assembly. The mean pairwise proportional dissimilarity expresses overall heterogeneity of samples in a data set and is among the most widely used and most robust measures of beta diversity. Obtaining a complete list of taxa and their abundances requires substantial taxonomic expertise and is time consuming. In addition, the information is generally incomplete due to sampling biases. Based on the concept of the ecological significance of dominant taxa, we explore whether determining proportional dissimilarity can be simplified based on dominant species. Using simulations and six case studies, we assess the correlation between complete community compositional data and reduced subsets of a varying number of dominant species. We find that gross beta diversity is usually depicted accurately when only the 80th percentile or five of the most abundant species of each site is considered. In data sets with very high evenness, at least the 10 most abundant species should be included. Focusing on dominant species also maintains the rank-order of beta diversity among sites. Our new approach will allow ecologists and paleobiologists to produce a far greater amount of data on diversity patterns with less time and effort, supporting conservation studies and basic scienc
Keywords: beta diversity; Bray-Curtis dissimilarity; community composition; distance matrices; dominant species; heterogeneity; proportional dissimilarity; sampling

Remagnetisation and magnetic refraction in proterozoic dykes from Central Scandinavia during Caledonian deformation - de Wall, Helga; et al. (PHYS CHEM EARTH PT A, 2000)

Remarks on the Permian dasycladalean alga Sinoporella leei Yabe, 1949 - Bucur, Ioan I.; Munnecke, Axel; Granier, Bruno; Yan, Jiaxin (Geobios, 2009)
Sinoporella leei was first described and illustrated by Yabe in 1949 as a new species and was ascribed to a new subgenus of the genus Triploporella (Steinmann). This alga was not illustrated again until Mu published 25-years later a photomicrograph of a longitudinal-tangential section. The recent finding of new specimens in Permian strata of the Guangxi region (South China) allows us to better illustrate this alga, and to improve our understanding of its morphology to the extent that we find it necessary to emend the current diagnosis. The new observations focus mainly on the morphology of the second-order laterals, on their relationship to the first-order laterals, and the connection of the first-order laterals to the main stem. These data suggest that Sinoporella represents a self-standing, discrete genus that differs from Triploporella. We also consider the lack of cystophores (cyst containers sensu De Castro) and the possible occurrence of individual cysts in the first order laterals as characteristics that do not accord with Barttolo's emended diagnosis of Triploporella. © 2009 Elsevier Masson SAS. All rights reserved.
Keywords: Dasycladalean alga; Permian; Sinoporella; First description

Renewable energy potentials for the post-socialist urban environments of Ub (Serbia) – A shallow geothermal approach - Müller, Johannes; Jocic, Nikola; Pozar, Tea; Bertermann, David (Book of Abstracts / 8th International Urban Geographies of Post-communist States Conference, 2019)

Renewable energy sources in a post-socialist transitional environment: The influence of social geographic factors on potential utilization of very shallow geothermal energy within heating systems in small serbian town of Ub - Jocic, Nikola; Müller, Johannes; Požar, Tea; Bertermann, David (Applied Sciences, 2020)
Energetic stability is a precondition for a regular functioning of society and economy. Actual climate change raised the awareness of population and policy makers about the importance of exploited energy sources. Renewable energy sources are revealed as the solution which should satisfy both needs-a need for energetic stability, as well as a need for producing 'clean' and 'sustainable' energy, and therefore reduce humans' influence on the climate change. Very shallow geothermal energy offers wide range for utilization, among others for heating and cooling living spaces. This article shows potentials of low temperature heating system networks in a small Serbian town of Ub. In addition to technical possibilities, this article combines geographical and social, as well as political and economic circumstances in the town of Ub, which emerge as a result of a complex (post-socialist) transitional vortex.
CRIS-Team Scopus Importer:2020-05-22
Keywords: Low temperature district heating; Post-socialist transitional environment; Renewable energy sources; Very shallow geothermal potential (vSGP)

Repeated Folding during Late Holocene Earthquakes on the La Cal Thrust Fault near Mendoza City (Argentina) - Salomon, Eric; Schmidt, Silke; Hetzel, Ralf; Mingorance, Francisco; Hampel, Andrea (Bulletin of the Seismological Society of America, 2013)
In 1861, one of the most destructive earthquakes in the history of Argentina destroyed the city of Mendoza (currently 1 million inhabitants). The magnitude M-S similar to 7.0 earthquake is inferred to have occurred on the 31-km-long La Cal thrust fault, which extends from Mendoza to the north, where it offsets an alluvial fan and small inset terraces along a well-preserved fault scarp. A trench excavated on a terrace that is vertically offset by similar to 2.5 m exposes two main stratigraphic units separated by an erosional unconformity. The coarse-grained upper unit is deformed by three east-vergent folds (F-1-F-3). Retrodeformation of these folds yields total displacements of similar to 2.0 m, similar to 2.4 m, and similar to 0.5 m on the underlying fault splays, respectively. The displacement of similar to 2.0 m recorded by fold F-1 is interpreted as the result of the fault rupture that caused the 1861 earthquake. F-2 and F-3 were presumably generated during the penultimate event with an inferred magnitude of M-w similar to 7.0, although formation during two distinct ruptures cannot be excluded. Finite-element modeling shows that coseismic folding above the tip of a blind thrust fault is a physically plausible mechanism to generate these folds. A published luminescence age of 770 +/- 76 years, which is interpreted to date the formation of the deformed terrace, indicates that the two (or possibly three) scarp-forming events occurred during the last similar to 800 years. The fine-grained sediments below the erosional unconformity-that contain evidence for at least one older earthquake-are dated at similar to 12 kyr. Our results indicate that elastic strain energy, which is accumulating at the front of the Precordillera today as shown by Global Positioning System (GPS) data, was repeatedly released during earthquakes on the La Cal fault in the past. Hence, the La Cal thrust fault poses a serious threat to the city of Mendoza.

Reply on Comment by Longinelli (2013) on a revised phosphate-water fractionation equation - Puceat, E.; Joachimski, Michael; Bouilloux, A.; Monna, Fabrice; Bonin, A.; Motreuil, S.; Moriniere, P.; Henard, S.; Mourin, J.; Dera, G.; Quesne, D. (Earth and Planetary Science Letters, 2013)

Reply to Comments by Kale and Pande on: “Machine-learning based re-classification of the stratigraphy of the Rajahmundry Traps, India” - Hoyer, Patrick; Regelous, Marcel; Adatte, Thierry; Haase, Karsten (Journal of Volcanology and Geothermal Research, 2023)
CRIS-Team Scopus Importer:2023-05-26

Reply to discussion by RN Scoon and AA Mitchell on 'Oxygen isotope and trace element compositions of platiniferous dunite pipes of the Bushveld Complex, South Africa - Signals from a recycled mantle component?' - Günther, Thomas; Haase, Karsten; Junge, Malte; Oberthuer, Thomas; Wölki, Dominic; Krumm, Stefan (Lithos, 2019)
CRIS-Team WoS Importer:2019-02-22

Reply to the Discussion by Maravelis and Zelilidis on "Unravelling provenance from Eocene-Oligocene sandstones of the Thrace Basin, North-east Greece" by Caracciolo etal. (2011), Sedimentology, 58, 1988-2011. - Caracciolo, Luca; et al. (Sedimentology, 2013)
Keywords: Compositional signatures; Limnos Island; NAegean evolution; provenance; Thrace basin

Research on mechanical parameters of coarse-grained sliding soil based on CT scanning and numerical tests - Jiang, Jiwei; Xiang, Wei; Schleier, Markus; Pan, Jiajun; Zhang, Wei; Rohn, Joachim (Landslides, 2016)
Keywords: CT scanning; Mechanical parameters; Nondestructive testing; Numerical test; Rock and soil aggregates (RSA); Sliding soil

Research on water–rock (soil) interaction by dynamic tracing method for Huangtupo landslide, Three Gorges Reservoir, PR China - Jiang, Ji-Wei; Xiang, Wei; Zeng, Wen; Schleier, Markus; Rohn, Joachim (Environmental Earth Sciences, 2015)
Keywords: Bad geological elements; Clay mineral; Huangtupo landslide; Multi-sample dynamic tracing method; Three Gorges Reservoir; Water and rock (soil) interaction

Reservoir and Cap Rock Monitoring - Kühn, Michael; Barth, Johannes; Baumann, G.; Becker, Veith; Bock, M.; Buske, S.; Fritschen, R.; Giese, R.; Groß, C.; Henninges, J.; Houpt, L.; Kock, D.; et al. (CLEAN, 2013)

Resilience of cold-water scleractinian corals to ocean acidification: Boron isotopic systematics of pH and saturation state up-regulation - McCulloch, Malcolm; Trotter, Julie; Montagna, Paolo; Falter, Jim; Dunbar, Robert; Freiwald, André; Försterra, Günter; López Correa, Matthias; Maier, Cornelia; Rüggeberg, Andres; Taviani, Marco (Geochimica Et Cosmochimica Acta, 2012)
The boron isotope systematics has been determined for azooxanthellate scleractinian corals from a wide range of both deep-sea and shallow-water environments. The aragonitic coral species, Caryophyllia smithii, Desmophyllum dianthus, Enallopsammia rostrata, Lophelia pertusa, and Madrepora oculata, are all found to have relatively high δ 11B compositions ranging from 23.2‰ to 28.7‰. These values lie substantially above the pH-dependent inorganic seawater borate equilibrium curve, indicative of strong up-regulation of pH of the internal calcifying fluid (pH cf), being elevated by 0.6-0.8units (ΔpH) relative to ambient seawater. In contrast, the deep-sea calcitic coral Corallium sp. has a significantly lower δ 11B composition of 15.5‰, with a corresponding lower ΔpH value of 0.3units, reflecting the importance of mineralogical control on biological pH up-regulation.The solitary coral D. dianthus was sampled over a wide range of seawater pH T and shows an approximate linear correlation with ΔpH Desmo=6.43-0.71pH T (r 2=0.79). An improved correlation is however found with the closely related parameter of seawater aragonite saturation state, where ΔpH Desmo=1.09-0.14Ω arag (r 2=0.95), indicating the important control that carbonate saturation state has on calcification. The ability to up-regulate internal pH cf, and consequently Ω cf, of the calcifying fluid is therefore a process present in both azooxanthellate and zooxanthellate aragonitic corals, and is attributed to the action of Ca 2+-ATPase in modulating the proton gradient between seawater and the site of calcification. These findings also show that the boron isotopic compositions (δ 11B carb) of aragonitic corals are highly systematic and consistent with direct uptake of the borate species within the biologically controlled extracellular calcifying medium.We also show that the relatively strong up-regulation of pH and consequent elevation of the internal carbonate saturation state (Ω cf 8.5 to 13) at the site of calcification by cold-water corals, facilitates calcification at or in some cases below the aragonite saturation horizon, providing a greater ability to adapt to the already low and now decreasing carbonate ion concentrations. Although providing greater resilience to the effects of ocean acidification and enhancing rates of calcification with increasing temperature, the process of internal pH cf up-regulation has an associated energetic cost, and therefore growth-rate cost, of 10% per 0.1 pH unit decrease in seawater pH T. Furthermore, as the aragonite saturation horizon shoals with rapidly increasing pCO 2 and Ω arag<1, increased dissolution of the exposed skeleton will ultimately limit their survival in the deep oceans. © 2012 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LP.resili
Keywords: ocean acidification; coral calcification; biomineralization

Resistivity relaxation, a new approach to study ionic mobility in perovskite mixed conductors like CaTi0.7Fe0.3O3-ð - Mashkina, Elena; Baier, Markus; Magerl, Andreas; Göbbels, Matthias; Seifert, Friedrich (Ionics, 2005)
Oxygen transport of mixed ionic-electronic conductors can be measured by a 'relaxation' technique that permits to investigate the material dynamic properties with oxygen partial pressure change. However, for materials exhibiting higher electronic conductivity than ionic, the time for conductivity change is controlled by bulk ionic transport and any surface reaction can be neglected. By fitting the experimental relaxation data of CaTi 0.7Fe0.3O3-δ composition, the oxidation and reduction kinetics was found to be independent on oxygen partial pressure (PO2) and the rate constants were derived therefrom. From a relaxation experiment at a single PO2 we therefore obtain both the electronic and ionic contributions to the total conductivity as well as the chemical diffusion coefficient.
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LM.resist

Response - Kießling, Wolfgang (Science, 2010)

Response of an Arctic calcifying macro alga to increasing CO2 and temperature Levels: A habitat at risk? - Büdenbender, Jan; Hellemann, D.; Teichert, Sebastian; Stange, P.; Form, Armin; Riebesell, U. (EPOCA Final meeting, 2012)

Response of Siliceous Marine Organisms to the Permian-Triassic Climate Crisis Based on New Findings From Central Spitsbergen, Svalbard - Foster, W. J.; Asatryan, G.; Rauzi, S.; Botting, J. P.; Buchwald, S. Z.; Lazarus, D. B.; Isson, T.; Renaudie, J.; Kießling, Wolfgang (Paleoceanography and Paleoclimatology, 2023)
Siliceous marine ecosystems play a critical role in shaping the Earth's climate system by influencing rates of organic carbon burial and marine authigenic clay formation (i.e., reverse weathering). The ecological demise of silicifying organisms associated with the Permian-Triassic mass extinction is postulated to have elevated marine authigenic clay formation rates, resulting in a prolonged greenhouse climate during the Early Triassic. Yet, our understanding of the response of siliceous marine organisms during this critical interval is poor. Whilst radiolarians experienced the strongest diversity loss in their evolutionary history and perhaps also the greatest population decline of silica-secreting organisms during this event, only a small number of Griesbachian (post-extinction) localities that record siliceous organisms are known. Here, we report newly discovered latest Changhsingian to early Griesbachian (Clarkina meishanensis - Hindeodus parvus Zone) radiolarians and siliceous sponge spicules from Svalbard. This fauna documents the survival of a low-diversity radiolarian assemblage alongside stem-group hexactinellid sponges making this the first described account of post-extinction silica-secreting organisms from the Permian/Triassic boundary in a shallow marine shelf environment and a mid-northern paleolatitudinal setting. Our findings indicate that latitudinal diversity gradients for silica-secreting organisms following the mass extinction were significantly altered, and that silica productivity was restricted to high latitude and deep water thermal refugia. This result has potential to further shape our understanding of changes in marine dissolved silica levels and in turn rates of reverse weathering, with implications for our understanding of carbon cycle dynamics during this interval.
CRIS-Team Scopus Importer:2023-12-15
Keywords: climate response; hexactinellids; Permian-Triassic; radiolarians; thermal stress

Response to comment on "Lethally hot temperatures during the Early Triassic. - Sun, Yadong; Joachimski, Michael; Wignall, Paul B.; Yan, Chunbo; Chen, Yanlong; Jiang, Haishui; Wang, Lina; Lai, Xulong; Sun, Yadong (Science, 2013)
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.respon

Response to comments on "Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates - Kießling, Wolfgang; et al. (Science, 2006)
UnivIS-Import:2015-04-14:Pub.2006.nat.dgeo.IGM.LP.respon

REVEALING THE GENESIS OF LIMESTONE-MARL ALTERNATIONS: A TAPHONOMIC APPROACH - Nohl, Theresa; Jarochowska, Emilia; Munnecke, Axel (Palaios, 2019)

Revised correlation of Silurian Provincial Series of North America with global and regional chronostratigraphic units and δ13Ccarb chemostratigraphy - Cramer, Bradley D.; Brett, Carlton E.; Melchin, Michael J.; Männik, Peep; Kleffner, Mark A.; Mclaughlin, Patrick I.; Loydell, David K.; Munnecke, Axel; Jeppsson, Lennart; Corradini, Carlo; Brunton, Frank R.; Saltzman, Matthew Ross (Lethaia, 2011)
Recent revisions to the biostratigraphic and chronostratigraphic assignment of strata from the type area of the Niagaran Provincial Series (a regional chronostratigraphic unit) have demonstrated the need to revise the chronostratigraphic correlation of the Silurian System of North America. Recently, the working group to restudy the base of the Wenlock Series has developed an extremely high-resolution global chronostratigraphy for the Telychian and Sheinwoodian stages by integrating graptolite and conodont biostratigraphy with carbonate carbon isotope (δC) chemostratigraphy. This improved global chronostratigraphy has required such significant chronostratigraphic revisions to the North American succession that much of the Silurian System in North America is currently in a state of flux and needs further refinement. This report serves as an update of the progress on recalibrating the global chronostratigraphic correlation of North American Provincial Series and Stage boundaries in their type area. The revised North American classification is correlated with global series and stages as well as regional classifications used in the United Kingdom, the East Baltic, Australia, China, the Barrandian, and Altaj. Twenty-four potential stage slices, based primarily on graptolite and conodont zones and correlated to the global series and stages, are illustrated alongside a new composite δC curve for the Silurian. Conodont, graptolite, isotope, New York, Ontario, series, Silurian, stage. © 2010 The Authors, Journal compilation © 2010 The Lethaia Foundatio
Keywords: Chronostratigraphy; Silurian; Provincial Series; δ13C; Chemostratigraphy

Revised phosphate-water fractionation equation reassessing paleotemperaturesderived from biogenic apatite. - Puceat, E.; Joachimski, Michael; Bouilloux, A.; Monna, Fabrice; Bonin, A.; Motreuil, S.; Moriniere, P.; Henard, S.; Mourin, J.; Dera, Guillaume; Quesne, D. (Earth and Planetary Science Letters, 2010)
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LG.revise

Revision of thelodonts, acanthodians, conodonts, and the depositional environments in the Burgen outlier (Ludlow, Silurian) of Gotland, Sweden - Jarochowska, Emilia; Bremer, Oskar; Yiu, Alexandra; Märss, Tiiu; Blom, Henning; Mörs, Thomas; Vajda, Vivi (GFF, 2021)
Ludfordian strata exposed in the Burgen outlier in eastern Gotland record a time of initial faunal recovery after a global environmental perturbation manifested in the Ludfordian Carbon Isotope Excursion (LCIE). Vertebrate microfossils in the collection of the late Lennart Jeppsson, hosted at the Swedish Museum of Natural History, hold the key to reconstruct the dynamics of faunal immigration and diversification during the decline of the LCIE, but the stratigraphic relationships of the strata have been debated. Historically, they had been placed in the Burgsvik Formation, which included the Burgsvik Sandstone and the Burgsvik Oolite members. We revise the fauna in the Jeppsson collection and characterize key outcrops of Burgen and Kapellet. The former Burgsvik Oolite Member is here revised as the Burgen Oolite Formation. In the Burgen outlier, back-shoal facies of this formation are represented and their position in the Ozarkodina snajdri Biozone is supported. The shallow-marine position compared to the coeval strata in southern Gotland is reflected in the higher δ13Ccarb values, reaching +9.2‰. The back-shoal succession includes high-diversity metazoan reefs, which indicate a complete recovery of the carbonate producers as the LCIE declined. The impoverishment of conodonts associated with the LCIE in southern Gotland might be a product of facies preferences, as the diverse environments in the outlier yielded all 21 species known from the formation. Fish diversity also returned to normal levels as the LCIE declined, with a minimum of nine species. In line with previous reports, thelodont scales appear to dominate samples from the Burgen outlier.<br
Keywords: acanthodians; biostratigraphy; Burgsvik Formation; Ludlow; thelodonts; Lau event; carbon isotope excursion; extinction; recovery; palynology

Revisiting reef models in the Oligocene of northern Italy (Venetian Southern Alps) - Bosellini, Francesca R.; Vescogni, Alessandro; Kießling, Wolfgang; Zoboli, Alessandro; Di Giuseppe, Dario; Papazzoni, Cesare Andrea (Bollettino Della Societa Paleontologica Italiana, 2020)
The lower Oligocene coral communities and reefs exposed in the Lessini Shelf of northern Italy may record one of the oldest well-developed barrier reef/lagoon systems of the Cenozoic. However, the rimmed-shelf interpretation has been repeatedly challenged in favour of a ramp model with scattered corals. Based upon a re-analysis of selected localities in the Lessini Shelf, we here provide support for the barrier reef model based on four key observations: 1) systematic changes of coral growth-forms from branching in the proximal areas to massive at the platform margin; 2) a progressive increase of the hydrodynamic energy from the proximal belt towards the more distal environments in the Berici Hills; 3) the occurrence of shallow-water, euphotic conditions throughout the whole depositional system; and 4) the presence of restricted circulation in the proximal environments during sea-level lowstands, with lack of coral colonies. These features, together with the evidence of coral frameworks located on the southeastern edge of the Lessini Shelf, substantiate the occurrence of a reef-rimmed margin. The reefal rim acted as an efficient barrier, with the formation of a landward, wide lagoon protected from the action of waves and currents.
CRIS-Team WoS Importer:2021-01-29

Revisiting the identification of Syllipsimopodi bideni and timing of the decabrachian-octobrachian divergence - Klug, Christian; Stevens, Kevin; Hoffmann, René; Zatoń, Michał; Clements, Thomas; Košťák, Martin; Weis, Robert; De Baets, Kenneth; Lehmann, Jens; Vinther, Jakob; Fuchs, Dirk (Nature Communications, 2023)
CRIS-Team Scopus Importer:2023-12-15

Revisiting the long-term biodiversity dynamics of reef builders in a novel Bayesian framework - Raja Schoob, Nussaibah Begum; Kießling, Wolfgang (13th International Symposium on Fossil Cnidaria, 2019)

REY and Trace Element Chemistry of Fluorite from Post-Variscan Hydrothermal Veins in Paleozoic Units of the North German Basin - Nadoll, Patrick; Rehm, Meike; Duschl, Florian; Klemd, Reiner; Kraemer, Dennis; Sosnicka, Marta (Geosciences, 2018)
Hydrothermal fluorites from Paleozoic sedimentary rocks and volcanic units in the North German Basin (NGB) have been investigated to create a petrographic and geochemical inventory—with particular focus on strategic elements such as rare earth elements (REE)—and to uncover possible links between the post-Variscan hydrothermal mineralization in the NGB and bordering areas such as the Harz Mountains and Flechtingen Calvörde Block (FCB). Fluorites from ten localities underwent a detailed petrographic examination, including SEM-BSE/CL imagery, and were compositionally analysed using LA-ICP-MS. Overall, REY concentrations are comparatively low in fluorite from all investigated areas—the median sum of REY ranges from 0.3 to 176 ppm. EuropiumCN anomalies are slightly negative or absent, indicating that either the formation fluid experienced temperatures above 250 °C or that fluid-rock interactions and REE enrichment was likely controlled by the source rock (i.e., volcanic) composition and complexation processes. Fluorites from the Altmark-Brandenburg Basin (ABB) and the Lower Saxony Basin (LSB) display distinctly different REYCN signatures, suggesting that fluid compositions and genetic processes such as fluid-rock interaction differed significantly between the two areas. Complex growth zones and REYCN signatures in fluorite from the ABB and the FCB reflect geochemical variability due to adsorption processes and intrinsic crystallographic controls and imply that they are genetically related. Two petrographically and geochemically distinct generations are observed: Fluorite I—light SEM shades, relatively enriched in LREE; Fluorite II—darker SEM shades, comparatively depleted LREE, slightly higher HREE concentrations. These fluorite generations represent zoned (or cyclical) growth within a single progressive hydrothermal event and do not reflect a secondary remobilization process. We demonstrate that increasing Tb/La ratios and decreasing La/Ho ratios can be the result of continuous zoned growth during a single mineralizing event, with significant compositional variations on a micron-scale. This has implications for the interpretation of such trends and hence the inferred genetic evolution of fluorite that displays such geochemical patterns. The complex micro-scale intergrowth of these generations stresses the need for detailed petrographic investigations when geochemical data are collected and interpreted for mineral exploration.<br
Keywords: Remobilization; Trace elements; North German Basin; Rare earth elements; Zoned growth; Hydrothermal veins; Fluorite

Rhodolith beds (Corallinales, Rhodophyta) and their physical and biological environment at 80°31'N in Nordkappbukta (Nordaustlandet, Svalbard Archipelago, Norway) - Teichert, Sebastian; Woelkerling, William; Rüggeberg, Andres; Wisshak, Max; Piepenburg, Dieter; Meyerhöfer, Michael; Form, Armin; Büdenbender, Jan; Freiwald, André (Phycologia, 2012)
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LP.rhodol
Keywords: Lithothamnion glaciale; Nordkappbukta; Phymatolithon tenue; polar carbonate factory; rhodolith community; Svalbard

Rietveld structure and in vitro analysis on the influence of Magnesium in Biphasic (Hydroxyapatite and beta-Tricalcium phosphate) mixtures - Kannan, Sanjeevi; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen; Rebelo, Avito; Valério, Patrícia; da Fonte Ferreira, José Maria (Journal of Biomedical Materials Research Part B-Applied Biomaterials, 2009)
The structure of two different Mg-substituted biphasic (HAP and β-TCP) mixtures along with the biphasic mixtures without substituted Mg2+ was investigated using Rietveld refinement technique. The substituted Mg 2+ was found in the β-TCP phase and its influence on the composition has led to an increase in HAP content of Mg-containing biphasic mixtures when compared with the HAP content detected in pure biphasic mixtures. The refined structural parameters of Ca10(PO4) 6(OH)2 and β-Ca3(PO4) 2 confirmed that all the investigated compositions have crystallized in the corresponding hexagonal (space group P63/m) and rhombohedral (space group R3c) structures. The substitution of lower sized magnesium was found preferentially incorporated at the sixfold-coordinated Ca (5) site of β-TCP, which is due to the strong Ca (5)·O interaction among all the five different Ca sites of β-Ca3(PO4)2. The in vitro tests using primary culture of osteoblasts showed that all the tested samples are biocompatible and promising materials for in vivo studies. © 2008 Wiley Periodicals, Inc.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.rietve
Keywords: β-tricalcium phosphate; Biphasic mixtures; Hydroxyapatite; In vitro tests; Magnesium; Rietveld

Riffdiversität in der Erdgeschichte - Fossilbericht und Interpretationen. - Kießling, Wolfgang (Biodiversitätsforschung - Die Entschlüsselung der Artenvielfalt in Raum und Zeit., 2003)
Keywords: Riffe; Biodiversität; Riffevolution; Geobiologie

Rifting of the oceanic Azores Plateau with episodic volcanic activity - Storch, Bettina; Haase, Karsten; Romer, René; Beier, Christoph; Koppers, A. A.P. (Scientific Reports, 2020)
Extension of the Azores Plateau along the Terceira Rift exposes a lava sequence on the steep northern flank of the Hirondelle Basin. Unlike typical tholeiitic basalts of oceanic plateaus, the 1.2 km vertical submarine stratigraphic profile reveals two successive compositionally distinct basanitic to alkali basaltic eruptive units. The lower unit is volumetrically more extensive with 1060 m of the crustal profile forming between 2.02 and 1.66 Ma, followed by a second unit erupting the uppermost 30 m of lavas in 100 kyrs. The age of 1.56 Ma of the youngest in-situ sample at the top of the profile implies that the 35 km-wide Hirondelle Basin opened after this time along normal faults. This rifting phase was followed by alkaline volcanism at D. João de Castro seamount in the basin center indicating episodic volcanic activity along the Terceira Rift. The mantle source compositions of the two lava units change towards less radiogenic Nd, Hf, and Pb isotope ratios. A change to less SiO2-undersaturated magmas may indicate increasing degrees of partial melting beneath D. João de Castro seamount, possibly caused by lithospheric thinning within the past 1.5 million years. Our results suggest that rifting of oceanic lithosphere alternates between magmatically and tectonically dominated phases.
CRIS-Team Scopus Importer:2020-11-20

Rift–plume interaction reveals multiple generations of recycled oceanic crust in Azores lavas - Béguelin, Paul; Bizimis, Michael; Beier, Christoph; Turner, Simon (Geochimica Et Cosmochimica Acta, 2017)
Keywords: Azores; Hf isotopes; HIMU; Recycled oceanic crust; Triple ridge junction

River-fed wetland palaeovegetation and palaeoecology at the HWK W site, Bed I, Olduvai Gorge - Albert, R. M.; Bamford, M. K.; Stanistreet, I. G.; Stollhofen, Harald; Rivera-Rondón, Carlos A.; Njau, J. K.; Blumenschine, R. J. (Review of Palaeobotany and Palynology, 2018)
Palaeolandscape studies are an essential tool for understanding adaptation and use of plant- and water-related affordances by hominins. A number of high-resolution palaeolandscape analyses have been carried out at Olduvai Gorge (northern Tanzania) over the last two decades but none have focused on the Tuff ID-IE stratigraphic interval (1.83–1.84 Ma). At locality HWK W, this interval presents earthy facies, including siliceous earth, earthy claystone, sandy earth, and earthy sandstone facies varieties, which are rare for Bed I. These facies have been interpreted at other stratigraphic levels to represent densely vegetated wetlands. Additionally, the HWK W site has yielded quantities of fossil bone and tools eroding to the surface. Within the Tuff ID-IE interval, and during regression periods of Palaeolake Olduvai, fluvial and wetland facies were deposited. During this period, the phytoliths and plant macrofossils show that the vegetation was dominated by palms, associated with a mix of C3 and C4 grasses as well as sedges. The variation in phytolith types within these facies implies a locally diverse palaeoenvironmentalmicro-mosaic, with stacked transgressive sequences, varying from vegetated fluvial channels to vegetated levées and then backswamp subenvironments. Diatoms are particularly rich at Trench T155 and are associated with sponge spicules, indicating the presence of freshwater palaeowetlands with clear water. The extensive diatom valve fragmentation and the differences among trenches suggest that the diatom depositional environment was a heterogeneous river-fed palaeowetland or a vegetated fluvial channel affected by periodic droughts. A diverse fauna was recovered, comprising autochthonous hippopotamus and crocodile elements as well as herbivores drawn to the freshwater resource. Oldowan lithic artifacts were also recovered and some bone was processed through percussion and cutting by early hominins, likely Homo habilis. Overall, the first landscape reconstruction undertaken at HWK W locality during the Tuff ID-IE interval shows a dynamic and richly vegetated area that would have provided hominins with fresh water, scavengeable carcasses, aswell aswith edible plant affordances (palmfruits, starch-rich rhizomes fromsedges and Typha). The presence of palms suggests the area supported a diversity of trees, affording hominins refuge from predators.<br
Keywords: Hominins; Macroplant fossils; Diatoms; Tuff ID-IE interval palaeofacies; Paleovegetation; Phytoliths

Riverine Carbon Cycle - Barth, Johannes; et al. (Journal of the Czech Geological Society, 1997)

Riverine carbon dioxide evasion along a high-relief watercourse derived from seasonal dynamics of the water-atmosphere gas exchange - Juhlke, Tobias; van Geldern, Robert; Huneau, F.; Garel, E.; Santoni, S.; Hemmerle, H.; Barth, Johannes (Science of the Total Environment, 2019)
Keywords: Western Mediterranean; Stable isotopes; Carbon dioxide degassing; Dissolved inorganic carbon; Carbon cycle

River recharge versus O2 supply from the unsaturated zone in shallow riparian groundwater: A case study from the Selke River (Germany) - Mader, Michael; Roberts, André Michael; Porst, David; Schmidt, Christian; Trauth, Nico; van Geldern, Robert; Barth, Johannes (Science of the Total Environment, 2018)
Besides gas-water-exchange in surface waters, respiratory consumption of dissolved oxygen (DO) in adjacent riparian groundwater may trigger the addition of so far hardly explored sources from the unsaturated zone. These processes also systematically influence stable isotope ratios of DO and were investigated together with Cl− as a conservative tracer for water mixing in a near-river riparian groundwater system. The study focused on a losing stream section of the Selke River at the foot of the Harz Mountains (Germany). The study area exposed steep DO gradients between the stream water and riparian groundwater between April 2016 and May 2017. Our results indicated dominant influences of microbial community respiration with observed DO concentration gradients. These observations can be explained by DO from the river that is subject to fractionation by microbial respiration with a typical fractionation factor (αr) of 0.982. However, with such respiration dominance, we expected a simultaneous enrichment of δ18ODO towards values that are more positive than the well-known atmospheric O2 signal of +23.9‰ versus the Vienna Standard Mean Ocean Water standard (VSMOW). Surprisingly, our measurements revealed much lower δ18ODO values between +22‰ and +18‰ in the near-river groundwater. Mass balance calculations revealed that the DO pool in the shallow and unconfined aquifer receives contributions of up to about 80% by diffusion of oxygen from the vadose zone with a distinctly lower isotope value than the one of the atmosphere. This finding about additional oxygen sources from the unsaturated zone has numerous ramifications for oxygen related processes in near-river environments including the oxidation of pollutants, nutrients and ecosystem health.
Keywords: Riparian zone; Dissolved oxygen; Stable isotopes; Diffusion; Vadose zone

Rivers of North-Rhine Westphalia revisited: Tracing changes in river chemistry - Stoegbauer, Andrea; Strauss, Harald; Arndt, Julia; Marek, Victoria; Einsiedl, Florian; van Geldern, Robert (Applied Geochemistry, 2008)

Roadian-Wordian (Middle Permian) Conodont Biostratigraphy, Sedimentary Facies and Paleotemperature Evolution at the Shuixiakou Section, Xikou Area, Southeastern Qinling Region, China - Wu, Baojin; Li, Hanxiao; Joachimski, Michael; Wignall, Paul B.; Jiang, Haishui; Yan, Jiaxin; Wang, Lina; Wu, Xianlang; Lai, Xulong (Journal of Earth Science, 2021)
Focusing on the Shuixiakou Section (Xikou area, Zhen’an County, Shaanxi Province, southeastern Qinling region, China), the Roadian-Wordian conodonts are investigated. More than 2 000 conodont elements including 6 genera and 14 species have been obtained. Based on these materials, the Guadalupian Jinogondolella nankingensis and J. aserrata zones have been recognized. The Roadian-Wordian boundary is tentatively defined by the first occurrence of J. aserrata in the lower part of Unit III in the Shuixiakou Formation. The sedimentary succession of Xikou area records similar sea-level changes to those observed in Laibin area (South China). The 40 m-thick bioclastic limestone of Unit IV in this section can be correlated with the reefs of Bed 114 in Laibin area. A temperature drop indicated by δ18Oapatite values suggests this Wordian interval coincides with a period of glaciation and global regression.<br
Keywords: biostratigraphic framework; sea-level change; paleotemperature; Roadian-Wordian boundary; Shuixiakou Section

Robust landslide susceptibility analysis by combination of frequency ratio, heuristic GIS-methods and ground truth evaluation for a mountainous study area with poor data availability in the Three Gorges Reservoir area, PR China - Schleier, Markus; Bi, Renneng; Ehret, Dominik; Xiang, Wei; Rohn, Joachim (Environmental Earth Sciences, 2014)
Keywords: Frequency ratio analysis; Geographical Information System (GIS); Ground truth; Landslide susceptibility; Performance evaluation; Three Gorges Reservoir

Rock avalanches in a changing landscape following the melt down of the scandinavian ice sheet, Norway - Schleier, Markus; Hermanns, Reginald L.; Rohn, Joachim (Springer International Publishing, 2017)
Keywords: Innerdalen and innfjorddalen; Rock avalanche; Post-glacial isostatic rebound; Supraglacial rock avalanche; Subaqueous rock avalanche; Western Norway

Rockfall at Proglacial Rockwalls-A Case Study from the Kaunertal, Austria - Vehling, Lucas; Rohn, Joachim; Moser, Michael (Geomorphology of Proglacial Systems: Landform and Sediment Dynamics in Recently Deglaciated Alpine Landscapes, 2019)
Since the Little Ice Age, high alpine regions have faced rapid glacier melting that has contributed to enhanced rockfall activity at recently deglaciated rockwalls. At the Gepatschferner, Kaunertal (Austria), rockfall activity has been quantified for the past several years using rockfall collector nets, `natural' rockfall traps and multi-temporal LiDAR. Toppling and sliding activity of large unstable rock blocks, considered as precursors of rockfalls, were monitored by steel tape measurements and electrical crackmeters. The highest rockfall activity was measured at recently deglaciated rockwalls with low rock mass quality, where rockwall back-weathering rates locally exceeded 10 mm/a. Those rates are among the highest ever published. 108 mid- and high-magnitude rockfalls with volumes between 100 and 30,000 m(3) were released between 2006 and 2012. Their scars are clustered in the proglacial high-altitude parts of the Kaunertal. As well, rockwall activity was concentrated in the autumn and winter months.
CRIS-Team WoS Importer:2021-10-18

Rocks, fabrics and magnetic anisotropy: An introduction to the issue in honour of František Hrouda - Mamtani, Manish A.; Chadima, Martin; de Wall, Helga; Greiling, Reinhard O. (International Journal of Earth Sciences, 2012)

Rock Thermal Conductivity as Key Parameter for Geothermal Numerical Models - Di Sipio, Eloisa; Chiesa, Sergio; Destro, Elisa; Galgaro, Antonio; Giaretta, Aurelio; Gola, Gianluca; Manzella, Adele (Energy Procedia, 2013)
Keywords: thermal conductivity; geothermal energy; low enthalpy resources; thermal conductivity analyzer

Role of seafloor production versus continental basalt weathering in Middle to Late Ordovician seawater 87Sr/86Sr and climate - Avila, Teresa D.; Saltzman, Matthew R.; Adiatma, Y. Datu; Joachimski, Michael; Griffith, Elizabeth M.; Olesik, John W. (Earth and Planetary Science Letters, 2022)
The global climate of the Ordovician Period (486.9 to 443.1 Ma) is characterized by cooling that culminated in the Hirnantian glaciation. Chemical weathering of Ca- and Mg-bearing silicate minerals and the subsequent trapping of carbon in marine carbonates act as a sink for atmospheric CO2 on multi-million-year time scales, with basaltic rocks consuming CO2 at a greater rate than rocks of granitic composition. The oceanic Sr isotope ratio (87Sr/86Sr) can act as a geochemical proxy for the relative proportion of basaltic versus granitic weathering. Oxygen isotopes (O) act as a proxy for paleotemperature and ice volume, providing a useful complement to 87Sr/86Sr in studies of ancient climate. Previous studies have reported stepwise cooling (increasing O) during the Middle to Late Ordovician. Combined with Sr and C cycle models, this has led to the hypothesis that continental silicate weathering of mafic material drove Ordovician cooling (e.g., the Taconic Orogeny). However, Sr and C cycle models have not accounted for an apparent rise in sea level and seafloor production in the Middle Ordovician (Darriwilian), which would increase the hydrothermal Sr flux as well as degassing along continental volcanic arcs. Furthermore, some Ordovician studies contain temporal uncertainty between 87Sr/86Sr and O curves if they are not based on paired analyses, which can obscure the relationship between silicate weathering and cooling. Here, we present new paired 87Sr/86Sr and O data from conodont apatite and integrate this with both a deterministic (forward) and stochastic (reverse) modeling approach to argue that increased hydrothermal weathering played a role in driving marine 87Sr/86Sr, specifically an inflection occurring in the Pygoda serra conodont zone of the mid-Darriwilian Stage (∼ 460.9 Ma ± 1 My). This 87Sr/86Sr inflection is accompanied by an increase in O, consistent with climate cooling. Clarifying the role of seafloor production for marine 87Sr/86Sr and the implications for Ordovician cooling allows for a more nuanced understanding of the factors that drive multi-million-year<br
Keywords: Ordovician; geochemistry; paleoclimatology; silicate weathering; conodont; strontium

Roman coarse ware from Bavaria, Austria and Northern Italy - Joachimski, Michael; et al. (Hyperfine Interactions, 2004)
This interdisciplinary study focuses on a specific type of Roman coarse ware that was widely distributed in Bavaria, Austria and northern Italy during the 1st half of the 1st century AD. Various physical methods were applied to study the provenance of this characteristic marble tempered blackware and to assess its production techniques. The blackware found in large numbers on the Auerberg and at other sites in southern Germany can be identified as imported from East Tyrol, Austria.
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.LG.romanc
Keywords: gas chromatography; Mössbauer spectroscopy; neutron activation analysis; production techniques; provenance studies; Roman coarse ware; stable isotope analysis; thin section microscopy

Römische Keramik mit Marmormagerung: Herkunftsbestimmung mit Hilfe von stabilen Isotopen (Auerbergtöpfe aus Süddeutschland). - Flügel, C.; Joachimski, Michael; Flügel, Erik (Archäologisches Korrespondenzblatt, 1997)
UnivIS-Import:2015-03-05:Pub.1997.nat.dgeo.IGM.LG.rmisch

Röntgenographische Phasenanalyse von eisenreichen Tonerdezementklinkern - Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde (2000)
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LM.rntgen

Rostrum size differences between Toarcian belemnite battlefields - Costa Rita, Patrícia; de Baets, Kenneth; Schlott, Martina (FOSSIL RECORD, 2018)
Body size changes have been reported across crisis intervals. Belemnites – now considered extinct stem-decabrachians – have rarely been investigated for this purpose, and the few studies have resulted in ambiguous outcomes. Here we investigate two Toarcian belemnite accumulations in southern Germany from a morphometric point of view with the support of computed tomography data. The aim of this study is to test whether a difference in size can be observed between the rostra of the two studied samples, from individual lineage to community, and which proxy is more reliable. A significant decrease in median size from the Early Toarcian (Dactylioceras tenuicostatum Zone) to the Middle Toarcian (Haugia variabilis Zone) is recognized. This is observed at the community level of organization, considering the whole assemblage, but also within Passaloteuthis–Acrocoelites lineage, at the genus level. It is also demonstrated that diameter-based measurements or maximum preserved length are not reliable proxies for size, and therefore apical length or three-dimensional approximations, such as the geometric mean or the post-phragmocone volume, are more advisable. This is especially important when comparing specimens with markedly different rostrum shapes. Further studies are, however, still necessary to disentangle the mechanisms behind the reduction in rostrum size within the Toarcian and their putative environmental cause

Rotliegend im Saar-Nahe-Becken, am Taunus-Südrand und im nördlichen Rheingraben - Boy, Jürgen A.; Haneke, Jost; Kowalczyk, Gotthard; Lorenz, Volker; Schindler, Thomas; Stollhofen, Harald; Thum, Hubert (Stratigraphie von Deutschland X. Rotliegend. Teil I: Innervariscische Becken., 2012)
UnivIS-Import:2015-04-20:Pub.2012.nat.dgeo.IGM.LG.dasrot

Routine analysis by high precision gas chromatography/mass selective detector/isotope ratio mass spectrometry to 0.1 Parts per mil - Barth, Johannes; Hall, James; Kalin, Robert, M. (Rapid Communications in Mass Spectrometry, 1999)

Routine (an)isotropic crystallite size analysis in the double-Voigt approximation done right? - Ectors, Dominique; Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (Powder Diffraction, 2017)
In this study, the application of (an)isotropic size determination using a recently proposed model for the double-Voigt approach is demonstrated and validated against line profile simulations using the Whole Powder Pattern Modelling approach. The fitting of simulated line profiles demonstrates that the attained crystallite sizes and morphologies are in very reasonable agreement with the simulated values and thus demonstrate that even in routine application scenarios credible size and morphology information can be obtained using the double-Voigt approximation. The aim of this contribution is to provide a comprehensive introduction to the problem, address the practical application of the developed model, and discuss the accuracy of the double-Voigt approach and derived size parameters. Mathematical formulations for the visualization of modeled morphologies, supporting the application of the recently developed macros, are additionally provide
Keywords: anisotropic crystallite size; double-Voigt; Rietveld; size–strain; TOPAS

Saalfrank-type Fe2L3 host-guest complexes - Prediction of ion selectivity by quantum chemical calculations VII - Begel, Svetlana; Scheurer, Andreas; Puchta, Ralph (Journal of Coordination Chemistry, 2015)
Keywords: DFT; Metallocryptates; Metallocryptands; Selective ion complexation; Proton affinity

Salinity contrast in the US Midcontinent Sea during Pennsylvanian glacio-eustatic highstands: Evidence from conodont apatite δ 18O - Joachimski, Michael; Lambert, Lance; Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 2015)
Pennsylvanian phosphatic black shales are widely interpreted to have been deposited in waters deep enough to produce a pycnocline that would have developed as a consequence of increased riverine runoff into the largely landlocked North American Midcontinent Sea during the more humid interglacial intervals of the Late Palaeozoic Ice Age. We tested whether a gradient in surface water salinity existed in the North American Midcontinent Sea during times of maximum flooding by analyzing oxygen isotopes of conodont apatite from correlative Pennsylvanian black shales of the Midland, Midcontinent, Illinois and Appalachian basins. In the Midland and Midcontinent basins, average δ18O values for conodonts from the Oakley (middle Desmoinesian/upper Moscovian), Hushpuckney (lower Missourian, lower Kasimovian) and Heebner black shales (lower Virgilian/lower Gzehlian) are 18.8±0.3‰, 19.1±0.2‰, and 18.9±0.1‰, respectively. Oxygen isotope ratios of conodonts from the Nuyaka Creek black shale (uppermost Desmoinesian/upper Moscovian) of the Midcontinent Basin are 19.8±0.3‰, and thus significantly higher in comparison to the other black shales. These higher values support previous interpretations that the Lost Branch is a minor cyclothem, with south polar regions having been less deglaciated than during the interglacial phases of the more widespread major cyclothems. Conodonts from Oakley shale equivalents from Ohio and Pennsylvania are depleted in 18O on average by 2.5‰ in comparison to conodonts from the Midcontinent Basin. This pattern is also evident for conodonts from the Heebner and Hushpuckney shales, although conodonts from the Appalachian Basin show only a 0.4-0.7‰ depletion in 18O compared to conodonts from the Midcontinent Basin. The differences in δ18O are interpreted as reflecting primarily salinity, assuming that temperature was relatively constant across the palaeotropical Midcontinent Sea.Lower salinities in the Appalachian Basin and a significant salinity gradient in the Midcontinent Sea were reconstructed for the Desmoinesian Oakley shale, supporting the idea that freshwater discharge resulted in a salinity-stratified water column during times of "everwet" tropical palaeoclimate, at least in the eastern part of the epeiric sea. However, the salinity gradient is considerably reduced during the subsequent Missourian and Virgilian periodically dry interglacial periods (Hushpuckney and Heebner shales). This suggests that surface waters in the Midcontinent Sea were not significantly influenced by continental runoff and calls into question whether a halocline was necessary for the formation of phosphatic core shales.
Keywords: Conodont; Oxygen isotopes; Pennsylvanian; Salinity; US Midcontinent

Salinization Processes in the Venetian Coastal Plain (Italy): A General Overview - Di Sipio, Eloisa; Re, Viviana; Cavaleri, Nicoletta; Galgaro, Antonio (Procedia Earth and Planetary Science, 2013)
Keywords: groundwater; salinization; geochemical-isotopic analyses; geoelectrical soundings; Venice coastal plain

Salt kinematics and regional tectonics across a Permian gas field: a case study from East Frisia, NW Germany. - Vackiner, Anna Alexandra; Antrett, Philipp; Strozyk, Frank; Back, Stefan; Kukla, Peter; Stollhofen, Harald (International Journal of Earth Sciences, 2013)
This study presents a reconstruction of the tectonic history of an Upper Rotliegend tight gas field in Northern Germany. Tectonism of the greater study area was influenced by multiple phases of salt movement, which produced a variety of salt-related structural features such as salt walls, salt diapirs as well as salt glaciers (namakiers). A sequential 2D retro-deformation and stratal backstripping methodology was used to differentiate mechanisms inducing salt movement and to discuss their relation to regional tectonics. The quantitative geometric restoration included sedimentary balancing, decompaction, fault-related deformation, salt movement, thermal subsidence, and isostasy to unravel the post-depositional tectonic overprint of the Rotliegend reservoir rock. The results of this study indicate that reactive salt diapirism started during an Early Triassic interval of thin-skinned extensional tectonics, followed by an active diapirism stage with an overburden salt piercement in the Late Triassic, and finally a period of intensive salt surface extrusion and the formation of salt glaciers (namakiers) in Late Triassic and Jurassic times. Since the Early Cretaceous, salt in the study area has been rising by passive diapirism. © 2013 Springer-Verlag Berlin Heidelberg.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.saltki
Keywords: Backstripping; Salt namakiers/glaciers; Salt tectonics; Sequential restoration; Tectonics and sedimentation

Salt water intrusion in the shallow aquifers of Venice lagoon mainland - Di Sipio, Eloisa; Re, Viviana; Cavaleri, Nicoletta (Rendiconti Online Societa Geologica Italiana, 2013)
Keywords: Geochemical-isotopic analyses; groundwater; salinization; Venice coastal Plain

Sample preparation effects on illite "crystallinity" measurement; gradation and particle orientation. - Krumm, Stefan; Buggisch, Werner (Journal of Metamorphic Geology, 1991)
Specimen thickness is the main experimental factor controlling the results of illite crystallinity (IC) or crystallite size measurements on sedimentation slides. Orientation effects control the measured peak intensity. A plateau with constant peak breadths is observed if thin slides of well ordered, platy illites are used. A similar plateau can be recognized for thick preparations of specimens from less ordered materials, but not from well ordered ones. Therefore, it is suggested that IC is determined on very thin sedimentation slides with a thickness of 0.25 mg/cm2 or less. -from Authors
UnivIS-Import:2015-03-05:Pub.1991.nat.dgeo.IGM.LG.sample

Sampling biases obscure the early diversification of the largest living vertebrate group - Henderson, Struan; Dunne, Emma; Giles, Sam (Proceedings of the Royal Society of London, Series B: Biological Sciences, 2022)
Extant ray-finned fishes (Actinopterygii) dominate marine and freshwater environments, yet spatio-temporal diversity dynamics following their origin in the Palaeozoic are poorly understood. Previous studies investigate face-value patterns of richness, with only qualitative assessment of biases acting on the Palaeozoic actinopterygian fossil record. Here, we investigate palaeogeographic trends, reconstruct local richness and apply richness estimation techniques to a recently assembled occurrence database for Palaeozoic ray-finned fishes. We identify substantial fossil record biases, such as geographical bias in sampling centred around Europe and North America. Similarly, estimates of diversity are skewed by extreme unevenness in the occurrence distributions, reflecting historical biases in sampling and taxonomic practices, to the extent that evenness has an overriding effect on diversity estimates. Other than a genuine rise in diversity in the Tournaisian following the end-Devonian mass extinction, diversity estimates for Palaeozoic actinopterygians appear to lack biological signal, are heavily biased and are highly dependent on sampling. Increased sampling of poorly represented regions and expanding sampling beyond the literature to include museum collection data will be critical in obtaining accurate estimates of Palaeozoic actinopterygian diversity. In conjunction, applying diversity estimation techniques to well-sampled regional subsets of the 'global' dataset may identify accurate local diversity trends.
CRIS-Team Scopus Importer:2022-10-28
Keywords: Actinopterygii; diversity; fossil record bias; Palaeozoic; sampling standardization