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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

ITER Project: Improving Thermal Efficiency of hoRizontal ground heat exchangers - Di Sipio, Eloisa; Bertermann, David (ESOF CONFERENCE MSCA Satellite Event, 2016)

ITER Project: Improving Thermal Efficiency of hoRizontal ground heat exchangers - Di Sipio, Eloisa; Bertermann, David (Book of Abstracts, General Assembly of the Marie Curie Alumni Association, 2017)

ITER Project: Improving Thermal Efficiency of hoRizontal ground heat exchangers - Di Sipio, Eloisa; Bertermann, David (Book of Abstracts, General Assembly of the Marie Curie Alumni Association, 2016)

Jaws of a large belemnite and an ammonite from the Aalenian (Middle Jurassic) of Switzerland - Klug, Christian; Etter, Walter; Hoffmann, René; Fuchs, Dirk; de Baets, Kenneth (Swiss Journal of Palaeontology, 2020)
Although belemnite rostra can be quite abundant in Jurassic and Cretaceous strata, the record of belemnite jaws was limited to a few specimens from Germany and Russia. Here, we describe and figure three cephalopod jaws from the Middle Jurassic Opalinus Clay of northern Switzerland. Although flattened, the carbonaceous fossils display enough morphological information to rule out an ammonoid, nautiloid or octobrachian origin of the two larger jaws. Their similarities to belemnite jaws from Germany and Russia conforms with our interpretation of these specimens as belemnite jaws. Based on their rather large size, we tentatively assign these two jaws to the megateuthidid Acrocoelites conoideus. The third jaw is a rather small upper jaw of an ammonoid. Since Leioceras opalinum is by far the most common ammonite in this unit in northern Switzerland, we tentatively suggest that the upper jaw belongs to this species.
CRIS-Team Scopus Importer:2020-09-11
Keywords: Body size; Cephalopoda; Graphoceratidae; Megateuthididae; Mouthparts; Opalinus clay

Jurassic shift from abiotic to biotic control on marine ecological success - Eichenseer, Kilian; Balthasar, Uwe; Smart, Christopher W.; Stander, Julian; Haaga, Kristian A.; Kießling, Wolfgang (Nature Geoscience, 2019)
Environmental change and biotic interactions both govern the evolution of the biosphere, but the relative importance of these drivers over geological time remains largely unknown. Previous work suggests that, unlike environmental parameters, diversity dynamics differ profoundly between the Palaeozoic and post-Palaeozoic eras. Here we use the fossil record to test the hypothesis that the influence of ocean chemistry and climate on the ecological success of marine calcifiers decreased throughout the Phanerozoic eon. Marine calcifiers build skeletons of calcite or aragonite, and the precipitation of these calcium carbonate polymorphs is governed by the magnesium-to-calcium ratio and temperature in abiotic systems. We developed an environmental forcing model based on secular changes of ocean chemistry and temperature and assessed how well the model predicts the proliferation of skeletal taxa with respect to calcium carbonate polymorphs. Abiotic forcing governs the ecological success of aragonitic calcifiers from the Ordovician to the Middle Jurassic, but not thereafter. This regime shift coincides with the proliferation of calcareous plankton in the mid-Mesozoic. The deposition of biomineralizing plankton on the ocean floor buffers CO2 excursions and stabilizes Earth’s biochemical cycle, and thus mitigates the evolutionary impact of environmental change on the marine biota.
CRIS-Team Scopus Importer:2019-07-16

Kalk-Mergel-Wechselfolgen - Ein Blick hinter die Kulissen - Munnecke, Axel (Geowissenschaftliche Mitteilungen, 2016)
Keywords: Kalk-Mergel-Wechselfolgen; Kalk; Mergel; Diagenese; Kompaktion

Kalorimetrische und röntgenographische Untersuchungen zur Hydratation von Schnellzementen aus Portland- und Calciumaluminatzement - Götz-Neunhoeffer, Friedlinde; Neubauer, Jürgen (GDCh-Monographie Tagung Bauchemie, 2006)
UnivIS-Import:2015-04-02:Pub.2006.nat.dgeo.IGM.LM.kalori

Karoo Synrift-Sedimentation und ihre tektonische Kontrolle am entstehenden Kontinentalrand Namibias. - Stollhofen, Harald (Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 1999)
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LG.karoos

Karoo unconformities in NW Namibia and their tectonic implications. - Wanke, Ansgar; Stollhofen, Harald; Stanistreet, Ian G.; Lorenz, Volker (Communications - Geological Survey of Namibia, 2000)
The Karoo-Etendeka depositories in northwestern Namibia can be subdivided into (l) a Carboniferous-Permian, (2) a Triassic-Jurassic and (3) a Cretaceous megasequence, recording successive extensional periods, separated by time-stratigraphic gaps. Close to the present-day Atlantic coastline the Karoo Supergroup is only represented by the Permian succession in the Huab area. This is disconformably overlain by the Lower Cretaceous Etendeka Group. Further east, the Karoo succession becomes successively’ more complete, but correlation with the main Karoo Basin in South Africa and the Brazilian Paraná Basin indicates major gaps in the sedimentary record. The gaps can be attributed to the combined effects of the long-lived South Atlantic rift evolution and orogenic pulses derived from the Samfrau active margin.
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LG.karoou

Keeping to the set path enhanced storage stability for dry-mix mortars based on calcium aluminate - Estival, Jaques; Taquet, Pascal; Götz-Neunhoeffer, Friedlinde (European Coatings Journal, 2012)
Storage under high humidity can adversely affect the properties of dry mix mortars containing hydraulic binders. A new functionalised Calcium Aluminate Cement (CAC) has been developed with the aim of stabilising mortar reactivity during storage. Both setting kinetics and other properties such as shrinkage, porosity and linear size variations were found more robust over storage in humid conditions.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LM.keepin

Keratose sponges in ancient carbonates – A problem of interpretation - Neuweiler, Fritz; Kershaw, Stephen; Boulvain, Frédéric; Matysik, Michał; Sendino, Consuelo; McMenamin, Mark; Munnecke, Axel (Sedimentology, 2022)
Reports of diverse vermiform and peloidal structures in Neoproterozoic to Mesozoic open marine to peritidal carbonates include cases interpreted to be keratose sponges. However, living keratose sponges have elaborate, highly elastic skeletons of spongin (a mesoscopic end-member of a hierarchical assemblage of collagenous structures) lacking spicules, thus have poor preservation potential in contrast to the more easily fossilized spicule-bearing sponges. Such interpreted fossil keratose sponges comprise diverse layered, network, amalgamated, granular and variegated microfabrics of narrow curved, branching, vesicular–cellular to irregular areas of calcite cement, thought to represent former spongin, embedded in microcrystalline to peloidal carbonate. Interpreted keratose sponges are presented in publications almost entirely in two-dimensional (thin section) studies, usually displayed normal to bedding, lacking mesoscopic three-dimensional views in support of a sponge body fossil. For these structures to be keratose sponges critically requires conversion of the spongin skeleton into the calcite cement component, under shallow-burial conditions and this must have occurred prior to compaction. However, there is no robust petrographic–geochemical evidence that the fine-grained carbonate component originated from sponge mummification (automicritic body fossils via calcification of structural tissue components) because in the majority of cases the fine-grained component is homogenous and thus likely to be deposited sediment. Thus, despite numerous studies, verification of fossil keratose sponges is lacking. Although some may be sponges, all can be otherwise explained. Alternatives include: (i) meiofaunal activity; (ii) layered microbial (spongiostromate) accretion; (iii) sedimentary peloidal to clotted micrites; (iv) fluid escape and capture resulting in bird's eye to vuggy porosities; and (v) moulds of siliceous sponge spicules. Uncertainty of keratose sponge identification is fundamental and far-reaching for understanding: (i) microfacies and diagenesis where they occur; (ii) fossil assemblages; and (iii) wider aspects of origins of animal clades, sponge ecology, evolution and the systemic recovery from mass extinctions. Thus, alternative explanations must be considered.
CRIS-Team Scopus Importer:2022-12-23
Keywords: Automicrite; metazoan evolution; microfacies analysis; mummification; sponge taphonomy

Kinematics and mechanism of motion of the profound Cuolm da Vi instability at Graubünden, Switzerland Kinematik und Bewegungsmechanismus der Tiefgründigen Instabilität Cuolm da Vi (Graubünden, Schweiz) - Moser, Michael; et al. (Bulletin fuer Angewandte Geologie, 2006)

Kinetic Interface Sensitive Tracers: Experimental Validation in a Two-Phase Flow Column Experiment. A Proof of Concept - Tatomir, Alexandru; De Vriendt, K.; Zhou, D.; Gao, H.; Duschl, Florian; Sun, F.; Licha, T.; Sauter, Martin (Water Resources Research, 2018)
Keywords: column experiment; fluid-fluid interfacial area; transient flow; kinetic interface sensitive tracers; multiphase flow

Kinetics, mechanism and density functional theory calculations on base hydrolysis of α-amino acid esters catalyzed by [Pd(AEMP)(H2O)2]2+ (AEMP = 2-(2-aminoethyl)-1-methylpyrrolidine) - Shoukry, Mohamed M.; Shehata, Mohamed R.; Ragab, Mona S.; Ćorćić, Dušan; Puchta, Ralph; van Eldik, Rudi (Reaction Kinetics Mechanisms and Catalysis, 2020)
Abstract: Pd(AEMP)Cl2 (AEMP = 2-(2-aminoethyl)-1-methylpyrrolidine) was synthesized and characterized by spectral and thermal measurements.[Pd(AEMP)(H2O)2]2+ reacts with amino acid esters (L) to form mixed ligand [Pd(AEMP)L]2+ complexes. The kinetics of the base hydrolysis of [Pd(AEMP)L]2+ was studied by a pH-stat technique and the corresponding rate constants are reported. The coordinated glycine methyl ester is hydrolyzed efficiently, whereas the coordinated methionine- and histidine- methyl esters undergo hydrolysis with a much lower catalytic activity. The catalytic effect is controlled by the mode of coordination of the ester to the Pd(II) complex. Possible mechanisms for these reactions are considered. Activation parameters were determined experimentally for the hydrolysis of the coordinated glycine methyl ester. DFT calculations (B3LYP/def2svp) were applied to gain further insight into the possible mechanism of the base hydrolysis of the amino acid esters. The calculations are discussed in reference to the reported experimental data. Graphic abstract: [Figure not available: see fulltext.].
CRIS-Team Scopus Importer:2020-02-25
Keywords: 2-(2-Aminoethyl)-1-methylpyrrolidine; Amino acid ester; Catalytic hydrolysis; DFT calculations; Pd(II); pH-stat technique

Klimawandel und Veränderung der Biodiversität in der Erdgeschichte. - Königshof, Peter; Suttner, Thomas J; Kießling, Wolfgang (Natur, Forschung, Museum, 2012)
Keywords: Climate change; Biodiversity; Evolution; Extinction

Krisen als Chance: Lernen aus der Evolution - Kießling, Wolfgang (Darwin meets Business, 2010)
Keywords: Extinctions; Biodiversity; Applied Paleobiology

KTB Oberpfalz - einige Ergebnisse der geowissenschaftlichen Bearbeitung - de Wall, Helga; et al. (Zentralblatt für Geologie und Paläontologie, Teil I, Geologie, 1994)
UnivIS-Import:2015-03-05:Pub.1994.nat.dgeo.IGM.c3tekt.ktbobe

Laboratory device to analyse the impact of soil properties on electrical and thermal conductivity - Bertermann, David; Schwarz, Hans (International Agrophysics, 2017)
Keywords: electrical resistivity; soil properties; thermal conductivity; Wenner array; geology; erneuerbare Energiequelle; Bodenkunde; geophysic

Laboratory Measurements of Gravel Thermal Conductivity: An Update Methodological Approach - Dalla Santa, Giorgia; Peron, Fabio; Galgaro, Antonio; Cultrera, Matteo; Bertermann, David; Müller, Johannes; Bernardi, Adriana (Energy Procedia, 2017)

Laboratory measurements of gravel thermal properties. A methodology proposal - Cultrera, Matteo; Peron, Fabio; Bison, Paolo; Dalla Santa, Giorgia; Bertermann, David; Müller, Johannes; Bernardi, Adriana; Galgaro, Antonio (Geophysical Research Abstracts Vol. 19, 2017)

Laborversuche zur Herstellung von Alinitzementen aus Müllverbrennungsrückständen - Oberste-Padtberg, Rüdiger; Neubauer, Jürgen (Wasser, Luft und Boden, 1989)
UnivIS-Import:2015-03-05:Pub.1989.nat.dgeo.IGM.LM.laborv

Lahar inundated, modified, and preserved 1.88 Ma early hominin (OH24 and OH56) Olduvai DK site - Stanistreet, Ian G.; Stollhofen, Harald; Njau, Jackson K.; Farrugia, Paul; Pante, Michael C.; Masao, Fidelis T.; Albert, Rosa Maria; Bamford, Marion (Journal of Human Evolution, 2018)
Archaeological excavations at the DK site in the eastern Olduvai Basin, Tanzania, age-bracketed between 1.88 Ma (Bed I Basalt) and 1.85 Ma (Tuff IB), record the oldest lahar inundation, modification, and preservation of a hominin “occupation” site yet identified. Our landscape approach reconstructs environments and processes at high resolution to explain the distribution and final preservation of archaeological materials at the DK site, where an early hominin (likely Homo habilis) assemblage of stone tools and bones, found close to hominin specimens OH24 and OH56, developed on an uneven heterogeneous surface that was rapidly inundated by a lahar and buried to a depth of 0.4-1.2 m (originally 1.0-2.4 m pre-compaction). The incoming intermediate to high viscosity mudflow selectively modified the original accumulation of “occupation debris,” so that it is no longer confined to the original surface. A dispersive debris “halo” was identified within the lahar deposit: debris is densest immediately above the site, but tails off until not present >150 m laterally. Voorhies indices and metrics derived from limb bones are used to define this dispersive halo spatially and might indicate a possible second assemblage to the east that is now eroded away. Based upon our new data and prior descriptions, two possibilities for the OH24 skull are suggested: it was either entrained by the mudflow from the DK surface and floated due to lower density toward its top, or it was deposited upon the solid top surface after its consolidation. Matrix adhering to material found in association with the parietals indicates that OH56 at least was relocated by the mudflow.
Keywords: Lahar mudflow; OH24; OH56; Olduvai Gorge Bed I; Pleistocene; Voorhies index

Lake conditions and detrital sources of Paleolake Olduvai, Tanzania, reconstructed using X-ray Diffraction analysis of cores - McHenry, Lindsay J.; Kodikara, Gayantha R.L.; Stanistreet, Ian G.; Stollhofen, Harald; Njau, Jackson K.; Schick, Kathy; Toth, Nicholas (Palaeogeography, Palaeoclimatology, Palaeoecology, 2020)
The Olduvai Basin of northern Tanzania contains well-known Pleistocene archaeological sites in a palaeoenvironmental setting of interfingering paleolake and volcanic fan deposits. This study documents the mineral assemblages, as determined qualitatively through bulk X-ray Diffraction (XRD) of systematically sampled lacustrine sediments from Olduvai Gorge Coring Project (OGCP) Cores 1A, 2A, and 3A, from about 45 m below the surface (mbs) to the base of all three cores. This interval includes fluvio-lacustrine sediments below and between two major progradations of Ngorongoro volcanic deposits recorded in Core 2A, and all of Olduvai Bed I and the lower part of Bed II in all three cores. Changes in mineral assemblage track changes in sediment sources and lake water chemistry. Abundant quartz indicates sediment sources derived from eroded Precambrian basement quartzite and gneiss exposures to the west, southwest, and north. In contrast, the presence of anorthoclase feldspar (sometimes associated with minor augite) indicates southerly and easterly sources, derived from the then active volcanoes (Ngorongoro, Olmoti) of the Ngorongoro Volcanic Highlands. The presence and relative abundance of specific zeolites provides information about Paleolake Olduvai's pH conditions and the relative activities of various dissolved cations (K+, Na+, Ca2+, Si) at the time of alteration, and the presence and abundance of authigenic K-feldspar indicates post-depositional exposure to saline-alkaline pore fluids. The mineral assemblages recorded in the cores reveal both large-scale trends in sediment composition over time, and smaller-scale changes related to fluctuating lake levels. In the lacustrine deposits near the base of Core 2A (interval NSF-1), analcime dominates the zeolite assemblage (with minor clinoptilolite), whereas carbonates and authigenic K-feldspar are rare. This interval is followed by more lacustrine deposits in which phillipsite and chabazite are the dominant zeolites (and analcime is absent). Lacustrine deposition was interrupted by the first of two pulses of coarse Ngorongoro volcaniclastic material (NVF-1). In the lacustrine interval between the two Ngorongoro volcanic pulses (NSF-2, recovered only in Core 2A), chabazite and erionite dominate the zeolite assemblage, carbonate and K-feldspar are rare, and analcime is absent, indicating less extreme saline-alkaline conditions and greater Ca2+ availability for zeolite formation. Volcanic glass is preserved, along with abundant zeolites, including phillipsite, chabazite, and erionite, in altered volcanic materials from the upper Ngorongoro volcanic pulse (NVF-2). In the lacustrine deposits of Lower Bed I (below the Bed I basalts but above NVF-2, only recovered in Core 3A), zeolites and K-feldspar are rare to absent, consistent with wetter conditions and fresher lake waters. Carbonates are ubiquitous throughout the lacustrine intervals of Beds I and II. In lacustrine deposits above the Bed I basalts (in Upper Bed I), phillipsite is the dominant zeolite, and quartz is rare. Alternating intervals of zeolite and K-feldspar-rich and poor sediments suggest variations between wetter and drier conditions throughout Upper Bed I and into Lower Bed II. Aragonite and associated dolomite in Bed I during the deposition of a claystone Mg-anomaly points to high magnesium concentrations and elevated Mg2+/Ca2+ ratios during that time. A major change between lowermost Bed II and overlying Bed II lacustrine sediments includes an abrupt increase in quartz coupled with an increase in the zeolite analcime, consistent with the onset of more saline-alkaline conditions, contemporaneous with overall drier conditions.
CRIS-Team Scopus Importer:2020-07-10
Keywords: East Africa; Mineral assemblage; Pleistocene; Saline-alkaline; Zeolites

Laminated carbonate deposits in Roman aqueducts: origin, processes and implications. - Suermelihindi, Guel; Passchier, Cees W.; Spoetl, Christoph; Kessener, Paul; Bestmann, Michel; Jacob, Dorrit E.; Baykan, Orhan N. (Sedimentology, 2013)
Carbonate deposits in Roman aqueducts of Patara and Aspendos (southern Turkey) were studied to analyse the nature of their regular layering. Optical microscopy and electron-backscattered diffraction results show an alternation of dense, coarsely crystalline, translucent laminae composed of bundles and fans of elongate calcite crystals with their c-axes parallel to the long axis, and porous, fine-grained laminae with crystals at near-random orientation. The δ18O and δ13C data show a strong cyclicity and anti-correlation, whereby high and low δ18O values correspond to dense columnar and porous fine-grained laminae, respectively. Geochemical analyses show similar cyclic changes in carbonate composition. Electron microprobe and laser ablation inductively coupled mass spectrometry analyses show that porous fine-grained laminae are enriched in elements associated with detrital material (Fe, Mg, K, Al and Si), whereas the dense columnar laminae are nearly pure calcite. The gradient in major and trace-element distribution, regular changes in crystal type and in oxygen and carbon-isotope composition from porous fine-grained to dense columnar laminae reflect changes in water chemistry, discharge, temperature and biological activity. Because of the strong bimodal cyclicity of the Mediterranean climate in southern Turkey, the observed laminae can be attributed to calcite deposition during the dry (porous fine-grained) and wet season (dense columnar), respectively. This observation implies that, with proper geochemical and microstructural control, lamination in carbonate deposits in Roman aqueducts can be used for relative dating of aqueduct construction and maintenance and to obtain data on external factors that influenced the aqueducts, such as palaeoclimate and natural hazards. Carbonate deposits in Roman aqueducts show properties of both flowstone speleothems and riverine fresh water tufa. As many aqueducts of nearly identical channel geometry are present in different climate zones and with different source water characteristics, they can be used as natural experiment setups to test and improve existing models of how laminated fresh water carbonates record climate on time scales ranging from seasonal to millennial. © 2012 The Authors. Journal compilation © 2012 International Association of Sedimentologists.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.c3tekt.lamina
Keywords: Calcareous sinter; Carbonate deposits; Layering; Roman aqueduct; Stable isotopes; Trace elements; Turkey

Landscape Distribution of Oldowan Stone Artifact Assemblages across the Fault Compartments of the Eastern Olduvai Lake Basin during Early Lowermost Bed II Times - Blumenschine, Robert J.; Masao, Fidelis T.; Stollhofen, Harald; Stanistreet, Ian G.; Bamford, Marion K.; Albert, Rosa M.; Njau, Jackson K.; Prassack, Kari A. (Journal of Human Evolution, 2012)
The density and composition of Oldowan stone artifact assemblages deposited during the first ca. 20,000 years of lowermost Bed II times show a recurrent pattern of variation across recognized synsedimentary faults that compartmentalized landscapes of the eastern Olduvai Lake Basin. When active, the faults created minor topographic relief. The upthrown fault footwalls accumulated assemblages with relatively high densities of artifacts, including types retaining potential usefulness, particularly volcanic flaked pieces, manuports, pounded pieces, and split cobbles. Values for these assemblage characteristics decline toward the lower-lying hangingwall of the fault compartments, accompanied by an increase in the proportionate weight of artifact assemblages comprising quartzite, particularly flaking shatter and potentially useful detached pieces. Values reverse once again at faults, either on the downthrown, hangingwall side or on the upthrown side. The patterns are stronger for the volcanic components of the artifact assemblages than for the quartzite components, reflecting the additional influence of distance from the local source on quartzite assemblage characteristics reported previously. The landscape distributions of artifact assemblages are consistent with a landscape-fault model in which minor fault-induced topographic relief at times created a mosaic of vegetation environments repeated within each of the three fault compartments of the lake margin and distal alluvial fan. The fault-compartmentalized landscape model is currently supported only by sediment thickness and facies changes across synsedimentary faults, but it provides predictions for spatial variation in the cover abundance of trees, freshwater reservoirs and associated distributions of resources and hazards associated with stone artifact use and discard that can be tested if sample sizes of key paleoenvironmental indicators are increased. © 2011 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.landsc
Keywords: Hominin land use; Landscape paleoanthropology; Olduvai Gorge

Landslide reliability analysis based on transfer coefficient method: A case study from Three Gorges Reservoir - Bi, Renneng; Ehret, Dominik; Xiang, Wei; Schleier, Markus; Jiang, Jiwei; Rohn, Joachim (Journal of Earth Science, 2012)
Keywords: Landslide stability reliability; Monte Carlo method; Three Gorges Reservoir; Transfer coefficient method; Water level fluctuation

Landslides at the Qingjiang River in the downstream area of the Shui Bu Ya dam site, China - Rohn, Joachim; et al. (Journal of China University of Geosciences, 2006)
UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.profes_3.landsl

Landslide susceptibility analysis based on ArcGIS and Artificial Neural Network for a large catchment in Three Gorges region, China - Bi, Renneng; Schleier, Markus; Ehret, Dominik; Xiang, Wei; Rohn, Joachim (Environmental Earth Sciences, 2014)
Keywords: ArcGIS; Artificial Neural Network; Landslide causative factors; Landslide susceptibility; Three Gorges Reservoir

Large-scale geothermal collector systems for 5th generation district heating and cooling networks - Zeh, Robin; Ohlsen, Björn; Philipp, David; Bertermann, David; Kotz, Tim; Jocić, Nikola; Stockinger, Volker (Sustainability, 2021)
Low temperature district heating and cooling networks (5GDHC) in combination with very shallow geothermal energy potentials enable the complete renewable heating and cooling supply of settlements up to entire city districts. With the help of 5GDHC, heating and cooling can be distributed at a low temperature level with almost no distribution losses and made useable to consumers via decentralized heat pumps (HP). Numerous renewable heat sources, from wastewater heat exchangers and low-temperature industrial waste heat to borehole heat exchangers and large-scale geothermal collector systems (LSC), can be used for these networks. The use of large-scale geothermal collector systems also offers the opportunity to shift heating and cooling loads seasonally, contributing to flexibility in the heating network. In addition, the soil can be cooled below freezing point due to the strong regeneration caused by the solar irradiation. Multilayer geothermal collector systems can be used to deliberately generate excessive cooling of individual areas in order to provide cooling energy for residential buildings, office complexes or industrial applications. Planning these systems requires expertise and understanding regarding the interaction of these technologies in the overall system. This paper provides a summary of experience in planning 5GDHC with large-scale geothermal collector systems as well as other renewable heat sources.
CRIS-Team Scopus Importer:2021-06-25
Keywords: 5GDHC; Large-scale geothermal collector; Very shallow geothermal potential; VSGP

Large scale lateral spreading and related mass movements in the Northern Calcareous Alps - Rohn, Joachim; et al. (Bulletin of Engineering Geology and the Environment, 2004)
Lateral spreading is an important geotechnical phenomenon in the Hallstatt zones of the Northern Calcareous Alps where rigid limestones overlie marls and salt clays. Following the last glaciation, mass movements have developed with a general spreading of limestone blocks resulting in a complicated "jigsaw puzzle" of rock. Two typical examples from Mt. Sandling and Mt. Raschberg in the Northern Calcareous Alps of Austria are discussed. © Springer-Verlag 2004.
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.profes_3.larges
Keywords: Calcareous alps; Hallstatt zones; Lateral spreading; Mt. Raschberg; Mt. Sandling; Undrained loading

Large scale mass movements triggered by the Kashmir earthquake 2005, Pakistan - Basharat, Muhammad; Baig, Mirza Shahid; Khan, Muhammad Rustam; Schleier, Markus; Rohn, Joachim (Journal of Mountain Science, 2014)
Keywords: Coseismic mass movements kHimalayas kMuzaffarabad Fault kGeological and tectonic factors kEarthquake kRock fall

Large-scale porphyry-type mineralization in the Central Asian metallogenic domain: A review - Gao, Jun; Klemd, Reiner; Zhu, Mingtian; Wang, Xin-Shui; Li, Jilei; Wan, Bo; Xiao, Wenjiao; Zeng, Qingdong; Shen, Ping; Sun, Jinggui; Qin, Kezhang; Campos, Eduardo (Journal of Asian Earth Sciences, 2017)
A series of porphyry-type Cu-(Mo)-(Au) deposits including some giant world-class deposits such as Kounrad, Aktogai, Kal’makyr, Oyu Tolgoi and Chalukou occur in the Central Asian metallogenic domain (CAMD). The outline of the CAMD almost overlaps with that of the Central Asian orogenic belt (CAOB), which is located between the East Europe, Siberia, Tarim and North China cratons. The CAMD comprises sparsely exposed tectonic slices of Precambrian high-grade metamorphic basement rocks that are sandwiched between Phanerozoic accretionary complexes and arc rocks. According to geological, metallogenic, geochronological and tectonic setting characteristics, the CAMD comprises three metallogenic provinces: (1) the Kazakhstan Cu-Au-Mo, (2) the Mongolia Cu-Au and (3) the Northeast China Mo-Cu metallogenic provinces. Early Paleozoic (∼490 to 440 Ma) and Late Paleozoic (∼330 to 295 Ma) large scale porphyry-type mineralization in the Kazakhstan metallogenic province is intimately associated with the evolution of the Central Tianshan–Yili–Northern Tianshan–Kokchetav–Chingiz Paleozoic arc system which was terminated by the late Permian closure of the western segment of the Paleo-Asian Ocean. In contrast, the ∼370 Ma and ∼240 Ma porphyry-type mineralization of the Mongolia metallogenic province is related to the Tuva–Mongolia arc collage system that was formed during the evolution of the Paleo-Asian Ocean in the Paleozoic and the Mongol–Okhotsk Ocean in the early Mesozoic. Furthermore, the Northeast China metallogenic province was affected by three distinct geodynamic processes that were associated with the Paleo-Asian, Mongol–Okhotsk and Paleo-Pacific Oceans during the Paleozoic (>250 Ma), the early Mesozoic (>200 Ma) and the late Mesozoic (200–90 Ma), respectively. Except for the Early Paleozoic Cu mineralization at Duobaoshan (∼480 Ma) and Bainaimiao (440 Ma), the porphyry-type mineralization of this metallogenic province is predominantly characterized by widespread Mesozoic Mo mineralization. In general, porphyry-type deposits of the CAMD have geological, structural, metallogenic, alteration and fluid characteristics, which are consistent either with those related to the oceanic subductional arc settings of the Circum-Pacific metallogenic domain or with those of the continental collisional environment in the Tethyan metallogenic domain. The involvement of highly oxidized intermediate to felsic magmas is fundamental for the formation of porphyry deposits. Even though the prevalent MASH and slab melting models can be employed to interpret the genesis of some porphyry Cu deposits in the CAMD, a here newly suggested model, which is based on ‘pre-enriched mafic lower crust and the subduction of a relictic mid-oceanic ridge’, is thought to explain the large scale copper mineralization in the Balkhash–West Junggar metallogenic belt of the Kazakhstan metallogenic province. Nevertheless, most of the porphyritic suites associated with the Mo deposits in the Northeast China metallogenic province have relatively depleted mantle-like neodymium and hafnium isotopic compositions, suggesting that the ore-forming granitic magma may have predominantly been derived from juvenile lower crust. Upwelling of asthenosphere may have triggered the melting of the lower crust during post-collisional extension subsequent to the closure of the Paleo-Asian Ocean in the Triassic, the subduction of the Paleo-Pacific ocean in the Jurassic and the thinning of the lithosphere caused by rollback of the Paleo-Pacific plate in the Cretaceous. Ancient crustal components were only locally found to have been involved in the magma source of several medium-large Mo deposits.
Keywords: Porphyry-type deposits; Porphyry-type mineralization; Central Asian metallogenic domain; Central Asian Orogenic Belt

Laser Ablation ICP-MS - Klemd, Reiner; Brätz, Helene (Process Mineralogy – JKMRC Monograph Series in Mining and Mineral Processing: No. 6, 2017)

Last Glacial deep water corals from the Red Sea - Taviani, Marco; López Correa, Matthias; Zibrowius, Helmut; Montagna, Paolo; McCulloch, Malcolm; Ligi, Marco (Bulletin of Marine Science, 2007)
The present Red Sea deep-sea benthos appears impoverished with respect to the adjacent Indian mother-ocean as a result of severe filters, represented by an extremely shallow sill, high salinity, and high temperature. Today, the Red Sea basin hosts a still poorly known deep-water coral fauna of Indian Ocean affinity. During the Pleistocene, conditions were at times suitable as proven by the findings of last glacial corals (Javania insignis Duncan, 1876, and Trochocyathus virgatus sensu Marenzeller, 1907 (not Alcock, 1902), and, possibly, Guynia annulata Duncan, 1872) from seamounts in the north-central part of the basin. A subfossil J. insignis from the Coral Sea peak has been U-series-dated at 26,590 ± 120 yrs. This represents the first documentation regarding the presence of deep-water corals in the Red Sea during the late Pleistocene and predates the postulated basin-wide extinction of normal marine biota that took place at the Last Glacial Maximum. © 2007 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LP.lastgl

Late Carboniferous high-pressure metamorphism of the Kassan Metamorphic Complex (Kyrgyz Tianshan) and assembly of the SW Central Asian Orogenic Belt - Mühlberg, Moritz; Hegner, E.; Klemd, Reiner; Pfänder, J. A.; Kaliwoda, Melanie; Biske, Y. S. (Lithos, 2016)
High-pressure (HP) metamorphism of the Kassan Metamorphic Complex (KMC) in the western Kyrgyz Tianshan has been related to either late Ordovician or late Carboniferous-Permian subduction processes. We report Sm-Nd ages for retrogressed eclogite samples and 40Ar/39Ar cooling ages for enclosing garnet-muscovite samples from the KMC as new age constraints on HP metamorphism and rock exhumation. These data will be used for an upgraded paleogeographic model for late Paleozoic crustal consolidation in the southwestern Central Asian Orogenic Belt. The retrogressed eclogite samples have transitional alkaline to tholeiitic affinity and trace-elementpatterns consistent with protoliths derived from garnet-bearing mantle sources at rifting plate margins. Geothermobarometric data for a retrogressed eclogite sample indicate peak-metamorphic conditions of 540 ± 30 °C at 1.6 ± 0.1 GPa. Samples from different lithotectonic units of the KMC provide coherent Sm-Nd garnet-whole rock ages of 317 ± 4 Ma and 316 ± 3 Ma (2σ). The prograde major-element zoning in the mm-sized garnets in combination with the moderate peak-metamorphic temperature, support our interpretation of the Sm-Nd garnet ages as unambiguous evidence for late Carboniferous HP metamorphism. The Sm-Nd garnet growth ages overlap within-error with the 40Ar/39Ar mica cooling ages of 314 ± 2 Ma and 313 ± 2 Ma (2σ) indicating rapid uplift of the subduction complex after peak metamorphism. The ca. 317-313 Ma HP-exhumation event of the KMC is contemporaneous with those of the Atbashi and Akeyazi (ca. 500 km east in NW China) HP complexes and implies similar collision histories at the South Tianshan Suture to the east and west of the Talas-Fergana Fault (TFF). The exhumation of the KMC and Atbashi HP complexes overlaps with the initiation of the TFF (Rolland et al., 2013) suggesting incipient separation of the Chatkal and Atbashi complexes during rock exhumation and early plate collision.<br
Keywords: Tianshan; eclogite; Sm-Nd garnet ages; 40Ar/39Ar mica ages; Talas-Fergana Fault; Central Asian Orogenic Belt

Late Carboniferous hydrocarbon-seep carbonates from the glaciomarine Dwyka Group, southern Namibia. - Himmler, Tobias; Freiwald, André; Stollhofen, Harald; Peckmann, Jörn (Palaeogeography, Palaeoclimatology, Palaeoecology, 2008)
Limestone deposits with columnar to lenticular geometry (max. 3.2 m in height and 1.5 m in diameter) occur within the uppermost part of the Ganigobis Shale Member, a marine mudstone unit capping the second deglaciation sequence of the glaciomarine Dwyka Group in southern Namibia. The limestones mainly consist of four authigenic carbonate phases (microspar, banded/botryoidal cement, yellow calcite, spheroidal calcite). Extremely negative δ13C values (as low as - 51‰ VPDB) indicate a hydrocarbon-derived origin of the carbonates with biogenic methane being the most likely carbon source. The limestones contain a low-diversity but high-abundance faunal assemblage of tubular fossils. These fossils closely resemble the tubes of modern and fossil seep-dwelling vestimentiferan tube worms in terms of size, shape, arrangement, and taphonomical patterns. © 2007 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LG.lateca
Keywords: Hydrocarbon seeps; Karoo; Methane; Pennsylvanian; Vestimentiferans

Late Carboniferous to Late Permian carbon isotope stratigraphy: A new record from post-Variscan carbonates from the Southern Alps (Austria and Italy) - Buggisch, Werner; Krainer, Karl; Schaffhauser, Maria; Joachimski, Michael; Korte, Christoph; Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 2015)
An integrated study of the litho-, bio-, and isotope stratigraphy of carbonates in the Southern Alps was undertaken in order to better constrain δ13C variations during the Late Carboniferous to Late Permian. The presented high resolution isotope curves are based on 1299 δ13Ccarb and 396 δ13Corg analyses. The carbon isotope record of diagenetically unaltered samples from the Carnic Alps (Austria) and Karavanke Mountains (Slovenia) shows generally high δ13C values, but Late Carboniferous and Early Permian successions are affected by a diagenetic alteration as consequence of glacio-eustatic sea level changes. Negative δ13C excursions are related to low-stand deposits and caused by diagenetic processes during subaerial exposure. The comparison with δ13C records from other parts of the world demonstrate that δ13C values are high in most unaltered samples, an overall negative trend during the Permian, as recently published, is not obvious and negative excursions related to changes in the carbon isotope composition of the global oceanic carbon pool cannot be confirmed, except for the Permian-Triassic boundary interval.
Keywords: Carbon isotopes; Carboniferous; Diagenesis; Permian

Late cretaceous magmatism in the Northern Lhasa subterrane, central Tibet: geodynamic implications - Sun, Miao; Chen, Wei; Klemd, Reiner; Tang, Ju-Xing; Ma, Xu-Dong; Liu, Qing-Ping (International Geology Review, 2022)
Compositional changes of successively emplaced magmatites can be used to infer changes in their petrogenetic evolution and geodynamic setting. The central-northern Lhasa terrane hosts extensive Late Cretaceous magmatism, however, the mechanism that triggered the magmatism and its relationship to the directly preceding Late Cretaceous tectonic transition in the central Tibetan Plateau is still unresolved. Therefore, we conducted a detailed petrological, geochronological, geochemical, and isotopic study on recently identified Late Cretaceous doleritic and granodioritic rocks in the Xiongmei area, northern Lhasa subterrane. The potassic (K2O/Na2O ratios >1) dolerites (ca. 80 Ma) display a post-collisional basaltic shoshonitic signature with uniform moderately enriched whole-rock Sr-Nd and zircon-Hf isotopic compositions ((Sr-87/Sr-86)(t) = 0.7070 to 0.7095, whole-rock epsilon(Nd)(t) = - 2.4 to - 1.3, and zircon epsilon(Hf)(t) = - 5.9 to +1.9), suggesting that they evolved from a similar parental magma and were likely derived by partial melting of an enriched lithospheric mantle metasomatized by hydrous fluids. The granodiorites are geochemically divided into medium-K and high-K calc-alkaline rocks. The medium-K samples (ca. 80 Ma) are generally characterized by low K2O/Na2O ratios <1, whereas the high-K samples (78-76 Ma) display high K2O/Na2O ratios >1. The medium-K samples have positive zircon epsilon(Hf)(t) values from +4.8 to +6.5 and uniform whole-rock e(Nd)(t) values from - 2.4 to - 1.3, which significantly differ from those of the high-K samples that have negative to positive zircon epsilon(Hf)(t) values from - 1.9 to +2.8 and negative whole-rock e(Nd)(t) values from - 8.4 to - 5.1. The medium-K samples are characterized by high Sr contents and Sr/Y ratios, coupled with low Y and HREE contents, similar to adakitic compositions, and were interpreted to have been derived from deep partial melting of the foundering juvenile garnet-bearing mafic lower crust at relatively low temperatures. Compared to the medium-K samples, the high-K samples have lower Sr/Y and (La/Yb)(N) ratios, coupled with flat HREE patterns and distinct negative Eu, Sr and Ti anomalies and are most likely derived from shallower partial melting of the K-rich juvenile lower crust at relatively high temperatures. Considering the occurrence of variable magmatism in the central-northern Lhasa subterrane during the Late Cretaceous, the change in magma composition and lower crustal melting conditions (cold-deep vs. hot-shallow) suggest that the lithospheric mantle keel was partially detached by small-scale mantle convection in response to the low-angle Neo-Tethys-associated subduction between 85 and 70 Ma.
CRIS-Team WoS Importer:2022-07-29

Late Cretaceous tectonothermal evolution of the southern Lhasa terrane, South Tibet: Consequence of a Mesozoic Andean-type orogeny - Dong, Xin; Zhang, Zeming; Klemd, Reiner; He, Zhenyu; Tian, Zuolin (Tectonophysics, 2018)
The Lhasa terrane of the southern Tibetan Plateau participated in a MesozoicAndean-type orogeny caused by the northward subduction of the Neo-Tethyan oceanic lithosphere. However, metamorphic rocks, which can unravel details of the geodynamic evolution, are rare and only exposed in the south-eastern part of the Lhasa terrane. Therefore, we conducted a detailed petrological, geochemical and U–Pb zircon geochronological study of the late Cretaceousmetamorphic rocks and associated gabbros from the Nyemo inlier of the southern Lhasa terrane. The Nyemo metamorphic rocks including gneisses, schists, marbles and calc-silicate rocks, experienced peak amphibolite-faciescontact metamorphism under P–T conditions of 3.5–4.0 kbar and 642–657 °C with a very high geothermal gradient of 45–50 °C/km, revealing a distinct deflection from the steady-state geotherm during low-pressure metamorphism. Inherited magmatic zircon cores from the metamorphic rocks yielded protolithages of 197–194 Ma, while overgrowth zircon rims yielded metamorphic ages of ca. 86 Ma. Whole-rock chemistry and zircon Hf isotopes suggest that the protoliths of the gneisses and schists are andesites and tuffs of the early JurassicSangri Group, which were derived from a depleted mantle source of a continental arc affinity. The coeval intimately-associated gabbro (ca. 86 Ma) crystallized under P–T conditions of 3.5–5.3 kbar and 914–970 °C, supplying the heat flux high enough to cause the contact metamorphism of the Sangri Group rock types. We propose that the intrusion of the gabbro and a simultaneous pressure increase of up to 4.0 kbar, which is related to crustal thickening due to crustal overthrusting and the intrusion of mafic material, resulted in the late Cretaceous metamorphism of the early Jurassic Sangri Group during an Andean-type orogeny. Furthermore the Nyemo metamorphic rocks, which have previously been considered to represent slivers of the Precambrianmetamorphic basement of the Lhasa terrane, are late Cretaceous metamorphic supracrustal rocks.
Keywords: Late Cretaceous contact metamorphism; Gabbroic intrusion; Intrusion-related perturbed geothermal gradient; Andean-type orogeny; Southern Lhasa terrane

Late Devonian carbon isotope chemostratigraphy: A new record from the offshore facies of South China - Zhang, Xinsong; Joachimski, Michael; Over, D. Jeffrey; Ma, Kunyuan; Huang, Cheng; Gong, Yiming (Global and Planetary Change, 2019)
Keywords: Bio-events; Plants; Stable carbon isotopes; Famennian; Frasnian; Tectonics

Late Devonian greenhouse-icehouse climate transition: New evidence from conodont δ18O thermometry in the eastern Palaeotethys (Lali section, South China) - Zhang, Xinsong; Joachimski, Michael; Gong, Yiming (Chemical Geology, 2021)
The Late Devonian is considered as a crucial climatic transition from the Devonian greenhouse to Carboniferous icehouse. Published Late Devonian marine palaeotemperature records are mainly based on conodont δ18Oapatite data from the Rheic Ocean. In order to reconstruct palaeotemperature variations in the eastern Palaeotethys, oxygen isotopes were measured on the latest Givetian to latest Famennian conodonts from the Lali section (South China). Assuming constant seawater δ18O, the early to middle Frasnian is marked by a warming trend (−1.5‰ shift in δ18Oapatite), with warmest temperatures reconstructed in FZ 11 (FZ = Frasnian Zonation). Late Devonian cooling during the middle to late Famennian (velifer to ultimus Zone) is documented by a long-term positive δ18Oapatite shift of +2‰. This increase corresponds to a similar δ18Oapatite increase in the Rheic Ocean and can be explained by cooling as well as the formation of ice masses as evidenced by the occurrence of glacial sediments in Gondwana and Euramerica during the late Famennian. The Late Devonian δ18Oapatite record largely matches 2nd-order T-R cycles. The δ18Oapatite record from the Lali section shows several short-term positive excursions coinciding with Late Devonian bio-events as the Middlesex (+0.5‰ δ18Oapatite), Lower Kellwasser (+1‰ δ18Oapatite) and Upper annulata (+0.8‰ δ18Oapatite) events. However, due to the lower sampling resolution of the F-F (Frasnian-Famennian) boundary interval, we did not recognize a positive shift in δ18Oapatite for the Upper Kellwasser event as reported from other sections.<br
Keywords: Late Devonian; Conodont oxygen isotope; Palaeotemperatures; Climate change; Bio-events; South China

Lateglacial and Holocene environmental changes in Ganga plain, Northern India - Joachimski, Michael; et al. (Quaternary Science Reviews, 2004)
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.LAG.lategl

Late Jurassic fishes from Longing Gap, Antarctic Peninsula - Arratia, Gloria; Scasso, R. A.; Kießling, Wolfgang (Journal of Vertebrate Paleontology, 2004)
Few records of Late Jurassic fishes have been reported previously from Antarctica. They include an indeterminate teleost from the Ameghino (Nordenskjöld) Formation at Longing Gap and two incomplete aspidorhynchiforms from James Ross Island, all of presumed Late Jurassic age. New fish material recently recovered in the Upper Jurassic of Longing Gap is described. The new material consists of one piece of body squamation, which, based on the structure of the scales, corresponds to a new genus and species (Ameghinichthys antarcticus gen. et sp. nov.) of an indeterminate actinopterygian family; one aspidorhynchiform identified as Vinctifer sp. due to the structure and distribution of the scales; and numerous specimens of a new ichthyodectiform, Antarctithrissops seymouri gen. et sp. nov. This new genus differs from European ichthyodectiforms in the shape of the preopercle, the presence of long sensory preopercular branches almost reaching the posterior margin of the bone, and the uncommon structure of the scales, with a fine layer of bone obscuring the circuli. The presence of Vinctifer in the Antarctic is consistent with its other Gondwanan records. The Ichthyodectiformes, previously known from four European genera, extends the distribution of the group to the southernmost part of the Southern Hemisphere during the Late Jurassic. In contrast to most non-teleostean fishes, the known Late Jurassic teleosts apparently are species endemic to restricted areas in the Southern Hemisphere. © 2004 by the Society of Vertebrate Paleontology.
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.LP.lateju

Late Jurassic (Oxfordian-Kimmeridgian) brachiopods of the El Bayadh Area (Central Saharan Atlas, Algeria): biostratigraphy, stratigraphic revision, Paleobiogeography and paleoecology - Mahboubi, Chikh Younes; Radulovic, Barbara V.; Ouali Mehadji, Abdelkader; Ayoub-Hannaa, Wagih; Munnecke, Axel (Historical Biology, 2021)
The Upper Jurassic rocks of the El Bayadh Area (Central Saharan Atlas, Algeria) are composed of mixed siliciclastic-carbonate rocks, which were roughly assigned to a Kimmeridgian-Hauterivian age in previous studies. Based on our studies, the succession can be subdivided into five new formations; from base to top: the Theniet Et-Temar, Ksel, Laguremi, Boualem, and the Sfissifa formations. Brachiopod faunas have been recorded from two levels. The lower one is located in the Theniet Et-Temar Formation, and the upper one in the Sfissifa Formation. Two brachiopod species Lacunosella (Lacunosella) arolica and Moeschia alata from the first level and Xestosina arguta from the second level have been recorded for the first time not only in Algeria but also in Africa. Based on the new findings, the age of the studied section can be restricted to the middle Oxfordian at the base and to the upper Kimmeridgian at the top. The stratigraphic successions between the two levels (70 m) are nearly barren except for dinosaur footprints, which were tentatively assigned to a Lower Cretaceous age by previous workers. However, this succession can be attributed to an upper Oxfordian-lower Kimmeridgian age now based on its brachiopod faunas.
CRIS-Team WoS Importer:2021-02-05

Late Jurassic radiolarians from the Antarctic Peninsula - Kießling, Wolfgang (Micropaleontology, 1999)
Radiolarian faunas from the type section of the mostly Late Jurassic Ameghino Formation (= Nordenskjold Formation) on the Antarctic Peninsula (Longing Gap, northern Graham Land) are described taxonomically, analyzed stratigraphically and interpreted paleoecologically, based on quantitative observations. Three hundred and fifty-nine species have been discovered in total; some two hundred of them are probably new. Twenty-eight new species and three new subspecies are described. The most abundant and characteristic species are used to present a regional radiolarian stratigraphy. The radiolarian faunas show distinct high-latitude characteristics. They are demarcated by high abundances of Parvicingula s.1. and spongy spumellarians, whereas Tethyan taxa like Mirifusus, Ristola, Tethysetta, Tritrabs, Syringocapsidae, Spongocapsulidae, and Xitidae are absent or very rare. The average diversity is high, but significantly lower than in coeval Tethyan samples. Cluster analysis reveals a major change in faunal composition near the early-late Tithonian boundary. The characteristics of the Antarctic radiolarian faunas allow an Austral Province to be defined extending from circum-Antarctica to northeast Australia. The Austral radiolarian province is similar to the Northern Tethys and Southern Boreal Provinces sensu Pessagno and Blome (1986), but exhibits some differences. The new data allow the biogeographic scheme of Pessagno and Blome (1986) to be revised and permit the introduction of a preliminary global paleobiogeographic map for the Tithonia
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LP.lateju

Late Jurassic temperatures for the southern Tethyan margin based on belemnites δ18O from the Ouarsenis Mountains, northwestern Algeria - Sadji, Radouane; Munnecke, Axel; Benhamou, Miloud; Alberti, Matthias; Belkhedim, Salim; Ramdane, Nabil (Palaeogeography, Palaeoclimatology, Palaeoecology, 2021)
This study presents the first record of stable carbon and oxygen isotopes of well-preserved belemnites and bulk sediment from the Upper Jurassic pelagic carbonates of the Ouarsenis Mountains (northwestern Algeria), which were deposited at the southern margin of the Tethys ocean. Cathodoluminescence and scanning electron microscopy was used to eliminate potentially diagenetically altered specimens (brachiopods, aptychi, and some belemnites). Ultimately, 55 belemnite specimens were used to reconstruct water temperatures for the Middle Oxfordian to the Early Tithonian. Their δ18Ocarb values ranged from −0.35‰ to −3.88‰, suggesting warm and mostly stable temperature conditions during the Late Jurassic. Using a δ18Osea value of 0‰ for the tropical palaeolatitude of 15–20°N, the δ18Ocarb values of the well-preserved belemnite rostra translate into average temperatures of 27.8 °C in the Middle Oxfordian (Gregoryceras transversarium Zone), 27.0 to 27.5 °C in the Late Oxfordian (Epipeltoceras bimmamatum and Idoceras planula zones, respectively), 26.2 °C in the Early Kimmeridgian, and 27.3 °C in the Early Tithonian (Hybonoticeras hybonotum Zone).
CRIS-Team Scopus Importer:2021-01-29
Keywords: Bulk sediment; Palaeoclimate; Pelagic carbonates; Stable isotopes; Tropical palaeolatitude

Late Jurassic (Volgian) radiolarians from Central Spitsbergen - A preliminary study - Nakrem, Hans Arne; Kießling, Wolfgang (Norwegian Journal of Geology, 2012)

Late Neoproterozoic-to-recent long-term t-T-evolution of the Kaoko and Damara belts in NW Namibia - Salomon, Eric; et al. (International Journal of Earth Sciences, 2020)
This research aims to reconstruct the Late Neoproterozoic-to-recent long-term time-temperature-evolution of the NW Namibian Kaoko and Damara belts combining numerical modeling of new thermochronological data with previously published geochronological data, i.e., U-Pb, Sm-Nd, and Rb-Sr analyses, and K/Ar, Ar-40/Ar-39 low-temperature thermochronology. Consequently, we retrieve a coherent long-term time-temperature-evolution of the NW Namibian Neoproterozoic basement rocks including rates of exhumation and subsidence periods over the last 500 Myr. Neoproterozoic basement rocks indicate fast post-Pan African/Brasiliano cooling and exhumation, reheating, or rather subsidence during the development of the Paleozoic-to-Mesozoic SW Gondwana intraplate environment and a significant thermal overprint of the rocks during South Atlantic syn- to post-rift processes, and therefore, resemble the opponent SE Brazilian time-temperature-evolution. We provide an overview of thermochronological data including new apatite and zircon fission-track data derived from Neoproterozoic, Late Paleozoic, and Lower Cretaceous rocks. Apatite fission-track ages range from 390.9 +/- 17.9 Ma to 80.8 +/- 6.0 Ma in the NW Kaoko Belt with youngest ages confined to the coastal area and significant age increase towards the inland. New zircon apatite fission-track data reveal ages between 429.5 +/- 47.8 and 313.9 +/- 53.4 Ma for the rocks of the Kaoko Belt. In the central Damara Belt, new apatite fission-track ages range between 138.5 +/- 25.3 Ma to 63.8 +/- 4.8 Ma. Combined apatite fission-track age distributions from Angola to Namibia and SE Brazil correlate for both sides of the South Atlantic passive continental margin and the reset AFT ages overlap with the lateral Parana-Etendeka dike swarm distribution.
Keywords: Long-term t-T-evolution; Thermochronology; Numerical modeling; South Atlantic passive continental margin of NW Namibia

Late Ordovician microbial reefs in the Lianglitag Formation (Bachu, Tarim, NW China) - Zhang, Yuanyuan; Li, Yue; Munnecke, Axel (Facies, 2014)
Reefs in the Late Ordovician are usually built up by metazoans, whereas in the Early and Middle Ordovician microbial reefs are dominating. In the Late Ordovician (Katian) Lianglitag Formation, at Bachu, Tarim, NW China, however, three distinct stages of thrombolithic microbial reefs are exposed. The lower and upper reef intervals are characterized by widespread microbial carbonates with almost constant thicknesses (biostromes). The middle reef interval exposes dome-like mounds, and shows a higher diversity of reef-building and reef-dwelling organisms. Calcareous algae such as Vermiporella are abundant, but also other components such as fragments of Halysis, brachiopods, molluscs, echinoderms, bryozoans, and trilobites have been found in the microbial reef units. The purpose of this study is to describe for the first time the composition and microfacies of the reefs in this remote area. Especially the question of whether or not these Late Ordovician reefs represent remnants of the Early/Middle Ordovician microbial-dominated reef type just lacking Calathium and lithistid sponge is addressed. The results indicate that the local conditions on the leeward side of the carbonate platform, where waters are less well agitated and thus less well oxygenated, and probably also characterized by temporarily elevated water temperatures hampering the growth of metazoan reefs, were responsible for the proliferation of the Late Ordovician microbial reefs in the Bachu area. © 2014 Springer-Verlag Berlin Heidelber
Keywords: Biotic structures; Katian; Late Ordovician; Microbial reefs; NW China; Tarim

Late orogenic faulting and associated vein mineralisation in Saxothuringian metasediments - implications for crustal strength estimates - Dietl, Carl; Donhauser, Ines; Bestmann, Michel; Scharfenberg, Lars; de Wall, Helga (Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 2022)
Palaeozoic metasediments, recovered from a well bore at the E' margin of the Franconian Basin in NE Bavaria, give insight into the Variscan basement west of the Bohemian Massif. Quartz veins are abundant in the folded and cleaved pelitic to psammitic sequence. They are mainly restricted to coarse-grained massive metasandstone. The structural inventory of the quartz veins and cross-cutting relationships between them indicates their formation during three brittle deformation phases and corresponding fluid pulses at a depth of ca. 7 km. The metasandstone has a low porosity (1.1 to 1.5 vol-%) and is almost impermeable (permeability = 1.70e-17). Triaxial tests characterise the metasandstone as strong and very cohesive lithology (C0: 185.52 MPa, S0: 52.11 MPa) that can sustain high compressive stresses. Faulting and vein formation seem to be triggered by high fluid pressure which might have built up in the low permeable metasandstone. The most probable timing for fracturing and vein formation is shortly after the transition from compression to extension tectonics late in the orogenic history of the Variscides during orogenic collapse. At this changeover point effective stresses are decreasing, because fluid pressure becomes more effective as driving force for (hydraulic) fracturing. The generated fracture structures (from vein to fault scale) are preferably orientated in N-S and NW-SE directions. Both orientations represent prominent and persistent regional fault trends in the area not only for Variscan structures but also for younger Permo-Mesozoic to Cenozoic strata of the Franconian Basin.
CRIS-Team WoS Importer:2022-12-02

Late Paleozoic and Late Triassic limestones from North Palawan Block (Philippines): Microfacies and paleogeographical implications - Kießling, Wolfgang; et al. (Facies, 2000)
Selected Late Paleozoic and Triassic limestone exposures were studied on northern Palawan Island, Philippines, with regard to microfacies, stratigraphy and facies interpretation. Although some of the outcrops were already reported in literature, we present the first detailed microfacies study. Late Paleozoic carbonates in the El Nido area are represented by widley distributed Permian and locally very restricted Carboniferous limestones. Of particular interest is the first report of Carboniferous limestones in the Philippines dated by fossils. Fusulinids indicate a 'Middle' Carboniferous (Moscovian-Kasimovian) age of the Paglugaban Formation only known from Paglugaban Island. The Permian Minilog Formation consists mostly of fusulinid wackestones and dasycladacean wacke-/packstones. Fusulinid datings (neoschwagerinids and verbeekinids) provide a Guadalupian (Wordian-Capitanian) age. The depositional setting of the Middle Permian carbonates corresponds to a distally steepened ramp with biostromes built by alatoconchid bivalves locally associated with richthofeniid brachiopods. Late Triassic limestones occur in isolated exposures on and around Busuanga Island (Calamian Islands). The age of the investigated carbonates is Rhaetian based on the occurrence of Triasina hantkeni Majzon. Microfacies data indicate the existence of reefs (Malajon Island) and carbonate platforms (Kalampisanan Islands, Busuanga Island, Coron Island). Reef boundstones are characterized by abundant solenoporacean red algae, coralline sponges and corals. Platform carbonates yield a broad spectrum of microfacies types, predominantly wacke- and packstones with abundant involutinid foraminifera and some calcareous algae. These facies types correspond to platform carbonates known from other parts of Southeast Asia (Eastern Sulawesi and Banda Basin; Malay Peninsula and Malay Basin). The Philippine platform carbonates were deposited on and around seamounts surrounded by deeper water radiolarian cherts. The new data on facies and age of the Philippine Permian and Triassic carbonates contradict a close paleogeographical connection between the North Palawan Block and South China and arise problems for the currently proposed origin of the North Palawan Block at the paleomargin of South China. We hypothesize that North Palawan was part of the Indochina Block during the Carboniferous and Permian, separated from the Indochina Block during the Middle Permian and collided with the South China Block in the Late Cretaceous.
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LP.latepa
Keywords: Carbonate ramps and platforms; Carboniferous; Late Triassic; Microfacies analysis; Middle Permian; Paleogeography; Philippines (Palawan); Reefs

Late Pan-African granite emplacement during regional deformation, evidence from magnetic fabric and structural studies in the Hammamat-Atalla area, Central Eastern desert of Egypt - Greiling, R. O.; de Wall, Helga; Sadek, M. F.; Dietl, C. (Journal of African Earth Sciences, 2014)
Keywords: Ediacaran; Egypt; Escape tectonics; Late orogenic granite; Magnetic fabric (AMS); Pan-African orogeny

Late Pennsylvanian fishes from the Finis Shale of North-Central Texas - Ivanov, Alexander; Seuß, Barbara (54th Annual Meeting, South-Central Section of the GSA, 2020)
The fossil-rich deposits from the Finis Shale (Graham Formation) at the "spillway section" near Jacksboro (North-Central Texas) are dated as early Virgilian (early Gzhelian; Late Pennsylvanian) in age. The Finis Shale is part of a cyclothem and represents the shallowing upwards sequence at this outcrop. The shale deposits are capped by phylloid algae and fusulinid carbonates of the Jacksboro Limestone. Various chondrichthyan macroremains such as Glikmanius, Orodus, Campyloprion, or Petalodus are known from these deposits. A diverse assemblage of fish microremains is now discovered in and described from the Finis Shale deposits. The micro-fossil assemblage includes numerous chondrichthyan teeth and scales, while acanthodian scales and actinopterygian teeth and scales are rare. The chondrichthyan microremains are taxonomically more diverse and represented by teeth of the bransonelliform Bransonella nebraskensis Johnson, by the symmoriiform Denaea cf. williamsi Ginter et Hansen, and yet undetermined stethacanthids. The ctenacanthiforms Heslerodus divergens (Trautschold) and Glikmanius sp., sphenacanthid euselachians, the neoselachian Cooleyella amazonensis Duffin, Richter et Neis, the petalodontids Euglossodus sp. and cf. Tanaodus sp., and eugeneodontid remains are also preserved. Symmoriiform denticles and chondrichthyan scales of various types are also found. The new occurrence of fishes demonstrates the presence of chondrichthyan taxa with different food specialization in the early Virgilian faunal communit

LATE PERMIAN PLUME AND NEOPROTEROZOIC SUBDUCTION-MODIFIED MANTLE INTERACTION: INSIGHTS FROM GEOCHRONOLOGY AND Sr-Nd-O ISOTOPES OF MAFIC DIKES OF THE WESTERN EMEISHAN LARGE IGNEOUS PROVINCE br - Wang, Yanning; Xue, Shengchao; Klemd, Reiner; Yang, Lin; Zhao, Feng; Wang, Qingfei (American Journal of Science, 2022)
Geochronological investigations of mafic dikes along the southwest-ern margin of the Emeishan large igneous province (ELIP) in the South China block display a restricted range of U-Pb zircon, baddeleyite, and apatite isotopic ages rang -ing from 263 to 257 Ma, which overlaps with that of previously studied ELIP basalts and mafic intrusions. The dikes are divided into high-Ti and low-Ti groups, whereby the latter is further divided into two subgroups (low-Ti group-1 and-2). The high-Ti group rocks (Ti/Y > 500) are characterized by ocean island basalt-like trace element patterns with mantle-like zircon 4318O of 5.0 +/- 0.10 parts per thousand and slightly enriched sNd(t) val-ues of -1.0 to +1.0. The low-Ti group-1 rocks (Ti/Y < 500) have trace element pat-terns similar to those of the high-Ti group, yet generally with weak negative Nb-Ta anomalies, lower (Sm/Yb)N ratios, elevated zircon 4318O (6.6 +/- 0.33 parts per thousand), and highly variable sNd(t) values (-3.9 to +3.2). The low-Ti group-2 rocks (Ti/Y < 500) are characterized by pronounced negative Nb-Ta anomalies, more negative sNd(t) (-8.4 to -6.6) values, and higher initial 87Sr/86Sr ratios than those of the other two groups. The compositional variations of the high-Ti group and the low-Ti group-1 rocks, in conjunction with the negative correlation between the sNd(t) values and the (Th/ Nb)N ratios, suggest that the two groups were generated from an isotopically hetero-geneous mantle plume at different depths, and experienced varying degrees of crustal contamination (but < 20 wt.%). The high-Ti group rocks are considered to have originated from a deeper garnet-stable source, and the low-Ti group-1 rocks from a shallower source. Mixing calculations indicate that the highly enriched Sr-Nd isotopes of the low-Ti group-2 rocks cannot be explained by crustal contamination. A subduction-modified mantle source is required to account for the arc-like geochemi-cal characteristics of this group. This is consistent with the spatial overlap of the low-Ti group-2 rocks and previously studied geochemically similar samples with rocks from the Neoproterozoic subduction zone along the western margin of the South China block. Furthermore, a fertilized mantle is also consistent with the variable 4318O values of various mafic-ultramafic rocks of the western and central ELIP due to the involvement of recycled oceanic crustal materials. Our results are in accordance with the model that the western ELIP late Permian magmatism was generated by the interaction of two distinct sources, that is, an isotopically heterogenous mantle plume and a Neoproterozoic subduction-modified, Nd isotope-enriched litho-spheric mantle with distinct heterogenous oxygen isotope characteristics.
CRIS-Team WoS Importer:2022-11-18

Late Permian to Late Triassic Large Igneous Provinces: Timing, Eruptive Style and Paleoenvironmental Perturbations - Boscaini, Andrea; Callegaro, Sara; Sun, Yadong; Marzoli, Andrea (Frontiers in Earth Science, 2022)
The emplacement of the Siberian Traps, the Central Atlantic Magmatic Province (CAMP) and the Wrangellia have been linked to the end-Permian, the end-Triassic mass extinctions, and to the Carnian Pluvial Episode (CPE), respectively. Exploring the timing, eruptive styles, and volatile degassing of these Large Igneous Provinces (LIPs) is crucial to understand their causal link to the catastrophic environmental crises that punctuated the Triassic. In this study we review the main characteristics of these LIPs, emphasizing common features and differences, and discussing aspects that are still in debate. Estimates of CO2 budgets and emissions from the three LIPs are based on the Nb content of little evolved basalts and highlight that early Siberian Traps and CAMP and high-Ti Wrangellia volcanics were quite CO2-rich. On the contrary, other volcanics from the three LIPs probably emitted relatively low amounts of CO2, which reinforces the possibility that thermogenic reactions between sills and sediments were additional fundamental suppliers of climate-modifying gases.
CRIS-Team Scopus Importer:2022-05-06
Keywords: carnian crisis; central atlantic magmatic province (CAMP); large igneous province; mass extinction; siberian traps; triassic; wrangellia LIP

Late Pliocene grassland from Olduvai Gorge, Tanzania. - Bamford, Manon K.; Stanistreet, Ian G.; Stollhofen, Harald; Albert, Rosa M. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2008)
The Olduvai fossil plants documented by us in this paper are the first direct evidence for open grassland in the late Neogene of Africa based on macroplant remains. Silicified remains of herbaceous ground cover are exceptionally well preserved in situ within Late Pliocene sediments below the initial pyroclastic ash surge unit of Tuff IF in the uppermost part of Bed I, Olduvai Gorge, northern Tanzania. Published radiometric and palaeomagnetic dates place this grass layer between 1.839 + 0.005 Ma and 1.785 + 0.01 Ma. Exposed at localities on the south side of the Gorge this herbaceous ground cover grew on a floodplain developed on a dried out lake bed, following pronounced lake retreat of saline-alkaline palaeo-Lake Olduvai during a developing dry climatic phase. Sheathed basal culms, rhizomes and roots are interpreted as those of one or more small mat-forming grasses or less likely, sedges. Small dicotyledonous herbs were probably also present. The proximity of adjacent plants indicates a relatively dense ground cover. Roots extended at least 8 cm below the ground surface. Aerial parts of the plants were absent or were not preserved when the weathered basal culms were covered by a thin layer of brown waxy clay, followed by fallout of pyroclastic ash. Both units were mostly eroded away prior to emplacement of a wet, cool pyroclastic surge which then buried and preserved in situ remnants of the herbaceous ground cover. Preservation of the semi-woody rhizomes implies well-drained soils, otherwise the plant material would have quickly rotted. Collections from discontinuous exposures indicate the grassland covered an area of at least a few hectares. This open grassland would have provided grazing for the Late Pliocene fauna. © 2007 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LG.latepl
Keywords: Grassland; Macrofossils; Olduvai Gorge; Serengeti ecosystem; Terminal Neogene

Late quaternary climate change shapes island biodiversity - Weigelt, Patrick; Steinbauer, Manuel; Cabral, Juliano; Kreft, Holger (Nature, 2016)
Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration–extinction dynamics1, or as geologically dynamic with biodiversity resulting from immigration–speciation–extinction dynamics influenced by changes in island characteristics over millions of years2. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels3,4 and caused massive changes in island area, isolation and connectivity5, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory2,6. Consequences of these oscillations for present biodiversity remain unassessed5,7. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics.

Late to post-Variscan basement segmentation and differential exhumation along the SW Bohemian Massif, central Europe - Eberts, Andreas; Fazlikhani, Hamed; Bauer, Wolfgang; Stollhofen, Harald; de Wall, Helga; Gabriel, Gerald (Solid Earth, 2021)
The exposed Variscan basement in central Europe is well-known for its complex structural and lithological architecture resulting from multiple deformation phases. We studied the southwestern margin of the Bohemian Massif, which is characterized by major and long-lived shear zones, such as the Pfahl and Danube shear zones, extending over >ĝ€¯100ĝ€¯km and initiated during Variscan tectonics. We integrated Bouguer gravity anomaly and lidar topographic data analyses and combined our results with available data and observations from low-Temperature thermochronology, metamorphic grades, and the exposed granite inventory to detect patterns of basement block segmentation and differential exhumation. Three NW-SE-striking basement blocks are bordered by the Runding, Pfahl, and Danube shear zones from the northeast to the southwest. Basement block boundaries are indicated by abrupt changes in measured gravity patterns and metamorphic grades. By applying high-pass filters to gravity data in combination with lineament analysis, we identified a new NNW-SSE-striking tectonic structure (Cham Fault), which further segments known basement blocks. Basement blocks that are segmented by the Cham Fault differ in the abundance and spatial distribution of exposed late Variscan granites and are further characterized by variations in apparent thermochronological age data. Based on our observations and analyses, a differential exhumation and tectonic tilt model is proposed to explain the juxtaposition of different crustal levels. Block segmentation along the NW-SE-striking Pfahl and Runding shear zones most likely occurred prior, during, and after late orogenic granite emplacement at ca. 320ĝ€¯±ĝ€¯10ĝ€¯Ma, as some of the granites are cross-cut by the shear zones, while others utilized these structures during magma ascent and emplacement. In contrast, activity and block segmentation along the Cham Fault occurred after granite emplacement as the fault sharply truncates the granite inventory. Our study provides evidence of intense and continuous fault activities during late and post-orogenic times and highlights the importance of tectonic structures in the exhumation and juxtaposition of different crustal levels and the creation of complex lithological patterns in orogenic terrains.
CRIS-Team Scopus Importer:2021-10-29

Late Wenlock carbon isotope excursions and associated conodont fauna in the Podlasie Depression, eastern Poland: a not-so-big crisis? - Jarochowska, Emilia; Munnecke, Axel (Geological Journal, 2016)
The middle Silurian ‘big crisis’ refers to a graptolite extinction event and faunal turnover at the onset of a double-peaked positive carbon isotope excursion. The crisis has been proposed to affect conodonts, giving rise to a sophisticated palaeoecological model of their stepwise extinction, known as the Mulde Event. However, the impact of the event on conodont faunas outside Gotland and the Silurian Baltic Basin remains unknown. Here, it is examined in the Widowo IG-1 core (E Poland). The middle Silurian succession in this core represents foreshoal, shoal, and lagoonal settings on a tropical carbonate ramp on the shelf of the Eastern European Craton. Three positive δC excursions have been identified; the two upper excursions correlate with the Mulde isotope anomaly and with two global eustatic regressions. Conodont species proposed to be affected by the extinction event either were not observed or ranged through the extinction interval. Changes in their frequencies are best explained by the sequence stratigraphic architecture of the late Wenlock strata in the Widowo IG-1 core. The little impact of the ‘big crisis’ may reflect facies homogeneity across the studied interval, supporting the hypothesis that the late Wenlock conodont turnover in epicontinental settings was primarily driven by eustatically controlled facies shifts. Copyright © 2015 John Wiley & Sons, Lt
Keywords: Baltica; extinction; gamma ray stratigraphy; Homerian; lundgreni event; Mulde Event; sequence stratigraphy

Latitudinal trends in Cenozoic reef patterns and their relationship to climate. Carbonate Systems during the Oligocene-Miocene climatic transition - Perrin, Christine; Kießling, Wolfgang (IAS Special Publications, 2010)
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LP.latitu

Lattice preferred orientation of talc and implications for seismic anisotropy in subduction zones - Lee, Jungjin; Jung, Haemyeong; Klemd, Reiner; Tarling, Matthew S.; Konopelko, Dmitry (Earth and Planetary Science Letters, 2020)
Strong seismic anisotropy is generally observed in subduction zones. Lattice preferred orientation (LPO) of olivine and elastically anisotropic hydrous minerals has been considered to be an important factor causing anomalous seismic anisotropy. For the first time, we report on measured LPOs of polycrystalline talc. The study comprises subduction-related ultrahigh-pressure metamorphic schists from the Makbal Complex in Kyrgyzstan-Kazakhstan and amphibolite-facies metasomatic schists from the Valla Field Block in Unst, Scotland. The here studied talc revealed a strong alignment of (001) planes (sub)parallel to the foliation and a girdle distribution of [100] axes and (010) poles (sub)parallel to the foliation. The LPOs of polycrystalline talc produced a significant P-wave anisotropy (AVp = 72%) and a high maximum S-wave anisotropy (max AVs = 24%). The results imply that the LPO of talc influence both the strong trench-parallel azimuthal anisotropy and positive/negative radial anisotropy of P-waves, and the trench-parallel seismic anisotropy of S-waves in subduction zones.
CRIS-Team Scopus Importer:2020-03-10
Keywords: lattice preferred orientation; seismic anisotropy; subduction zone; talc

Lava penetrating water: Submarine lava flows around the coasts of Pico Island, Azores. - Mitchell, Neil C.; Beier, Christoph; Rosin, Paul L.; Quartau, Rui; Tempera, Fernando (Geochemistry Geophysics Geosystems, 2008)
Bathymetry data collected with a multibeam echo sounder around Pico Island, Azores (Portugal), reveal a remarkable series of lava flows on the island's shelf with a variety of pristine structures that suggest how lava behaves on entering water. Many flows are dendritic in plan view, some with channels and tumuli. Dendritic geometries are interpreted to arise from flow fronts repeatedly arrested by enhanced cooling and magma pressure subsequently causing new breakouts. Cascades of elongated flow fingers also occur, with individual fingers of comparable diameters to the largest known megapillows. Some flows have wide transverse clefts, in cases separating flows into segments, which are interpreted as caused by their upper surfaces having solidified, while their still-fluid cores allowed the surfaces to extend. A number of flows moved onto the shelf as large bodies, stopped, and then sourced smaller lobes forming the dendritic patterns. This two-stage evolution and the tumuli (which lie on a low gradient immediately below a steep nearshore gradient) suggest that, after initial emplacement and development of a crust by cooling, some flows pressurized. Once movements ceased and viscous stresses dissipated, magma static pressure developed from the weight of flow interiors passing over cliffs and nearshore gradients. One group of flows traverses the island's submarine slope, so direct supply of lava to the slopes is possible, although volumetrically how important it is to the island's internal composition is difficult to tell from these data. On the basis of observed strong surf erosion of historical flows, these delicate structures probably could not have survived passage through a moving sea level unmodified by erosion so they are unlikely to be pre-Holocene subaerial flows. They are interpreted to have formed in the Holocene from flows penetrating sea level or possibly some from nearshore tube openings or vents. Such flows and abundant clastic deposits are ephemeral features that become remobilized by surf during times of lower sea level. The shelves of active volcanic islands are therefore active geologically and are far from being simple products of erosional truncation as was once envisaged. Copyright 2008 by the American Geophysical Union.
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.legeo.lavape
Keywords: Lava channel; Submarine lava flow; Tumuli; Volcanic landslides; Volcanic ocean island

Lava/sediment interaction in desert settings; are all peperite-like textures the result of magma-water interaction? - Jerram, Dougal A.; Stollhofen, Harald (Journal of Volcanology and Geothermal Research, 2002)
This study reports on lava-sediment interaction in dry depositional settings focusing on the Early Cretaceous volcano-sedimentary sequence in the Huab Basin, NW Namibia, as a detailed example. Here an active aeolian sand sea (erg) system was progressively engulfed by lavas of the Etendeka Flood Basalt Province 133 Ma BP. This volcanic flooding resulted in: (1) the unprecedented preservation of large parts of the active dune system; (2) the development of a variety of sediment interlayers; and (3) a record of excellent examples of the dynamic interaction between lava and aeolian sand. The lava-sediment interaction happens on a variety of scales from simple sediment interbeds within the lavas at a large scale down to complex breccia horizons and bulbous lava-sediment contacts at small scales. 'Peperite' like textures are found where hot lava has dynamically interacted with unconsolidated aeolian sands. Such interaction could involve lava cascading down the front of dune faces, or active 'aa' style flow fronts 'bulldozing' into and oversteepening dune faces causing rapid influx of sand into the active flow front. Resulting breccia horizons have been found up to 5 m thick. Locally, the aeolian sand is baked to a quartzite by the hot lava. In contrast, on other surfaces, the lava leaves striations in the sand as it flows across it indicating local flow directions and less pronounced interaction. In places, wind ripples and topset beds are preserved on the stoss side of the dune indicating the passive nature of emplacement for some of the lava flows. Peperites are often thought to form due to the presence of water within the unconsolidated sediments that the juvenile magma comes into contact with. However, examples from arid environments demonstrate that peperite-forming processes are diverse and may not always require water. Therefore, it is suggested that the term peperite should be used to describe deposits consisting of sediments mixed with juvenile magmatic components where it is clear that there has been a dynamic interaction between the two. This leaves the presence, or lack, of water as an issue for interpreting the processes by which the peperite formed. © 2002 Elsevier Science B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LG.lavase
Keywords: Aeolian; Etendeka; Lava-sediment interaction; Namibia; Peperite

Leaky top seals - Evidence, rates and mechanisms - Kurtev, Kuncho; Böker, Ulf; Drews, Michael; Abrakasa, Selegha; Aplin, Andrew (3rd International Conference on Fault and Top Seals: From Characterization to Modelling, 2012)

Lernort Geologie - de Wall, Helga; et al. (Hrsg.: Bayerisches Staatsministerium für Umwelt und Gesundheit (StMUG), Staatsinstitut für Schulqualität und Bildungsforschung (ISB) & GeoZentrum Nordbayern der FAU Erlangen-Nürnberg (GZN), 2009)
UnivIS-Import:2017-11-07:Pub.2009.nat.dgeo.IGM.c3tekt.lernor

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, 2012)
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.lethal

Life's complexity cast in stone - Kießling, Wolfgang (Science, 2006)
UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.LP.lifesc

Limestone-marl alternations: A warm-water phenomenon? - Westphal, Hildegard; Munnecke, Axel (Geology, 2003)
Ancient limestone-marl alternations are concentrated in settings analogous to loci of aragonite accumulation in the modern world. They typically occur on shelves in the tropical-subtropical climate belt, are far more abundant on passive continental margins than on active ones, and are rare in upwelling zones. In recent studies, aragonite was proposed to play an important role in differential diagenesis typical of most limestone-marl alternations. The coincidence of depositional settings of ancient limestone-marl alternations and modern aragonite accumulation is a strong case for this hypothesis. If confirmed, it could provide a valuable tool for broad-scale paleoenvironmental interpretations. An additional, different type of limestone-marl alternations resulted from the Cretaceous explosion in productivity of calcitic plankton: these pelagic ones are fundamentally different in their style of diagenesi
Keywords: Aragonite; Differential diagenesis; Global maps; Limestone-marl alternations; Paleoenvironment; Rhythmites

Limestone - Marl alternations in epeiric sea settings - Witnesses of environmental changes or diagnesis? - Westphal, Hildegard; Munnecke, Axel; Böhm, Florian; Bornholdt, Stefan (2008)
Limestone-marl alternations are widespread and typical sediments of epeiric basins and are present in varying abundance throughout the Phanerozoic. In many cases, their rhythmic appearance has been interpreted as a direct response to orbital forcing. However, it is a challenge to unequivocally prove a sedimentary origin of the rhythmic intercalation of the two lithologies. This difficulty arises from differential diagenesis that alters calcareous beds in different ways than interlayers (marls), causing a loss of comparability between the final lithologies. Differential diagenesis, between other effects, causes passive enrichment of the inert non-carbonate fraction in interlayers, where calcium carbonate is dissolved, as well as passive dilution in limestone beds, which get cemented by imported calcium carbonate. Therefore, reliable information about primary systematic differences in the precursor sediments is preserved only in constituents that are not modified during diagenesis. Such diagenetically inert components include the spectra of organic-walled microfossils (but not their absolute concentration in the bulk sediment) and the ratios of certain trace elements (also not their absolute concentrations). Systematic differences in diagenetically inert components can provide unequivocal proof of primary differences. In the limestone-marl alternations, we have studied however, such aspects do not directly reflect the lithological rhythm, shedding doubt on limestone-marl alternations as direct archives of environmental change. Box-model computer simulations visualize possible effects of early diagenetic change acting on the precursors of limestone-marl alternations, independent of the presence or absence of a primary sedimentary rhythm. The simulations demonstrate that diagenesis has the potential to seriously distort any primary rhythm present in the pristine sediment. In particular, differential compaction acting mainly on the marl interlayers induces distortions of the ratios of the original frequencies. These simulations emphasize the difficulties in conducting frequency analyses on relative carbonate contents in real-world succession
Keywords: anactualism; aragonite; aragonite sea; calcite; calcite sea; cellular automaton; cementation; compaction; computer simulation; diagenesis; differential diagenesis; dissolution; distortion; environmental archive; environmental conditions; insolubles; limestone-marl alternation; Milankovitch; model; overprint; palynomorphs; sedimentary record; self- organization; stratigraphic record; rhythmites

Li/Mg systematics in scleractinian corals: Calibration of the thermometer - Montagna, Paolo; McCulloch, Malcolm; Douville, Eric; López Correa, Matthias; Trotter, Julie; Rodolfo-Metalpa, Ricardo; Dissard, Delphine; Ferrier-Pagès, Christine; Frank, Norbert; Freiwald, André; Goldstein, Steve; Mazzoli, Claudio; et al. (Geochimica Et Cosmochimica Acta, 2014)
We show that the Li/Mg systematics of a large suite of aragonitic coral skeletons, representing a wide range of species inhabiting disparate environments, provides a robust proxy for ambient seawater temperature. The corals encompass both zooxanthellate and azooxanthellate species (Acropora sp., Porites sp., Cladocora caespitosa, Lophelia pertusa, Madrepora oculata and Flabellum impensum) collected from shallow, intermediate, and deep-water habitats, as well as specimens cultured in tanks under temperature-controlled conditions. The Li/Mg ratios observed in corals from these diverse tropical, temperate, and deep-water environments are shown to be highly correlated with temperature, giving an exponential temperature relationship of: Li/Mg (mmol/mol)=5.41 exp (-0.049*T) (r2=0.975, n=49). Based on the standard error of the Li/Mg versus temperature correlation, we obtain a typical precision of ±0.9°C for the wide range of species analysed, similar or better than that of other less robust coral temperature proxies such as Sr/Ca ratios.The robustness and species independent character of the Li/Mg temperature proxy is shown to be the result of the normalization of Li to Mg, effectively eliminating the precipitation efficiency component such that temperature remains as the main controller of coral Li/Mg compositions. This is inferred from analysis of corresponding Li/Ca and Mg/Ca ratios with both ratios showing strong microstructure-related co-variations between the fibrous aragonite and centres of calcification, a characteristic that we attribute to varying physiological controls on growth rate. Furthermore, Li/Ca ratios show an offset between more rapidly growing zooxanthellate and azooxanthellate corals, and hence only an approximately inverse relationship to seawater temperature. Mg/Ca ratios show very strong physiological controls on growth rate but no significant dependence with temperature, except possibly for Acropora sp. and Porites sp. A strong positive correlation is nevertheless found between Li/Ca and Mg/Ca ratios at similar temperatures, indicating that both Li and Mg are subject to control by similar growth mechanisms, specifically the mass fraction of aragonite precipitated during calcification, which is shown to be consistent with a Rayleigh-based elemental fractionation model.The highly coherent array defined by Li/Mg versus temperature is thus largely independent of coral calcification mechanisms, with the strong temperature dependence reflecting the greater sensitivity of the Kd Li/Ca partition coefficient relative to Kd Mg/Ca. Accordingly, Li/Mg ratios exhibit a highly coherent exponential correlation with temperature, thereby providing a more robust tool for reconstructing paleo-seawater temperatures. © 2014 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LP.limgsy

Limited latitudinal mantle plume motion for the Louisville hotspot - Koppers, Anthony A. P.; Yamazaki, Toshitsugu; Geldmacher, Joerg; Gee, Jeffrey S.; Pressling, Nicola; Hoshi, Hiroyuki; Anderson, L.; Beier, Christoph; Buchs, D. M.; Chen, L-H.; Cohen, B. E.; Deschamps, Fabien; et al. (Nature Geoscience, 2012)
Hotspots that form above upwelling plumes of hot material from the deep mantle typically leave narrow trails of volcanic seamounts as a tectonic plate moves over their location. These seamount trails are excellent recorders of Earth's deep processes and allow us to untangle ancient mantle plume motions. During ascent it is likely that mantle plumes are pushed away from their vertical upwelling trajectories by mantle convection forces. It has been proposed that a large-scale lateral displacement, termed the mantle wind, existed in the Pacific between about 80 and 50 million years ago, and shifted the Hawaiian mantle plume southwards by about 15° of latitude. Here we use 40 Ar/ 39 Ar age dating and palaeomagnetic inclination data from four seamounts associated with the Louisville hotspot in the South Pacific Ocean to show that this hotspot has been relatively stable in terms of its location. Specifically, the Louisville hotspot - the southern hemisphere counterpart of Hawai'i - has remained within 3-5° of its present-day latitude of about 51° €‰S between 70 and 50 million years ago. Although we cannot exclude a more significant southward motion before that time, we suggest that the Louisville and Hawaiian hotspots are moving independently, and not as part of a large-scale mantle wind in the Pacific. © 2012 Macmillan Publishers Limited. All rights reserved.

Lithium and boron isotope systematics in lavas from the Azores islands reveal crustal assimilation - Genske, Felix; Turner, Simon P.; Beier, Christoph; Haase, Karsten; Chu, Mei-Fei; Tonarini, Sonja; Pearson, Norman J. (Chemical Geology, 2014)
The stable isotope systems of Li and B are useful tools for the understanding of ocean island basalt genesis. We have applied both systems to a comprehensive set of well-characterised samples across the Azores islands in order to further evaluate the nature of the mantle source. These ocean islands represent the surface expression of a low-buoyancy mantle plume. The variability of Li and B concentrations and their isotopic compositions across the archipelago builds on recent radiogenic isotope studies from the islands to the west of the Mid-Atlantic Ridge (Flores and Corvo). The results for both systems yield some values that are typical for ocean island basalts; however, the variability of both δLi and δB observed in primitive lavas is most extreme on the western islands of Flores and Corvo (δLi=+3.5 to +8.2‰ and δB=-3.5 to +11.8‰). The large spread in isotopic composition is most likely due to contamination of the magmas during ascent through hydrothermally altered oceanic crust. Models of assimilation fractional crystallisation best explain the variability observed on each island and allow for robust estimates of the mantle source. The implication of these observations is that the interpretation of the radiogenic isotopes and trace elements may have to be treated with care if the stable isotopes record contamination by assimilation of hydrothermally altered material and that the use of Li and B as mantle source tracers may be obscured by shallow level processes. Further, it seems unlikely that the large range observed in Sr and Nd isotopes can reflect variable contributions from recycled low-T materials such as sediment or altered MORB, since there is no correlation between the radiogenic and stable isotope data. © 2014 Elsevier B.V.
Keywords: Assimilation; Azores mantle plume; Lithium-Boron isotopes; Ocean island basalts; Recycling

Lithological and structural control of Hattian Bala rock avalanche triggered by the Kashmir earthquake 2005, sub-Himalayas, northern Pakistan - Basharat, Muhammad; Ehret, Dominik; Baig, Mirza Shahid; Rohn, Joachim (Journal of Earth Science, 2012)
Keywords: Kashmir earthquake 2005; mass movement; Muzaffarabad fault; northern Pakistan; rock avalanche

Lithological dependence of aragonite preservation in monospecific gastropod deposits of the Miocene Mainz Basin: Implications for the (dia-)genesis of limestone–marl alternations - Nohl, Theresa; Wetterich, Jannick; Fobbe, Nicholas; Munnecke, Axel (Journal of Sedimentary Research, 2020)

Lithologic, geomorphic, and climatic controls on sand generation from volcanic rocks in the Sierra Nevada de Santa Marta massif (NE Colombia) - Hatzenbühler, Diana; Caracciolo, Luca; Weltje, G. J.; Piraquive, A.; Regelous, Marcel (Sedimentary Geology, 2022)
Tectonics, climate, and lithology are the three main factors controlling the generation and transfer of sediments as well as their textural and compositional signatures. In this paper, we investigate the generation of sands from volcanic rocks in nine drainages with mixed lithological assemblage in a high-relief – subtropical climate setting (Sierra Nevada de Santa Marta, NE Colombia). The integration of geomorphological analysis with sand petrography, and bulk-rock and clay geochemistry allows us to constrain the dynamics regulating the generation of sediments derived from felsic and mafic-intermediate volcanic basement rocks in relation to plutonic and metamorphic lithologies. The petrographic composition of modern fluvial sands from the area is extremely variable (litho-feldspatho-quartzose, feldspatho-quartzose, and quartzose-feldspatho-lithic), but it reveals a strong dilution of (especially mafic) volcanic compositional signals, and a consequent overrepresentation of plutonic and metamorphic lithologies. Traditional chemical weathering indices fail to represent the extent of chemical alteration, but instead seem to favour preservation of provenance signals. Chemical weathering primarily affects feldspars and the ferromagnesian groundmass of mafic volcanic rock fragments. Enrichment of ferromagnesian elements in the clay fraction supports the notion that mafic volcanic rock fragments are unstable relative to plutonic and metamorphic rocks. Drainage features (particularly river network and relief) control the abundance of volcanic lithic fragments and the rates and extent of chemical weathering. A linear log-ratio model permits us to quantify sediment generation from volcanic rocks in this mixed-lithology setting. The results indicate that even in the case where volcanic grains are practically absent in the sand fraction, there could still be up to 20% of volcanic rocks in the drainage basin, and in the case that 50% of the sand grains are volcanic, around 75% of drained lithologies are expected to be volcanic. Our results demonstrate that the contribution of volcanic detritus to modern sands systematically underrepresents the areal proportion of volcanics rocks in mixed source areas. Post-depositional diagenetic modifications are likely to alter and/or dissolve volcanic lithic fragments, making accurate reconstruction of sediment provenance even more difficult. Sediment-generation models based on a range of mixed lithologies in various tectonic and climatic settings will be needed to improve estimates of the abundance of volcanic rocks in drainage basins of ancient sediment routing systems.
CRIS-Team Scopus Importer:2022-03-25
Keywords: Lithological; tectonic; and climatic controls; Quantitative provenance analysis; Sediment budget; Sediment generation; Weathering of volcanic rocks

Lithologierekonstruktion von submarinen Einheiten des Mauna Kea Vulkans mit bohrlochgeophysikalischen Messungen der magnetischen Suszeptibilität, HSDP Bohrung, Hawaii. - de Wall, Helga; et al. (11. Symposium "Tektonik, Struktur- und Kristallingeologie", 2006)
UnivIS-Import:2015-04-16:Pub.2006.nat.dgeo.IGM.c3tekt.lithol

LITHOLOGY CONTROLS AMMONOID SIZE DISTRIBUTIONS - de Baets, Kenneth; Jarochowska, Emilia; Buchwald, Stella Zora; Klug, Christian; Korn, Dieter (Palaios, 2022)
Body-size distributions of organisms across environments in space and time are a powerful source of information on ecological and evolutionary processes. However, most studies only focus on selected parameters of size distributions (e.g., central tendency or extremes) and rarely take into account entire distributions and how they are affected by the collection style and facies. Here we analyze the impact of facies, region, taxonomy, and collection style over size distributions using diameter as a proxy of Late Devonian ammonoids in their entirety using non-metric multidimensional scaling and PERMANOVA based on Kolmogorov distance. The effects are then compared with effects on mean sizes. In all analyses, lithology was the dominant effect, with sizes greater by 59% in marls and by 33% in limestones, as compared to black shales. The effect of complete sampling style was a decrease in size by 11%. Kurtosis was an important parameter differentiating size distributions, with platykurtic distributions in marls and leptokurtic distributions in limestones, suggesting that this parameter may reflect different degrees of time averaging. Most size distributions were positively skewed, but most strongly in marls. Complete sampling led to skewness values close to zero (symmetrical distributions) and high kurtosis.
CRIS-Team WoS Importer:2023-02-10

Lithology-specific influence of particle size distribution and mineralogical composition on thermal conductivity measurements of rock fragments - Kämmlein, Marion; Stollhofen, Harald (Geothermics, 2019)
Thermal conductivity data from reservoir rocks are key parameters for the analysis of heat transfer processes and heat flow patterns in geothermal exploration. Laboratory measurements of regional sample sets still provide the most reliable database. Since well cores are rarely available, rock fragments (e.g., drill cuttings) are the most common sample type for laboratory thermal conductivity measurements. However, the effects of the particle size of the rock fragments on the determination of thermal conductivity have not yet been discussed in a systematic study for different rock types. In this study, we used a line source device to investigate the influence of the particle size distribution of rock fragments and powder samples from different rock types on thermal conductivity measurements. The study focuses on three main objectives: <dl> 1. Does the particle size distribution of rock fragments impact thermal conductivity measurements of sample–water mixtures with a line source? 2. Are there lithology-specific differences in suitable particle sizes for measurements of thermal conductivity? 3. Is there an ‘ideal’ or an inappropriate particle size for measurements of rock fragments? </dl> Our study demonstrates that particle size effects on thermal conductivity determination of rock fragments and powders are unequivocal and that the accuracy of thermal conductivity determination can be improved by consideration of suitable, lithology-specific particle size ranges. The accuracy of measurement is related to the particle size distribution, mineralogical composition, competence under mechanical stress, and porosity of the sample–water mixtures during the measurement. For almost monomineralic limestones without significant clay volume fractions, powder samples with particle sizes ≤0.063 mm are most appropriate. In the case of argillaceous sandstone, powder samples are an inappropriate sample type, and instead, coarse rock fragment samples with mean particle sizes of 0.9–1.3 mm are recommended.
Keywords: Thermal conductivity; Particle size; Rock fragments; Mineralogical composition; Powder; Drill cuttings

Lithospheric control on geochemical composition along the Louisville Seamount Chain - Beier, Christoph; Vanderkluysen, Loyc; Regelous, Marcel; Mahoney, John J.; Garbe-Schoenberg, Dieter (Geochemistry Geophysics Geosystems, 2011)
Major and trace element and Sr, Nd, and Pb isotope data for lavas from 12 seamounts along the western (older) 1500 km section of the Louisville Seamount Chain in the southwest Pacific show remarkably uniform compositions over a ∼30-40 Myr period of volcanism. All 56 samples analyzed are alkalic to transitional in composition. Unlike Hawaiian volcanoes, Louisville volcanoes appear not to pass through a sequence of evolutionary stages characterized by older tholeiitic basalts overlain by incompatible element enriched alkalic and silica-undersaturated lavas. The youngest lavas from a given Louisville seamount tend to have the least enriched incompatible element compositions. This unusual chemical evolution may be the result of re-melting of heterogeneous hot spot mantle that was partially depleted during the earlier, age progressive stages. The oldest Louisville seamounts were constructed close to the extinct Osbourn Trough spreading center, located north of the chain, but age-progressive lavas from these older seamounts are not significantly different to lavas from younger seamounts. This may indicate that spreading at this fossil ridge ceased several tens of millions of years before the oldest Louisville seamounts were constructed. Large fracture zones apparently had no significant effects on the composition of Louisville magmatism. However, lavas from the central part of the Louisville Seamount Chain, where volcanoes are smaller and more widely spaced, tend to have more variable and more enriched compositions. We suggest this may reflect smaller degrees of melting resulting from greater lithosphere thickness, and hence a shorter melting column for this section of the Louisville Seamounts. © 2011 by the American Geophysical Union.
Keywords: lithosphere thickness; Louisville Seamount Chain; melting dynamics; plume evolution; spreading centre