Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms - Piatka, David; Frank, Alexander; Köhler, Inga; Castiglione, Kathrin; van Geldern, Robert; Barth, Johannes (Science of the Total Environment, 2021)
Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over a period of 23 months. This helped to map turnover and sources of aqueous carbon before, during, and after bloom events. During bloom events POC isotope values (δ13CPOC) increased up to −17.4‰, after aqueous CO2 (CO2(aq)) fell below an atmospheric equilibration value of 412 μatm. Additionally, carbon isotope enrichment between CO2(aq) and POC (εCO2-phyto) ranged from 2.0 to 21.5‰ with lowest fractionations observed at pH values above 8.9. The increase of δ13CPOC and decrease of εCO2-phyto values at low pCO2 and high pH was most likely caused by the activation of the carbon concentrating mechanism (CCM). This mechanism correlated with prevalent assimilation of 13C-enriched HCO3−. Surprisingly, CO2(aq) still contributed more than 50% to the POC pool down to pCO2 values of around 150 μatm. Only after this threshold the reduced εCO2-phyto suggested incorporation of 13C-enriched HCO3−.
CRIS-Team Scopus Importer:2021-11-05
Keywords: Aquatic carbon species; Carbon concentrating mechanism (CCM); Mixing model; Phytoplankton blooms; Pond water; Stable isotopes

Barkerina dobrogiaca Neagu, 2000, a Valanginian marker taxon from the northern Neotethysian margin - Schlagintweit, Felix; Bucur, Ioan I.; Granier, Bruno; Koch, Roman (Cretaceous Research, 2019)
Barkerina dobrogiaca Neagu (Valanginian of Romania), a medium-sized complex benthic foraminifera, is described from the Valanginian of the Pontides, NE Turkey. Barkerina dobrogiaca differs from the type-species B. barkerensis Frizzell & Schwartz (Albian of Texas) by its small size, and comparably thin septula and test wall. The present paper is a further contribution to the knowledge of inventory and faunal assemblages of Valanginian shallow-water carbonates. Compared to the classical Urgonian (Hauterivian to lower Aptian) these are still incompletely known. Together with another form reported from the Barremian of Romania, it also shows that representatives of Barkerina Frizzell & Schwartz are well present in the Neotethysian realm.
CRIS-Team Scopus Importer:2021-04-20
Keywords: Biostratigraphy; Early Cretaceous; Exoskeleton; Foraminiferida; Paleobiogeography; Systematics

Basaltic cognate enclaves from Dokdo Island as a window for intraplate mafic alkaline OIB magma dynamics in a back-arc basin - Park, Jongkyu; Lim, Hoseong; Myeong, Bora; Jang, Yun-Deuk; Brenna, Marco (Contributions To Mineralogy and Petrology, 2022)
Volcanoes with ocean island basalt (OIB)-like characteristics occur in all settings. Their origin is particularly enigmatic when they occur in close spatial and temporal association with subduction-related volcanism (e.g., back-arc basin basalts; BABB). A set of cognate enclaves and a late-intruding dike from Dokdo Island (Republic of Korea) were used to probe an intraplate mafic alkaline plumbing system developed in a back-arc basin. Detailed petrography, mineral chemistry, and whole-rock major- and trace-element geochemistry were combined with geothermobaro-hygrometric and whole-rock geochemical models. The cognate samples are defined as basalt-trachybasalt and gabbro, while a late-intruding dike has basaltic trachyandesite composition. In general, plagioclase crystals in the samples are classified as labradorite-bytownite, with cores richer in anorthite component compared to rims. Clinopyroxene crystals are sector-zoned diopside characterized by [2(IV)Si(4+) + Mg-VI(2+)](basal) <-> [2(IV)Al(3+) + Ti-VI(4+)](prism). The prism sector-based thermobarometric models suggest that the cognate enclaves may represent multi-stage magmatic conditions from near-source (> 1250 degrees C and 1.5 GPa) through underplating (similar to 1220 degrees C at similar to 640 MPa) to intermediate (similar to 1180 degrees C at similar to 400 MPa) stages. Shallow crustal stagnant conditions (similar to 1100 degrees C at similar to 120 MPa) are estimated from the late-intruding dike. Clinopyroxene- and plagioclase-based hygrometric models give a constant H2O abundance of similar to 1.5-2 wt% during the Dokdo basaltic magma evolution and ascent. According to our trace-element models, deep near-source parental melt may result from similar to 35% partial melting of hornblendite + spinel-peridotite and the associated mixing with clinopyroxene mush-derived 0.5% partial melt by a ratio of 0.6:0.4. From the parent, crystallization of up to 50% with the fractionating proportions of 0.7 plagioclase + 0.3 clinopyroxene can produce the whole compositional range of the Dokdo mafic alkaline magma. Rare or absent olivine in the early formed enclave may suggest that clinopyroxene and olivine are, respectively, crystallized at high and low pressure due to depressed olivine liquidus via melt compositional effect. We suggest that, during back-arc basin opening, BABB-related melt percolation into the extensional cracks in the lithospheric mantle and accompanying metasomatism provide hornblenditic source for the subsequent OIB magmatism.
CRIS-Team WoS Importer:2022-09-02

Basement structure and its influence on the structural configuration of the northern North Sea rift. - Fazli Khani, Hamed; Fossen, Haakon; Gawthorpe, Robert L.; Faleide, Jan Inge; Bell, Rebecca E.; et al. (Tectonics, 2017)

Basement structure in Eastern Egypt: quantitative perspectives for the second century - de Wall, Helga; et al. (1997)
UnivIS-Import:2015-03-05:Pub.1997.nat.dgeo.IGM.c3tekt.baseme

Bayesian analysis of biodiversity patterns via beam trawl versus video transect—a comparative case study of Svalbard rhodolith beds - Straube, Eileen; Neumann, Hermann; Wisshak, Max; Mathes, Gregor; Teichert, Sebastian (Biodiversity and Conservation, 2024)
Knowledge of spatial biodiversity patterns is important for ecosystem assessment. Rhodoliths, free-living calcareous algae, are biotic components that structure the sea floor through their complex calcareous skeletons and their tendency to accumulate in an area to form rhodolith beds. Thereby, rhodoliths are considered to act as ecosystem engineers promoting local biodiversity. In this study, the biodiversity of rhodolith beds in Mosselbukta, Svalbard, was investigated to analyse the proposed link between local biodiversity and the presence of rhodoliths by evaluating beam trawl and underwater video transect data. The comparative analysis of two sampling methods addressing the same research question allowed us to assess the suitability of these two methods. To test our hypothesis and the utility of the two methods, evaluations of the two data sets were carried out separately by using Bayesian statistics. The results confirm a positive relationship between the presence of rhodoliths and local biodiversity with a posterior probability of 70% for the video transects and 85% for the beam trawl data. The similarity of the results of the two methods suggests that both methods are well-suited for the analysis of local biodiversity patterns. The combination of the two methods, with their individual strengths and weaknesses, has provided stronger support for the results and a broader view on different components of the biodiversity in the Svalbard rhodolith beds.<br
Keywords: Arctic; method comparison; rhodoliths; quantitative analysis; crustose coralline algae

Bed II Sequence Stratigraphic context of EF-HR and HWK EE archaeological sites, and the Oldowan/Acheulean succession at Olduvai Gorge, Tanzania - Stanistreet, Ian G.; McHenry, Lindsay J.; Stollhofen, Harald; de la Torre, Ignacio (Journal of Human Evolution, 2018)
Archaeological excavations at EF-HR and HWK EE allow reassessment of Bed II stratigraphy within the Junction Area and eastern Olduvai Gorge. Application of Sequence Stratigraphic methods provides a time-stratigraphic framework enabling correlation of sedimentary units across facies boundaries, applicable even in those areas where conventional timelines, such as tephrostratigraphic markers, are absent, eroded, or reworked. Sequence Stratigraphically, Bed II subdivides into five major Sequences 1 to 5, all floored by major disconformities that incise deeply into the underlying succession, proving that simple "layer cake" stratigraphy is inappropriate. Previous establishment of the Lemuta Member has invalidated the use of Tuff IIA as the boundary between Lower and Middle Bed II, now redefined at the disconformity between Sequences 2 and 3, a lithostratigraphic contact underlying the succession containing the Lower, Middle, and Upper Augitic Sandstones. HWK EE site records Oldowan technology in the Lower Augitic Sandstone at the base of Sequence 3, within Middle Bed II. We suggest placement of recently reported Acheulean levels at FLK W within the Middle Augitic Sandstone, thus emphasizing that handaxes are yet to be found in earlier stratigraphic units of the Olduvai sequence. This would place a boundary between the Oldowan and Acheulean technologies at Olduvai in the Tuff IIB zone or earliest Middle Augitic Sandstone. A major disconformity between Sequences 3 and 4 at and near EF-HR cuts through the level of Tuff IIC, placing the main Acheulean EF-HR assemblage at the base of Sequence 4, within Upper rather than Middle Bed II. Sequence stratigraphic methods also yield a more highly resolved Bed II stratigraphic framework. Backwall and sidewall surveying of archaeological trenches at EF-HR and HWK EE permits definition of “Lake-parasequences” nested within the major Sequences that record downcutting of disconformities associated with lake regression, then sedimentation associated with lake transgression, capped finally by another erosional disconformity or hiatal paraconformity caused by the next lake withdrawal. On a relative time-scale rather than a vertical metre scale, the resulting Wheeler diagram framework provides a basis for recognizing time-equivalent depositional episodes and the position of time gaps at various scales. Relative timing of archaeological assemblage levels can then be differentiated at a millennial scale within this framewor
Keywords: Lake-parasequence; Oldowan/Acheulean succession; Bed II Olduvai Gorge; Geoarchaeology; Sequence Stratigraphy; Wheeler diagram

Beta-alumina and magnetoplumbite-type compounds in the systems CaO/SrO/BaO-Al2O3/Fe2O3-MgO - Göbbels, Matthias (Mineralogy for the New Millennium, 2002)
UnivIS-Import:2015-04-16:Pub.2002.nat.dgeo.IGM.LM.betaal

Beta diversity in Triassic and modern marine communities - Roden, Vanessa; Hausmann, Imelda M.; Zuschin, Martin; Kießling, Wolfgang (5th International Palaeontological Congress, 2018)

Beta diversity in Triassic and modern reef basin assemblages - Roden, Vanessa (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2020)

Between defects and inclusions: The fate of tellurium in pyrite - Börner, Frederik; Keith, Manuel; Fougerouse, Denis; Macauley, Chandra; Felfer, Peter; Yokosawa, Tadahiro; Apeleo Zubiri, Benjamin; Spiecker, Erdmann (Chemical Geology, 2023)
Tellurium (Te) is a critical commodity, essential for renewable energy technologies and other high-tech applications. Most Te is currently recovered from anode slimes, i.e., waste arising from copper refining. Rising demand and the key role for the green transition make the diversification and extension of the Te supply important. However, the nature of Te incorporation into ores is still poorly understood and hinders their economic potential. Here, we investigate the distribution of Te in pyrite from a high-grade Au-Ag-Te epithermal-type ore, where pyrite is already processed for ‘invisible’ Au, to inform metallurgical extraction methods, and secure future Te supply. Current models of Te incorporation into pyrite suggest a solid-solution limit in relation to As, similar as for ‘invisible’ Au. In this study, we identified three distinct modes of Te incorporation in pyrite, which challenge previous solubility models: (1) Te solid-solution, at concentrations (up to 285 ppma) that significantly exceed the previously suggested solubility limit. (2) Nano-telluride inclusions along cracks that formed by intra-grain remobilization. (3) Crystal defects, enriched in Te through pipe diffusion hosting up to 0.5 at. % Te. Our results therefore provide new fundamental insights into the chemical and structural coordination of Te in pyrite, which may guide future efforts for its direct recovery.<br
Keywords: Pyrite; Tellurium (Te); Atom probe tomography (APT); Low sulfidation epithermal; Solid solution; Inclusions; Defects; Vatukoula

Between defects and inclusions: The fate of tellurium in pyrite - Börner, Frederik; Keith, Manuel; Fougerouse, Denis; Macauley, Chandra; Felfer, Peter; Yokosawa, Tadahiro; Apeleo Zubiri, Benjamin; Spiecker, Erdmann (Chemical Geology, 2023)
Tellurium (Te) is a critical commodity, essential for renewable energy technologies and other high-tech applications. Most Te is currently recovered from anode slimes, i.e., waste arising from copper refining. Rising demand and the key role for the green transition make the diversification and extension of the Te supply important. However, the nature of Te incorporation into ores is still poorly understood and hinders their economic potential. Here, we investigate the distribution of Te in pyrite from a high-grade Au-Ag-Te epithermal-type ore, where pyrite is already processed for ‘invisible’ Au, to inform metallurgical extraction methods, and secure future Te supply. Current models of Te incorporation into pyrite suggest a solid-solution limit in relation to As, similar as for ‘invisible’ Au. In this study, we identified three distinct modes of Te incorporation in pyrite, which challenge previous solubility models: (1) Te solid-solution, at concentrations (up to 285 ppma) that significantly exceed the previously suggested solubility limit. (2) Nano-telluride inclusions along cracks that formed by intra-grain remobilization. (3) Crystal defects, enriched in Te through pipe diffusion hosting up to 0.5 at. % Te. Our results therefore provide new fundamental insights into the chemical and structural coordination of Te in pyrite, which may guide future efforts for its direct recovery.
CRIS-Team Scopus Importer:2023-09-01
Keywords: Atom probe tomography (APT); Defects; Inclusions; Low sulfidation epithermal; Pyrite; Solid solution; Tellurium (Te); Vatukoula

Between-taxon matching of common and rare species richness patterns - Reddin, Carl James; Bothwell, John; Lennon, Jack (Global Ecology and Biogeography, 2015)
Keywords: Indicator; Intertidal ecology; Marine; Rarity; Spatial; Species richness; Surrogacy

Bevocastria magna n. sp., eine neue Cyanobakterie aus den obertriassischen Riffkalken des Taurus-Gebirges (Türkei) - Senowbari-Daryan, Baba; Link, Michael (Palaeontologische Zeitschrift, 2004)
Bevocastria magna n. sp., an extremely large nodular species of the genus Bevocastria, is described from Upper Triassic (Norian) reef limestones of a locality south of the town of Dereköy (SW Antalya, Turkey). The nodule of B. magna looks like skeletons of chaetetid sponges which occur commonly at the same locality. B. magna is the first report of the genus from the Triassic deposits of Turkey.
UnivIS-Import:2015-04-14:Pub.2004.nat.dgeo.IGM.LP.bevoca
Keywords: Cyanobacteria; Bevocastria; n. sp.; Triassic; Norian; Taurus-Mts.; Turkey

Beware of effects on isotopes of dissolved oxygen during storage of natural iron-rich water samples: A technical note - Köhler, Inga; Piatka, David; Barth, Johannes; Martinez, Raul E. (Rapid Communications in Mass Spectrometry, 2021)
Rationale: Investigations of the isotope ratios of dissolved oxygen (δ18ODO) provide valuable information about the oxygen cycle in aquatic systems. However, oxidation of Fe(II) may change pristine δ18ODO values during storage and can lead to a misinterpretation. We sampled an Fe(II)-rich spring system and measured δ18ODO values at various time intervals in order to determine influences of Fe-oxidation. Methods: Water samples were collected from an Fe-rich spring and related stream and the δ18ODO values were measured in fresh, 4- and 13-day-old samples with an isotope ratio mass spectrometer. Three replicates were measured for each sample with a 1σ of ± 0.2‰. On-site parameters and Fe(II) contents were also measured over the course of the spring system by multi-parameter probes and spectrophotometry. Results: The δ18ODO values over the course of the spring system in fresh, 4- and 13-day-old samples revealed differences of up to 8‰. We explain this increase by the consumption of DO by Fe(II)-oxidation. After a flow length of 85 m the differences in δ18ODO values between fresh and older samples decreased because most of the Fe(II) was consumed. Conclusions: False interpretations of δ18ODO values are possible if Fe-rich water samples are measured after too long storage, and we recommend measurement immediately after sampling.
CRIS-Team Scopus Importer:2021-02-26

Biased preservation of Pleistocene climate variability proxies at Olduvai Gorge, Tanzania - Ferland, Troy M.; Colcord, Devon E.; Shilling, Andrea M.; Brassell, Simon C.; Stanistreet, Ian G.; Stollhofen, Harald; Njau, Jackson K.; Schick, Kathy D.; Toth, Nicholas; Freeman, Katherine H. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2021)
Olduvai Gorge in northern Tanzania contains a fossiliferous, well-characterized Pleistocene sedimentary record and provides the opportunity to study the relationships between a changing climate, ecology, and hominin evolution. The Olduvai Gorge Coring Project drilled four cores (1A, 2A, 3A, and 3B) into the depocenter of Paleolake Olduvai in 2014 to achieve increased temporal resolution of local climate and ecological data, and investigate the influence and timing of regional climate and tectonics on local signals. We present high-resolution records of bulk organic carbon isotopes (δ13Corg, ‰) from Cores 2A and 3A, total organic carbon (wt%) from Cores 2A and 3A, and organic carbon‑nitrogen ratios (C:N) from Core 2A. Previous work at Olduvai linked % TOC and δ13Corg to orbitally paced variations in lake depth and ecosystem dynamics from Upper Bed I and Lower Bed II (1.9–1.7 Ma), associated with eccentricity maxima and the presence of a perennial saline-alkaline lake in the basin. Bulk organic geochemical properties in both cores exhibit marked shifts in variance and magnitude at 1.9 and 1.7 Ma. Low % TOC values prior to and following 1.9–1.7 Ma implicate low productivity and/or increased degradation of organic matter, while C:N ratios from Core 2A reflect increased aquatic or bacterial input. Within the 1.9 to 1.7 Ma interval, high % TOC is dominated by terrestrial inputs as evidenced by high C:N ratios, and bulk δ13Corg captures high variability C3–C4 ecosystem dynamics. Climate variability is highest from 1.9–1.7 Ma, but the δ13Corg records are not consistent between Core 2A and Core 3A. From 1.9–1.7 Ma, Core 3A has increased indicators of erosion relative to Core 2A, suggesting a sedimentary aliasing of the δ13Corg record in Core 3A. Outside of the 1.9–1.7 Ma interval, both changes in organic carbon source and preferential preservation of proxies for wet conditions may obscure true climate variability, inviting further investigation into the ability of the Olduvai Gorge sedimentary record to test climate variability hypotheses for hominin evolutionary events.
CRIS-Team Scopus Importer:2021-01-08
Keywords: Bulk organic carbon isotopes; East Africa; Mean-variance changepoint detection; Pleistocene climate

Bibliographie der Geologischen Blätter für Nordost-Bayern - Baier, Alfons; Schulbert, Christian (Geologische Blätter für Nordost-Bayern und angrenzende Gebiete, 2011)
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LAG.biblio

Bicoelia corticifera, a new inozoid sponge from the Upper Triassic (Norian) reef boulders of Taurus Mountains (South Turkey) - Senowbari-Daryan, Baba; Link, Michael (Turkish Journal of Earth Sciences, 2014)
Upper Triassic Norian reef boulders, exposed in a locality in the Central Taurids, southern Turkey, yielded a high number of hypercalcified sponges, including Sphinctozoans, Inozoans, Spongiomorphids, and Chaetetids. The reef boulders are exposed near the fountain Tavuk Çeşme, located at the road leading from the town of Aksu to Yenişarbademli. Geologically this locality belongs to the Anamas Akseki Autochthon. In this paper a new inozoan sponge, Bicoelia corticifera nov. sp., is described from Tavuk Çeşme. It is a cylindrical and unbranched sponge, found in several thin sections. The sponge is characterized by 2 axial spongocoels, and the sponge wall is composed of fine reticulate fiber skeleton and a distinct outer wall. Usually several specimens grow closely side by side.
UnivIS-Import:2015-04-14:Pub.2014.nat.dgeo.IGM.LP.bicoel
Keywords: Sponge; Inozoa; Bicoelia; Triassic; Norian; reef; Central Taurids; Taurus Mountains; Turkey

BioDeepTime: A database of biodiversity time series for modern and fossil assemblages - Smith, Jansen; Rillo, Marina C.; Kocsis, Ádám; Dornelas, Maria; Fastovich, David; Huang, Huai Hsuan M.; Jonkers, Lukas; Kießling, Wolfgang; Li, Qijian; Liow, Lee Hsiang; Margulis-Ohnuma, Miranda; Meyers, Stephen; et al. (Global Ecology and Biogeography, 2023)
Motivation: We have little understanding of how communities respond to varying magnitudes and rates of environmental perturbations across temporal scales. BioDeepTime harmonizes assemblage time series of presence and abundance data to help facilitate investigations of community dynamics across timescales and the response of communities to natural and anthropogenic stressors. BioDeepTime includes time series of terrestrial and aquatic assemblages of varying spatial and temporal grain and extent from the present-day to millions of years ago. Main Types of Variables Included: BioDeepTime currently contains 7,437,847 taxon records from 10,062 assemblage time series, each with a minimum of 10 time steps. Age constraints, sampling method, environment and taxonomic scope are provided for each time series. Spatial Location and Grain: The database includes 8752 unique sampling locations from freshwater, marine and terrestrial ecosystems. Spatial grain represented by individual samples varies from quadrats on the order of several cm2 to grid cells of 100 km2. Time Period and Grain: BioDeepTime in aggregate currently spans the last 451 million years, with the 10,062 modern and fossil assemblage time series ranging in extent from years to millions of years. The median extent of modern time series is 18.7 years and for fossil series is 54,872 years. Temporal grain, the time encompassed by individual samples, ranges from days to tens of thousands of years. Major Taxa and Level of Measurement: The database contains information on 28,777 unique taxa with 4,769,789 records at the species level and another 271,218 records known to the genus level, including time series of benthic and planktonic foraminifera, coccolithophores, diatoms, ostracods, plants (pollen), radiolarians and other invertebrates and vertebrates. There are to date 7012 modern and 3050 fossil time series in BioDeepTime. Software Format: SQLite, Comma-separated values.
CRIS-Team Scopus Importer:2023-08-04
Keywords: deep-time; global; palaeobiology; species richness; temporal; timescale; turnover

Biodetrital carbonates on the Adriatic continental shelf imprinted by oxidation of seeping hydrocarbons - Taviani, Marco; Franchi, Fulvio; Angeletti, Lorenzo; Correggiari, Anna Maria; López Correa, Matthias; Masselli, Vittorio; Mazzoli, Claudio; Peckmann, Jörn (Marine and Petroleum Geology, 2015)
The gas-productive Bonaccia area located at ca. 80-90 m below sea level offshore Ancona (Central Adriatic Sea) is site of hydrocarbon-derived carbonate production. The carbonates include large dm-sized slabs (bryozoan limestone), smaller concretionary aggregates, mudstones and pipes. The mudstones and botryoidal aragonite cements within limestones show δ13C values as low as -47.8‰ VPDB, consistent with seepage of isotopically light hydrocarbons (e.g. methane). These hydrocarbon-derived carbonates commonly incorporate abundant shell remains, deriving from the prevalently coarse bioclastic-rich muddy deposits from post-glacial transgressive units. It is, therefore, hypothesized that hydrocarbon-rich fluids permeated the post-glacial sediments, resulting in seafloor seeps that were inhabited by chemosymbiotic lucinid bivalves and burrowing callianassid shrimps; fossils and traces of which have been found in the Bonaccia carbonates. Microbial oxidation of the reduced compounds contained in the seep fluids led to a locally patchy carbonate cementation of the sediments at the seep sites. The pipes are interpreted as decapod burrows that subsequently served as conduits for hydrocarbon leakage. Seepage is probably still active at present as testified by gas production at the study site. Interestingly, seep carbonates exhumed by erosion served as hard substrate for fouling benthos (i.e., bryozoans, oysters and red algae) in the Holocene. The main products of the processes at the Bonaccia study site are composite bryozoan-dominated limestones, whose multi-step and complex history was unfold thank to radiocarbon dating of key components and precise stratigraphic control. The Bonaccia case-study can serve as a model for the interpretation of ancient analogs, such as bryozoan dominated limestones and mudstones of Paleozoic to Mesozoic age, which are not uncommon in the geological record. It further calls for caution in assuming that the presence of dominant macrobenthic fossil in old hydrocarbon-derived limestones implies its ecological connection to active seepage.
UnivIS-Import:2016-06-01:Pub.2015.nat.dgeo.IGM.LP.biodet
Keywords: Adriatic sea; Cold-seep carbonates; Hydrocarbons; Quaternary

Biodiversity and Host–Parasite (Co)Extinction - van Dijk, Jeroen; de Baets, Kenneth (The Evolution and Fossil Record of Parasitism, 2021)
Parasitism is one of the most common modes of life, and yet it is often disregarded or ignored in nature conservation. We are at the brink of the sixth mass extinction and in order to assess the extinction risk of both parasites and their hosts, we first need to fully understand the role and function of parasites in ecosystems. Parasites might play an active role in their host’s extinction, and coextinction has been postulated to be the most common mode of extinction. However, parasites may be able to survive their host’s extinction through host switching, perhaps to a more abundant host, for example. The dilution effect has been described as an important natural defense mechanism for the host: higher biodiversity is associated with lower infection risk. Discussed here is the importance of biodiversity and host–parasite associations and (co)extinction, and the role the fossil record has in filling the knowledge gap regarding deep-time host–parasite interactions.
Keywords: Biodiversity; Co-extinction; Dilution effect; Host–parasite associations; Fossil record; Host switching

Biodiversity and palaeoecology of a marine basinal fauna from Misurina (Late Triassic Cassian Formation, Italy) - Hausmann, Imelda M.; Nützel, Alexander; Roden, Vanessa (88th Annual Conference of the Paläontologische Gesellschaft, 2017)

Biodiversity dynamics and environmental occupancy of fossil azooxanthellate and zooxanthellate scleractinian corals - Kießling, Wolfgang; Kocsis, Ádám (Paleobiology, 2015)
Scleractinian corals have two fundamentally different life strategies, which can be inferred from morphological criteria in fossil material. In the non-photosymbiotic group nutrition comes exclusively from heterotrophic feeding, whereas the photosymbiotic group achieves a good part of its nutrition from algae hosted in the coral's tissue. These ecologic differences arose early in the evolutionary history of corals but with repeated evolutionary losses and presumably also gains of symbiosis since then. We assessed the biodiversity dynamics and environmental occupancy of both ecologic groups to identify times when the evolutionary losses of symbiosis as inferred from molecular analyses might have occurred and if these can be linked to environmental change. Two episodes are likely: The first was in the mid-Cretaceous when non-symbiotic corals experienced an origination pulse and started to become more common in deeper, non-reef habitats and on siliciclastic substrates initiating a long-term offshore trend in occupancy. The second was around the Cretaceous/Paleogene boundary with another origination pulse and increased occupancy of deep-water settings in the non-symbiotic group. Environmental factors such as rapid global warming associated with mid-Cretaceous anoxic events and increased nutrient concentrations in Late Cretaceous-Cenozoic deeper waters are plausible mechanisms for the shift. Turnover rates and durations are not significantly different between the two ecologic groups when compared over the entire history of scleractinians. However, the deep-water shift of non-symbiotic corals was accompanied by reduced extinction rates, supporting the view that environmental occupancy is a prominent driver of evolutionary rates. ©
UnivIS-Import:2015-07-08:Pub.2015.nat.dgeo.IGM.LP.biodiv

Biodiversity patterns across the Late Paleozoic Ice Age - Seuß, Barbara; Roden, Vanessa; Kocsis, Ádám (Palaeontologia Electronica, 2020)

Biodiversity research: data without theory – theory without data - Rillig, Matthias C.; Kießling, Wolfgang; Borsch, Thomas; Gessler, Arthur; Greenwood, Alex D.; Hofer, Heribert; Joshi, Jasmin; Schröder, Boris; Thonicke, Kirsten; Tockner, Klement; Weisshuhn, Karoline; Jeltsch, Florian (Frontiers in Ecology and Evolution, 2015)
Keywords: Biodiversity; Ecology

Bioerosion in fossil cephalopods - a case study from the Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma, USA - Seuß, Barbara; Nützel, Alexander (Facies, 2019)
The Mid-Pennsylvanian (Desmoinesian-Virgilian) deposits from the Buckhorn Asphalt Quarry Lagerstätte near Sulphur, Oklahoma, are characterized by siliciclasticcarbonate rocks. One of these deposits is the 'cephalopod coquina' that contains a large amount of orthocerid and coiled nautiloid, and ammonoid shell remains. These were used for a detailed study on bioerosion in cephalopod shells in order to help in the reconstruction of the paleoenvironment and to increase the general knowledge on bioerosion in fossil cephalopods. More than 50 shell fragments were cast and investigated. The shells cast and investigated in this study comprise a diverse set of ichnotaxa-/forms. Besides chlorophyte and cyanobacterial traces, also rhodophyte, fungal and spongal traces are present as well as those of unknown origin. In addition, there are six ichnoforms that might have foraminiferans as producers. In orthoceratids, Ichnoreticulina elegans and a curly morphotype of Scolecia isp. are most common while the abundance in coiled cephalopods is dominated by the 'superthin form', the 'extremely thin form', and Flagrichnus profundus. In total twenty-two ichnotaxa and - forms were recognized and twelve of these have their oldest record in the Carboniferous. The succession of ichnotaxa/-forms in the casts of orthocones suggests deposition in the deep euphotic to dysphotic zone of the Buckhorn sea while shells of coiled specimens had drifted for a while; they were therefore more prone to bioerosion by autotrophs until they sank to the seafloor.<br
Keywords: Nautiloidea; ammonoidea; Bioerosion; fossil record; shells; bathymetry

Bioerosion in shells of modern Nautilus - Results from the investigation of live caught specimens - Seuß, Barbara; Wisshak, Max; Mapes, Royal H.; Landman, Neil (9th International Symposium 'Cephalopods present and past, 2014)
Over the past 20 years, Royal H. Mapes a nd colleagues caught specimens of the living Nautilus in various regions of the Southern Pacific Ocean. Many of these shells were encrusted by epiliths (foraminiferans, ostracods, goose barnacles). Additionally, the shells showed strong signs of bioerosion, i.e. numerous small irregular holes penetrating deep into the shell. Because bioerosion is a major factor in the degradation of carbonate skeletal material a study was carried out on four shells (one specimen of N. pompilius from Vanuatu, three specimens of N. macromphalus from New Caledonia) to investigate these holes in detail. The shells were broken into pieces and a set of epoxy resin casts was prepared for analyses with the scanning electron microscope. The analyses revealed that the small holes are the openings of two, so far undescribed, microbioerosion traces which are most likely produced by naked foraminiferans. Traces of these foraminiferans commonly occur in dense clusters in the shell of up to many dozen individuals. Because these traces were not reported from other substrates before, we conclude, that these boring naked foraminiferans are host specific. In addition to the two boring foraminiferans we found two further traces on the shells outside of Nautilus. These etchings derive from test-bearing foraminiferans, likely from some genera of the Rosalinidae. As of now, there is no indication that any of the foraminiferans, naked or with a test, were parasitic but instead they used the Nautilus shells as substrate to settle respectively to live in. Our study presents the first report on syn-vivo bioerosion in Nautilus shells and demonstrates that shell degradation in Nautilus already starts during lifetime of the cephalopo

Bioerosion in shells of modern Nautilus - Taphonomy of deep-marine versus backshore collected Nautilus macromphalus conchs (New Caledonia); 2014) - Seuß, Barbara (9th International Symposium 'Cephalopods present and past', 2014)
During field trips and research cruises into the New Caledonia region numerous shells of Nautilus macromphalus were collected by Royal H. Mapes and colleagues. On six of the shells a bioerosion study was carried out. Specimens: Four of the specimens derive from a backshore collection (AMNH 97753-56) on beaches on the island of Lifou. The shells were initially deposited in the shallow water and transported onto the beaches by waves and currents. Some specimens are heavily encrusted by non-calcareous and calcareous algae, bryozoans, serpulids, etc. and have largely lost their brownish-red color stripes while others are well-preserved and still display sharp reddish-brown color stripes and are only slightly encrusted.The second set of specimens are two deep-water dredged shells (AMNH 55916, -20). One shell derives from a setting half way from Grand Terre and the Isle of Pines and was collected in 395m water depth. The second shell was collected in 598m water depth at the Lansdowne Bank. Both shells are broken and highly abraded. Bioerosion: Bioerosion is defined as "the removal of consolidated mineral or lithic substrate by the direct action of organisms” (Neumann 1966) and is a combination of mechanical and chemical processes that destroy inorganic and biogenic carbonate. All of the shells show intensive signs of bioerosion. A detailed study was carried out to investigate the ichnocoenosis, i.e., the assemblages of ichnotaxa. ff. https://www.researchgate.net/publication/274667678_Bioerosion_in_shells_of_modern_Nautilus_-_Taphonomy_of_deep-marine_versus_backshore_collected_Nautilus_macromphalus_conchs_New_Caledonia_2014<br

Biogeochemical analysis of the calcification patterns of cold-water corals Madrepora oculata and Lophelia pertusa along contact surfaces with calcified tubes of the symbiotic polychaete Eunice norvegica: evaluation of a mucus calcification hypothesis - Oppelt, Alexandra; López Correa, Matthias; Rocha, Carlos (Deep-Sea Research Part I-Oceanographic Research Papers, 2017)
<span style="color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">The scleractinian cold-water corals (CWCs), including the species <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">Madrepora oculata<span style="color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;"> and especially <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">Lophelia pertusa<span style="color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">, have been studied extensively in an attempt to decipher environmental signals recorded during biomineralisation in order to extract environmental chronologies. However, understanding the mechanisms of carbonate precipitation is a prerequisite to interpret variations in geochemical signatures locked into the skeleton during coral growth; to date results are still inconclusive. Here a novel approach, comparing the calcification patterns within the coral microstructure of species <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">L. pertusa<span style="color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;"> and <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">M. oculata<span style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;"> and the geochemistry along the contact surfaces with calcified polychaete tubes is undertaken to provide additional information on the mechanisms of biomineralisation in colonial corals. The fact that no significant difference in microstructures, variations in growth rate, or geochemical composition between the corallite theca and the calcified polychaete tube was detectable leads to the conclusion that both have been deposited by the coral tissue in <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">L. pertusa<span style="color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;"> and <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">M. oculata<span style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">. Based on prior knowledge on the symbiotic relationship between CWCs and the polychaete <em style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;">Eunice norvegica,<span style="box-sizing: border-box; color: rgb(80, 80, 80); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: medium;"> an involvement of mucus in the calcification of the parchment tubes had been suspected. However, we found only evidence for aragonite precipitated by coral tissue, without evidence for an involvement of mucus in the calcification.
UnivIS-Import:2017-11-06:Pub.2017.nat.dgeo.IGM.LP.biogeo
Keywords: Biomineralization; Eunice norvegica; Lophelia pertusa; Madrepora oculata; Mucus calcification; Symbiosis

Biogeochemical evidence for environmental changes of Pleistocene Lake Olduvai during the transitional sequence of OGCP core 2A that encompasses Tuff IB ( 1.848 Ma) - Shilling, Andrea M.; Colcord, Devon E.; Karty, Jonathan; Hansen, Angela; Freeman, Katherine H.; Njau, Jackson K.; Stanistreet, Ian G.; Stollhofen, Harald; Schick, Kathy D.; Toth, Nicholas; Brassell, Simon C. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2019)
Olduvai Gorge is renowned for discoveries of hominin fossils and tools in a well-resolved sedimentary context, representing one of the foremost sites in East Africa that has afforded critical evidence of hominin evolution. In 2014, the Olduvai Gorge Coring Project (OGCP) recovered the first deep sediment cores from this location. These cores provide the first opportunity to examine an extensive stratigraphic record from one location and independent of the weathering and related degradation typical of outcrop samples. Samples from these cores have been correlated to Bed I tuffs and basalt marker beds that are well characterized from outcrops within the gorge. This study focuses on the biogeochemical investigation of a 10 m segment from OGCP sediment core 2A, where age constraints indicate deposition occurred over 50,000 years (from 1.8055 ± 0.003 Ma to 1.8551 ± 0.013 Ma). The segment includes Tuff IB and IF, which were deposited at a time that prior research indicates represents marked changes in the paleoenvironment at Olduvai, with indications that Paleolake Olduvai may have been completely desiccated by the time Tuff IF was deposited. This environmental change is recorded by the composition of sedimentary organic matter (OM) in terms of bulk organic geochemical properties observed as a decrease in % TOC and δ13Corg. In addition, temporal variations in source-specific biomarkers (n-alkanes, phytane, steradienes, A-norsteranes and alkenones) reflect a shift from a deeper lake setting with a prevalence of aquatic-sourced OM combined with input from terrestrial plant waxes to a more shallow, perennial lake where evidence of burrows and erosional surfaces is associated with microbially degraded OM and intermittent aquatic biomarkers. Thus, variations in biogeochemical proxies complement the sedimentological evidence confirming increased periods of prolonged desiccation of Paleolake Olduvai beginning around the time of Tuff IB deposition.
CRIS-Team Scopus Importer:2019-08-02
Keywords: Biomarkers; East Africa; n-Alkanes; Preservation; Tanzania

Biogeochemical evidence from OGCP Core 2A sediments for environmental changes preceding deposition of Tuff IB and climatic transitions in Upper Bed I of the Olduvai Basin - Shilling, Andrea M.; Colcord, Devon E.; Karty, Jonathan; Hansen, Angela; Freeman, Katherine H.; Njau, Jackson K.; Stanistreet, Ian G.; Stollhofen, Harald; Schick, Kathy D.; Toth, Nicholas; Brassell, Simon C. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2020)
Sediment cores recovered by the Olduvai Gorge Coring Project (OGCP) in 2014 afford the opportunity to examine the coupling of biogeochemical evidence for climatic and environmental change within the context of hominin evolution at this renowned East African locality. Investigations of elemental (total organic carbon – TOC or Corg wt%, carbon to nitrogen ratio - C/N), molecular (source-specific biomarkers), and isotopic (δ13Corg, δ2HnC31) compositions of organic matter provide evidence for temporal changes in sedimentary materials derived from terrestrial plants (C3, C4) and aquatic producers (algae, sponges, cyanobacteria), and in precipitation. The 13 kyr record of Upper Bed I immediately preceding Tuff IB extends high-resolution stratigraphic profiles of precession-scale alternations of wetter and drier conditions to encompass the entire interval from the Bed I Basalt to Tuff IB. The second wetter interval, designated W2, records local influences on climate and water supply consistent with evidence for discrete sediment sources based its physical properties (e.g., gamma radiation, magnetic susceptibility) compared with the overall sequence. The δ13CTOC values for wetter interval W2 reveal two millennial-scale ( 2.5 kyr) drier episodes followed by a shift in the dominance of C3 over C4 plants accompanying the transition to a drier climate (D3). Moreover, biogeochemical data for Upper Bed I show that changes from drier to wetter conditions occur more rapidly ( 900 yr) than wetter to drier transitions (>2.6 kyr), based on interpolated ages. In addition, biomarker profiles indicate that aquatic plants, primarily algae and macrophytes, may have been subject to more profound and faster fluctuations than variations in terrestrial vegetation expressed in terms of the relative proportions of woodland and grassland settings. Thus, environmental and climatic changes not only influenced the availability of resources of food and shelter for hominins within the Olduvai region but also led to their variation on centennial to millennial to precessional timescales.
CRIS-Team Scopus Importer:2020-07-24
Keywords: Biomarkers; EARS; n-alkanes; Paleoclimate; Tanzania

Biogeochemical formation of calyx-shaped carbonate crystal fans in the subsurface of the Early Triassic seafloor - Heindel, Katrin; Richoz, Sylvain; Birgel, Daniel; Brandner, Rainer; Klügel, Andreas; Krystyn, Leopold; Baud, Aymon; Horacek, Micha; Mohtat, Tayebeh; Peckmann, Joern (Gondwana Research, 2015)
Keywords: Diagenetic carbonate; End-Permian extinction; Lipid biomarkers; Rare earth elements; Subseafloor

Biogeographical distribution of Hyrrokkin (Rosalinidae, Foraminifera) and its host-specific morphological and textural trace variability - Beuck, Lydia; López Correa, Matthias; Freiwald, André (Current Developments in Bioerosion, 2008)
The parasitic foraminifer Hyrrokkin sarcophaga predominantly infests the cold-water coral Lophelia pertusa and the co-occurring bivalve Acesta excavata, showing a commensal or parasitic behaviour. It occurs also on some other corals (e.g., Caryophyllia sarsiae), bivalves (e.g., Delectopecten vitreus) and sponges (Geodia sp.), typically in aphotic environments. The aim of the study is to describe its traces from various host substrates, to characterise its parasitic behaviour and to map the geographical distribution of the genus Hyrrokkin. Epoxy-resin casts of H. sarcophaga traces in A. excavata, C. sarsiae, D. vitreus and L. pertusa, and of H. carnivora traces in A. excavata, were SEM analysed. The boring pattern is in all cases characterised by a shallow groove of up to 7 mm in diameter (max. 2 mm deep), from which 'whip'-shaped extensions protrude vertically into the substrate. In A. excavata the foraminifer can penetrate the entire valve to the mantle cavity, producing a thick shaft of fused 'whips'. This parasitic attack is answered by a strong callus formation of the mollusc. One individual foraminifer can repeatedly bypass the organic-rich callus, resulting in a thick aragonite pinnacle. The trace surface texture is xenoglyph and changes with the penetrated host-microstructures. This is especially obvious on deeply penetrating trace portions (e.g., 'whip'-shaped filaments) and is a strong indication for a chemical penetration mode (etching). The trace of Hyrrokkin is described as Kardopomorphos polydioryx igen. n., isp. n. On the substrates without the shaft, related to parasitic behaviour, Hyrrokkin might feed directly on adjacent external host tissue. H. sarcophaga is known along the North Atlantic continental margin from polar to subtropical latitudes and H. carnivora occurs on the continental margin of Mauritania, Congo and Guinea. In the Mediterranean we could document the parasitism of H. sarcophaga from Last Glacial A. excavata. Traces or detached foraminifer tests occur in Early Pleistocene cold-water coral deposits on Sicily and Rhodes. Recent H. sarcophaga has not been observed above 11°C and is scarce near 5°C water temperature. Hyrrokkin sp. was reported from the Canadian Pacific on fossil sponges and was observed on Acesta patagonica in the Beagle Channel (Chile). © 2008 Springer-Verlag Berlin Heidelberg.
UnivIS-Import:2015-04-16:Pub.2008.nat.dgeo.IGM.LP.biogeo
Keywords: Acesta; Bioerosion; Cold-water corals; Foraminifer; Hyrrokkin; Lophelia; Parasitism

Biogeographic ranges do not support niche theory in radiating Canary Island plant clades - Steinbauer, Manuel; Field, Richard; Mara Fernandez-Palacios, Jose; Irl, Severin D. H.; Otto, Rudiger; Schaefer, Hanno; Beierkuhnlein, Carl (Global Ecology and Biogeography, 2016)
Keywords: Adaptive radiation; climate; competition; divergence; ecological character displacement; endemic plants; ghost of competition past; niche conservatism; sister clades; speciation

Biogeography of Paleozoic Ammonoids - Korn, Dieter; de Baets, Kenneth (Ammonoid Paleobiology: From macroevolution to paleogeography, 2015)

Bioinspired Design of SrAl2O4:Eu2+ Phosphor - Kostova, Marya H.; Zollfrank, Cordt; Batentschuk, Miroslaw; Götz-Neunhoeffer, Friedlinde; Winnacker, Albrecht; Greil, Peter (Advanced Functional Materials, 2009)
A phosphor based on Sr0.97Al2O4:Eu 0.03 with a biomorphous morphology is manufactured via vacuum assisted infiltration of wood tissue [Pinus sylvestris) with a precursor nitrate solution. The nitrate solution penetrates homogeneously into the uniform arrangement of rectangular shaped tracheidal cells of the wood tissue. According to scanning electron microscopy, the original wood cell walls are completely transformed retaining the original wood structure. The major crystalline phase is monoclinic SrAl2O4, detected by X-ray diffraction and confirmed by Rietveld refinement. Energy-dispersive X-ray analysis proves the homogeneous conversion of the original wood cell wall into Sr 0.97Al2O4:Eu0.03 struts. The optical properties of the resulting phosphor material are determined by photoluminescence and cathode-luminescence spectroscopy in scanning electron microscopy. The biotemplated Sr0.97Al2O 4IEU0.03 shows a characteristic green emission at 530 nm (2.34 eV). Shaping biomorphous SrAl2O4:Eu2+ phosphor with a microstructure pseudomorphous to the bioorganic template anatomy offers a novel approach for designing micropatterned phosphor materials. © 2009 WILEY-VCH Verlag GmbH & Co. KCa
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LM.bioins

Bioluminescence in deep-sea isidid gorgonians from the Cape Verde archipelago - Raddatz, Jacek; López Correa, Matthias; Rüggeberg, Andres; Dullo, Wolf-Christian; Hansteen, Thor (Coral Reefs, 2011)
Cold-water corals, and in particular numerous gorgonian species, occur abundantly on the deep slopes of the Cape Verde archipelago (Fig. 1a). Among them, the isidid gorgonian genus Keratoisis occurred frequently. A living Keratoisis sp. was ROV collected (KIEL 6000) from 3,052 m (1642.3¢N, 2534.9¢W) in the Charles Darwin Volcanic Field (1b) during METEOR cruise M80/3. A strong luminescence was accidentally observed when this bamboo coral arrived on deck in the early evening hours just before sunset. The entire stem and branch tissue showed a dull blue luminescence. Additionally, when touched, it emitted a very strong blue light (Fig. 1c) that persisted for a few seconds. Coral tissue lit up strongest and flash like at the point of stimulation, and the illumination spread in a wave across the coenenchyme of the distal branches. The most intense light emission originated from the non-retractile sclerite-rich feeding polyps and remained visible for several minutes before it slowly faded. This phenomenon could be reproduced several times within hours. Luminescence in octocorals has been observed in the alcyonarian Anthomastus sp., as well as in isidid gorgonians (Isidella, Keratoisis, and Lepidisis), primnoid gorgonians (Primnoisis and Thouarella), and in Iridigorgia and Acanthogorgia (Herring 1987). Muzik (1978) documented bioluminescence in the isidid gorgonian Lepidisis olapa off Hawaii, and Etnoyer (2008) mentioned luminescent capabilities for Isidella tentaculum from the northeast Pacific. Just recently, bioluminescence was reported for Keratoisis flexibilis and for the zoanthid Gerardia sp. from the Gulf of Mexico (http://oceanexplorer.noaa.gov/explorations/09bioluminescence/). Likely due to the scarce availability of direct deep-sea sampling and observation, there are no further Atlantic records for bioluminescence in the Keratoisidinae outside the Gulf of Mexico. Our additional observations support that bioluminescence in Keratoisis and in other deep-sea gorgonians is rather common and deserves detailed in situ observations.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LP.biolum

Biomarker evidence for the origin of seep 1 oil and solid bitumen from the Late Devonian Siljan impact structure, Sweden - Ahmed, Manzur; Lehnert, Oliver; Fuentes, David; Meinhold, Guido (Organic Geochemistry, 2014)
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.LG.biomar

Biostratigraphic and chemostratigraphic correlation for the base of the Middle Ordovician between Yichang and Western Zhejiang areas, South China - Zhang, Yuandong; Munnecke, Axel; Cheng, Junfeng; Xiao, Liu; Chen, Xu (Acta Geologica Sinica - English Edition, 2011)
The base of the Middle Ordovician (i.e. Dapingian Stage) has been defined at the first appearance datum (FAD) of conodont Baltoniodus? triangularis at Huanghuachang, Yichang, China, but the precise correlation of the boundary to regions of other facies remain to be resolved. Herein we review the biostratigraphy and chemostratigraphy of the Huanghuachang Global Standard Stratotype-Section and Point (GSSP) section, and present our latest stratigraphic work on the nearby Chenjiahe section in Yichang, and the Hengtang Quarry section, Jiangshan, Zhejiang, which is regarded as representative of slope facies. The conodont and graptolite biostratigraphy as well as chemostratigraphy of the Chenjiahe section indicate that the base of the Middle Ordovician also falls within the graptolite Azygograptus suecicus Zone, and coincides with a high or maximum δ13C value within a minor positive carbon isotope excursion, suggesting that the base boundary can be readily recognized across the entire Yangtze Gorges area. The integrated graptolite and conodont biostratigraphy and chemostratigraphy of the Hengtang section, Jiangshan, indicates that the basal boundary probably falls within the graptolite Isograptus caduceus imitatus Zone that overlies the Azygograptus suecicus Zone, and coincides with a remarkable drop of δ13C. This difference indicates that a multi-disciplinary approach is critical to identify the base boundary in those regions where the Baltoniodus? triangularis is absent.
Keywords: Chemostratigraphy; Graptolite biostratigraphy; Middle ordovician; Slope facies; South china

Biostratigraphic precision of the Cruziana rugosa group: a study from the Ordovician succession of southern and central Bolivia. - Egenhoff, Sven; Weber, Bernd; Lehnert, Oliver; Maletz, Jörg (Geological Magazine, 2007)
Cruziana ichnospecies have been repeatedly reported to have biostratigraphic significance. This study presents a re-evaluation of the arthropod ichnotaxa of the Cruziana rugosa Group from bio- and/or lithostratigraphically well-defined Lower to Upper Ordovician siliciclastic sections of southern and central Bolivia. With the exception of Cruziana rouaulti, the ichnofaunas contain all the members of the Cruziana rugosa Group throughout the Ordovician (Arenig to Caradoc) successions in Bolivia. The Bolivian material therefore indicates that these arthropod ichnofossil assemblages are suitable for recognizing Ordovician strata in Bolivia. These findings cast doubt on their use as reliable indicators for a global intra-Ordovician (Arenig to Caradoc) biozonation of Peri-Gondwanan sedimentary successions. © 2007 Cambridge University Press.
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LG.biostr
Keywords: Biostratigraphy; Bolivia; Cruziana; Ordovician

Biostratigraphy and sequence stratigraphy of the Toarcian Ludwigskanal section (Franconian Alb, Southern Germany) - Arp, Gernot; Gropengießer, Sebastian; Schulbert, Christian; Jung, Dietmar; Reimer, Andreas (Zitteliana, 2021)
Extensive construction work at the canal cutting of the Ludwigskanal near Dörlbach, Franconian Alb, provided the opportunity to re-investigate a scientific-historical and biostratigraphically important reference section of the South-German Toarcian. The 16 m thick section, described bed by bed with respect to lithology and macrofossils, starts within the Upper Pliensbachian Amaltheenton Formation, covers the Toarcian Posidonienschiefer and Jurensismergel Formation, and ends in basal parts of the Opalinuston Formation. Carbonate contents are high in the Posidonienschiefer and successively decline within the Jurensismergel to basal parts of the Opalinuston. The high carbonate contents in the Posidonienschiefer are associated with comparatively low organic carbon contents. However, organic carbon contents normalized to the silicate fraction are similarily high if compared to other regions in Germany. Only the persistence of high organic carbon levels into middle parts of the Upper Toarcian differs from those of most regions in central Europe. Ammonite biostratigraphy indicates a thickness of >9 m for the Upper Pliensbachian, 1.15–1.20 m for the Lower Toarcian, 5.04 m for the Upper Toarcian, and >0.5 m for the Lower Aalenian. Despite the low sediment thickness, all Toarcian ammonite zones and almost all subzones are present, except for major parts of the Tenuicostatum Zone and the Fallaciosum Subzone. On the basis of discontinuities, condensed beds, and correlations with neighbouring sections in Southern Germany, a sequence stratigraphic interpretation is proposed for the Toarcian of this region: (i) The Posidonienschiefer Formation corresponds to one 3rd order T-R sequence, from the top of the Hawskerense Subzone to a fucoid bed at the top of the Variabilis Subzone, with a maximum flooding surface at the top of the Falciferum Zone. (ii) The Jurensismergel Formation exhibits two 3rd order T-R sequences: The first ranges from the basis of the Illustris Subzone (i.e., the Intra-Variabilis-Discontinuity) to the top of the Thouarsense Zone, with a maximum flooding surface within the Thouarsense Zone. The “belemnite battlefield” reflects a transgressive “ravinement surface” within the first Jurensismergel Sequence, not a maximum regression surface at its basis. The second sequence extents from the erosive basis of the Dispansum Zone to the top of the Aalensis Subzone, with a maximum flooding surface at the Pseudoradiosa-Aalensis Zone boundary. Finally, the Opalinuston starts with a new sequence at the basis of the Torulosum Subzone. Transgressive system tracts of these 3rd order T-R sequences are commonly phosphoritic, while some regressive system tracts show pyrite preservation of ammonites. The maximum regression surfaces at the basis of the Toarcian and within the Variabilis Zone reflect a significant submarine erosion and relief formation by seawater currents, while this effect is less pronounced at the basis of the Dispansum Zone and basis of the Torulosum Subzone (i.e., the boundary Jurensismergel-Opalinuston Formation
Keywords: Ammonoidea; Jurensismergel; Lower Jurassic; Posidonienschiefer; sealevel changes; Southern Germany; stratigraphy

Biostratygraficzne i geochemizne problemy identyfikacji granicy fran-famen w poludniowej Polsce. - Joachimski, Michael; et al. (Przeglad Geologiczny, 1999)
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LG.biostr

Biotemplating of BaFBr:Eu2+ for X-ray storage phosphor applications - Kostova, Marya H.; Batentschuk, Miroslaw; Götz-Neunhoeffer, Friedlinde; Gruber, Sabine; Winnacker, Albrecht; Greil, Peter; Zollfrank, Cordt (Materials Chemistry and Physics, 2010)
The design of hierarchically patterned novel structures by replicating the cellular tissue of wood has recently attained increasing interest. X-ray storage phosphor BaFBr:Eu2+ is manufactured via vacuum assisted repeated infiltration of wood tissue (Pinus sylvestris). A submicrometer precipitate is formed via wet chemical reaction of NH4F, BaBr2·2H2O and EuCl3·6H2O in methanol. According to scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), the original wood cell walls are filled with the precipitate and completely transformed into BaFBr struts after sintering at 800 °C. The optical properties of the biomorphous phosphor microstructure are determined by photoluminescence spectroscopy (PL) at room temperature, photo-stimulated luminescence spectroscopy (PSL) and cathodoluminescence spectroscopy (CL) in the SEM. A broadening of the PSL peak is observed and ascribed to the incorporation of calcium impurities present in the pine wood tissue. The potential of biotemplates for generating highly oriented and optically isolated μm- and sub-μm matrix of X-ray storage phosphor material is illustrated.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LM.biotem
Keywords: Optical properties; Biotemplating; X-ray storage phosphor

Biotic interactions in species distribution modelling: ten questions to guide interpretation and avoid false conclusions - Dormann, Carsten; Bobrowski, Maria; Dehling, Matthias; Harris, David; Hartig, Florian; Lischke, Heike; Moretti, Marco; Pagel, Jörn; Pinkert, Stefan; Schleuning, Matthias; Schmidt, Susanne; Sheppard, Christine; et al. (Global Ecology and Biogeography, 2018)
Aim: Recent studies increasingly use statistical methods to infer biotic interactions from co- occurrence information at a large spatial scale. However, disentangling biotic interactions from other factors that can affect co-occurrence patterns at the macroscale is a major challenge. Approach: We present a set of questions that analysts and reviewers should ask to avoid errone- ously attributing species association patterns to biotic interactions. Our questions relate to the appropriateness of data and models, the causality behind a correlative signal, and the problems associated with static data from dynamic systems. We summarize caveats reported by macroeco- logical studies of biotic interactions and examine whether conclusions on the presence of biotic interactions are supported by the modelling approaches used. Findings: Irrespective of the method used, studies that set out to test for biotic interactions find statistical associations in species’ co-occurrences. Yet, when compared with our list of questions, few purported interpretations of such associations as biotic interactions hold up to scrutiny. This does not dismiss the presence or importance of biotic interactions, but it highlights the risk of too lenient interpretation of the data. Combining model results with information from experiments and functional traits that are relevant for the biotic interaction of interest might strengthen conclusions. Main conclusions: Moving from species- to community-level models, including biotic interactions among species, is of great importance for process-based understanding and forecasting ecological responses. We hope that our questions will help to improve these models and facilitate the inter- pretation of their results. In essence, we conclude that ecologists have to recognize that a species association pattern in joint species distribution models will be driven not only by real biotic interac- tions, but also by shared habitat preferences, common migration history, phylogenetic history and shared response to missing environmental drivers, which specifically need to be discussed and, if possible, integrated into models.
Keywords: biotic interactions; communities; co-occurrence; environment; residual structure; species distribution models

Bivalve Mollusks as Hosts in the Fossil Record - Huntley, John Warren; de Baets, Kenneth; Scarponi, Daniele; Linehan, Liane Christine; Epa, Y. Ranjeev; Jacobs, Gabriel S.; Todd, Jonathan A. (The Evolution and Fossil Record of Parasitism: Coevolution and Paleoparasitological Techniques, 2021)
Parasites are ubiquitous in modern ecosystems, occupy one of the most successful life modes, promote ecosystem stability, and, despite their typically diminutive size and lack of a mineralized skeleton, are commonly identified in the fossil record. Bivalve mollusks have occupied marine aquatic environments since the Cambrian, comprise an excellent fossil record, and often preserve traces of interactions with their parasites. Here we review parasite-host interactions of living bivalves and the record of parasitism of bivalves that reaches as far back as the Silurian. Escalation in parasite-host bivalve interactions seems to have occurred in both the middle Paleozoic and the late Mesozoic to Cenozoic, similar to trends documented in other antagonistic interactions.
Keywords: Parasites; Pathogens; Paleoecology; Phanerozoic; Climate

Bivalves from the Finis Shale (Virgilian) of North Central Texas – analysis of life habits and palaeoecology - Friedel, Julia C.; Amler, Michael R.W.; Seuß, Barbara (Jahrestagung der Paläontologischen Gesellschaft, 2019)

Bivalves from the Pennsylvanian Finis Shale (Virgilian) of North Central Texas - Notes on taxonomy, life habits and palaeoecology - Friedel, Julia C.; Amler, Michael R.W.; Seuß, Barbara (GSA Annual Meeting, 2019)

Boiling effects on trace element and sulfur isotope compositions of sulfides in shallow-marine hydrothermal systems: Evidence from Milos Island, Greece - Schaarschmidt, Anna; Haase, Karsten; Klemd, Reiner; Keith, Manuel; Voudouris, Panagiotis C.; Alfieris, Dimitrios; Strauss, Harald; Wiedenbeck, Michael (Chemical Geology, 2021)
Boiling is a crucial process triggering ore formation in magmatic-hydrothermal systems and controlling the enrichment of precious and rare metal(loid)s in epithermal-porphyry mineralizations. Steep physicochemical gradients during boiling of hydrothermal fluids at shallow water depths caused metal(loid) precipitation along a 3 km long Pb-Zn-Ag vein system on Milos Island in the South Aegean Volcanic Arc. We present new trace element and Pb, Sr, and S isotope data from sulfides providing insights into the diversity of mineralization processes in shallow-marine hydrothermal systems. Lead and Sr isotope compositions of sulfides and sulfates reflect the mixing of fluids that reacted with metamorphic basement and the volcanic host rocks, whereas some of the S were derived from seawater. Investigation of mineralized samples along the Kondaros-Vani fault zone revealed distinct chemical variations that represent a vertical profile through the boiling zone of a hydrothermal system. Boiling during fluid ascent at decreasing temperatures (230–150 °C) and sulfur fugacities triggered the precipitation of sulfides rich in Zn, Pb, Fe, Cu, Ag, Sb, and As, resulting in increasing Pb, Ag, and Sb contents with decreasing depth. A pyrite group with high Tl/Cu and low As/Sb ratios, as well as δ34SVCDT values reaching as low as −6‰, is interpreted as precipitating from high-Cl liquids that underwent vigorous boiling at deeper crustal levels subsequent to tectonic faulting. Condensation of vapor (high Hg, Bi, and As contents) and mixing with seawater (high Mo contents) in the shallow-marine subseafloor sequences at Vani caused Hg-Bi-Mo-As-rich mineralization similar to the active hydrothermal system at Milos.
Keywords: Trace elements; Hydrothermal systems; Epithermal ore deposits; Boiling; Pyrite; Sulfur fugacity; Isotopes

Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system - Schmidt, Katja; Garbe-Schönberg, Dieter; Hannington, Mark; Anderson, Melissa; Bühring, Benjamin; Haase, Karsten; Haruel, Christy; Lupton, John; Koschinsky, Andrea (Geochimica Et Cosmochimica Acta, 2017)
In 2013, high-temperature vent fluids were sampled in the Nifonea vent field. This field is located within the caldera of a large shield-type volcano of the Vate Trough, a young extensional rift in the New Hebrides back-arc. Hydrothermal venting occurs as clear and black smoker fluids with temperatures up to 368 °C, the hottest temperatures measured so far in the western Pacific. The physico-chemical conditions place the fluids within the two-phase field of NaCl–HO, and venting is dominated by vapour phase fluids with Cl concentrations as low as 25 mM. The fluid composition, which differs between the individual vent sites, is interpreted to reflect the specific geochemical fluid signature of a hydrothermal system in its initial, post-eruptive stage. The strong Cl depletion is accompanied by low alkali/Cl ratios compared to more evolved hydrothermal systems, and very high Fe/Cl ratios. The concentrations of REY (180 nM) and As (21 μM) in the most Cl-depleted fluid are among the highest reported so far for submarine hydrothermal fluids, whereas the inter-element REY fractionation is only minor. The fluid signature, which has been described here for the first time in a back-arc setting, is controlled by fast fluid passage through basaltic volcanic rocks, with extremely high water-rock ratios and only limited water-rock exchange, phase separation and segregation, and (at least) two-component fluid mixing. Metals and metalloids are unexpectedly mobile in the vapour phase fluids, and the strong enrichments of Fe, REY, and As highlight the metal transport capacity of low-salinity, low-density vapours at the specific physico-chemical conditions at Nifonea. One possible scenario is that the fluids boiled before the separated vapour phase continued to react with fresh glassy lavas. The mobilization of metals is likely to occur by leaching from fresh glass and grain boundaries and is supported by the high water/rock ratios. The enrichment of B and As is further controlled by their high volatility, whereas the strong enrichment of REY is also a consequence of the elevated concentrations in the host rocks. However, a direct contribution of metals such as As from magmatic degassing cannot be ruled out. The different fluid end-member composition of individual vent sites could be explained by mixing of vapour phase fluids with another fluid phase of different water/rock interaction history.
Keywords: Early-stage; Hydrothermal fluids; Nifonea; Phase separation; Rare earth elements

Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system - Schmidt, Katja; Garbe-Schönberg, Dieter; Hannington, Mark; Anderson, Melissa; Bühring, Benjamin; Haase, Karsten; Haruel, Christy; Lupton, John; Koschinsky, Andrea (Geochimica Et Cosmochimica Acta, 2017)
Keywords: Early-stage; Phase separation; Rare earth elements; Hydrothermal fluids; Nifonea

Borehole measurements in geothermal wells: Why one should measure and know certain parameters - Bauer, Wolfgang (EAGE/BVG/FKPE Joint Workshop on Borehole Geophysics and Geothermal Energy, 2019)
Geothermal projects are often characterized by high cost pressure and a focused on the implementation of a single project. As a result, a comprehensive borehole measurement program is often dispensed with and only a minimum of measurements are performed. The purpose of this talk is to clarify the importance of borehole measurements with regard to a comprehensive understanding of the subsurface and to explain the necessity of certain measurement methods by means of a proposal for a measurement program.
CRIS-Team Scopus Importer:2021-04-20

Boron isotope geochemistry of Paleozoic brachiopod calcite: Implications for a secular change in the boron isotope geochemistry of seawater over the Phanerozoic - Joachimski, Michael; van Geldern, Robert; et al. (Geochimica Et Cosmochimica Acta, 2005)
Boron isotope composition of marine carbonates has been proposed as a paleo-pH proxy and potential tool to reconstruct atmospheric pCO. The precise knowledge of the boron isotopic composition of ancient seawater represents the fundamental prerequisite for any paleo-pH reconstruction. This contribution presents boron isotope values for Silurian to Permian brachiopod calcite that might be used to reconstruct pH or boron isotope composition of past oceans. All brachiopod shells were screened for diagenetic recrystallization by means of cathodoluminescence microscopy, trace element geochemistry (B, Fe, Mn, Sr) as well as SEM. Only nonluminescent shells revealing well-preserved microstructures, high strontium and boron concentrations as well as low iron and manganese contents were accepted for boron isotope analysis. The boron isotope ratios of Silurian, Devonian, Pennsylvanian and Permian brachiopod calcite range from 6.8 to 11.0‰, 7.3 to 14.9‰, 12.4 to 15.8‰ and 10.1 to 11.7‰, respectively. These δB values are significantly lower in comparison to δB values of modern biogenic carbonates and indicate that the Paleozoic oceans were depleted in B by up to 10‰. Box modeling of the boron geochemical cycle suggests that the significant depletion of B in the oceanic reservoir may have been initiated by an enhanced continental boron discharge. Our data support the earlier made conclusion that boron isotopes may not be used in the geological past as reliable paleo-pH proxy unless the boron isotopic composition of ancient oceans can be constrained by further studies. Copyright © 2005 Elsevier Ltd.

Brackish water algal reefs – facies analysis as a tool to identify palaeoenvironmental variations in Miocene deposits (Mainz-Weisenau, Germany) - Nohl, Theresa; Knoblach, Julia; Teichert, Sebastian (Geological Journal, 2021)
Brackish-water carbonates are far less studied than their marine or limnic counterparts. However, their association with few, specialized species enables the documentation of fine-scale changes in the depositional environment. The Cenozoic Mainz Basin (Germany) was only sporadically connected to the North Sea and the Paratethys, exposing several transitions from marine to fresh water influence. Focusing on one outcrop of the Rüssingen Formation of Mainz-Weisenau (Aquitanian, Miocene), we present a detailed analysis of the faunal and sedimentological responses to changing salinities and water depth, including algal reef growth and facies development. The deposits include allochthonous limestones surrounding an autochthonous reef complex and several smaller reef patches. The allochthonous facies is dominated by the gastropod Hydrobia inflata, and the reef facies is mainly made up by the green alga Cladophorites sp. The algal thalli are overgrown by cryptocrystalline, organic precipitations, and laminated, chemical precipitations. Locally, quiver-shaped structures of Trichoptera sp. protective cases occur. The depositional setting was a shallow, low energy, and brackish environment supersaturated by carbonate. We could not confirm a general trend of reducing salinities as reported for the Rüssingen Formation. Our results question previously reported episodic desiccation events, because apparent caliche horizons actually represent thin beds of increased Cladophorites growth. Set-up, distribution of the reef facies, and reef debris indicate short-time variations of temperature, salinity and water depth. We conclude that these variations are based on the geographic position at the edge of an algal reef barrier, separating the Mainz Basin from the Rhine Rift Valley.<br
Keywords: algal reefs; brackish deposits; Cladophorites sp.; facies development; microbial calcite precipitation

Brittle reactivation of ductile shear zones in NW Namibia in relation to South Atlantic rifting - Salomon, Eric; Koehn, Daniel; Passchier, Cees (Tectonics, 2015)
Rifting has occurred worldwide along preexisting mobile belts, which are therefore thought to control rift orientation on a large scale. On a smaller scale, shear zones within mobile belts are reactivated as rift faults. In NW Namibia, shear zones of the Neoproterozoic Kaoko Belt run subparallel to the present-day continental passive margin and are inferred to have been reactivated during the opening of the South Atlantic Ocean. However, the extent of this reactivation and the influence of the reactivated shear zones on South Atlantic rifting are largely unknown. A combined remote sensing and field study was conducted to quantify offsets that are a direct function of shear zone reactivation. The shear zones of the Kaoko Belt are partly overlain by the Parana-Etendeka volcanic rocks, which were emplaced shortly before or simultaneously to the Atlantic rifting. Faulting within these volcanic rocks can be linked to synrift or postrift movements. Along the shear zones, downfaulting of the basalts is widespread along listric faults where half-graben form in the hanging wall. At three sites we could determine vertical offsets of similar to 1180m, similar to 470m, and similar to 70m. Although many shear zones were reactivated as faults, these are isolated, and offsets are small, suggesting that reactivation occurred only as a side effect of the rifting and that the Kaoko Belt shear zones have not exerted a significant influence on the rift orientation.
Keywords: Kaoko Belt; Neoproterozoic; Pan-African orogeny; rift border fault; fault displacement; rift geometry

Bryozoan fauna of the Boggy Formation (Deese Group, Pennsylvanian) of the Buckhorn Asphalt Quarry, Oklahoma, USA - Ernst, Andrej; Seuß, Barbara; Taylor, Paul; Nützel, Alexander (Palaeobiodiversity and Palaeoenvironments, 2016)

Bryozoan-rich stromatolites (bryostromatolites) from the Silurian of Gotland and their relation to climate-related perturbations of the global carbon cycle - Claußen, Anna Lene; Munnecke, Axel; Ernst, Andrej (Sedimentology, 2021)
Bryozoan–stromatolite associations (bryostromatolites) formed conspicuous reef structures throughout the Sheinwoodian (Wenlock) to Ludfordian (Ludlow) stratigraphy on Gotland but have not been described so far. They are mainly composed of encrusting bryozoans forming a complex intergrowth with porostromate and spongiostromate microbes and are different from the abundant stromatoporoid–coral–algal reefs with respect to their composition. In the bryostromatolite different growth stages can be identified. The observed succession can be taken as evidence for cyclic environmental changes during reef formation. Stenohaline reef-dwelling organisms, such as echinoderms, sponges, corals and trilobites, indicate fully marine salinities. Ten localities exposing bryostromatolites were discovered. Individual bryostromatolites are small with few decimetres up to one metre in size, and occur solely in shallow marine areas. Common features of these reefs on Gotland are cauliflower-like growth, a high bryozoan diversity, a high abundance of phosphatic fossils and components such as bryozoan pearls and inarticulate phosphatic brachiopods, enhanced bioerosion, Palaeomicrocodium crusts, vadose silt and gypsum pseudomorphs. The high abundance of Palaeomicrocodium, as well as the alternation with other crust-forming contributors, suggest that it could have been formed directly at the palaeo-sea surface, probably in times of minor but high-frequency sea-level fluctuations. Vadose silt and pseudomorphs after gypsum in reef cavities indicate subaerial exposure shortly after reef growth. The high amount of phosphatic components indicates a high nutrient input, probably by dust. All bryostromatolites were formed in times of strongly elevated δ13C values. The unusual combination of sedimentological and palaeoecological features, as well as their occurrence exclusively during strong positive δ13C excursions, are evidence that the bryostromatolite development responded to climatic/oceanographic changes, which may have played an important role in reef control.
CRIS-Team Scopus Importer:2021-05-21
Keywords: Palaeomicrocodium; phosphate; reef; stable carbon isotopes; subaerial exposure

Bryozoans from the lower Silurian (Telychian) Hanchiatien Formation from southern Chongqing, South China - Ernst, Andrej; Li, Qi Jian; Zhang, Min; Munnecke, Axel (Journal of Paleontology, 2021)
Eight bryozoan species are described from the Hanchiatien Formation (lower Silurian, Telychian) of southern Chongqing, South China. Four species are new: the trepostomes Asperopora sinensis n. sp., Trematopora jiebeiensis n. sp., and Trematopora tenuis n. sp., and the fenestrate Moorephylloporina parvula n. sp. One species, the cystoporate Hennigopora sp. indet., is described in open nomenclature. Moorephylloporina parvula n. sp. is eurytopic, occurring in all types of facies within the bioherms. Erect Moorephylloporina Bassler, 1952, Trematopora Hall, 1852, and Leioclema Ulrich, 1882 formed pioneering communities on weakly cemented substrata, whereas encrusting Fistulipora M'Coy, 1849, Hennigopora Bassler, 1952, and Asperopora Owen, 1969 occurred on hardgrounds and formed densely compact framestones. Robust branched Trematopora and Leioclema tend to occur out of the reef core (framework) where they could have formed reef-flank thickets in more agitated conditions. The generic composition of the studied fauna correlates with other localities in South China, and they show general paleobiogeographic relations to Siberia and Indiana, USA. UUID http://zoobank.org/3326dd2f-7c9e-43bc-9dab-84047b274f89
CRIS-Team Scopus Importer:2021-03-26

Buckman’s Rules of Covariation - de Baets, Kenneth; Monnet, Claude; Yacobucci, Margaret M. (Ammonoid Paleobiology: From macroevolution to paleogeography, 2015)

Bulk density and water content-dependent electrical resistivity analyses of different soil classes on a laboratory scale - Bertermann, David; Schwarz, Hans (Environmental Earth Sciences, 2018)
The goal of this study was to achieve relations between electrical conductivity and the most influential soil properties which should be transferable to natural field conditions. Electrical conductivity of soil is mainly affected by soil moisture. This, for many soil applications like determination of thermal soil properties, crucial relation is focused within this article. Electrical conductivity was measured in dependency of bulk density and water content by applying a laboratory setup which enables a comparison to natural in-situ conditions. For this purpose, four different pressure loads and up to 12 saturation steps were performed on the textural soil types of sand, silt loam and clay. A comparison between electrical conductivity and saturated pore volume confirms the impact of soil moisture. For the final analysis natural conditions were specified using field capacity ranges and defined bulk densities. With these predetermined ranges of water content and bulk density a healthy regulation for defining natural conditions has been constructed. Due to this generated constraint a soil texture independent relation between electrical conductivity and soil moisture content with a correlation coefficient of r2 = 0.95 has been developed. This correlation was also implemented within the developed measurement tool of the GeoSurf project for determining the thermal potential of soil.
Created from Fastlane, Scopus look-up
Keywords: Bulk density; Electrical conductivity; Field capacity; Laboratory setup; Water saturation

Buoyancy mechanisms limit preservation of coleoid cephalopod soft tissues in Mesozoic Lagerstätten - Clements, Thomas; Colleary, Caitlin; de Baets, Kenneth; Vinther, Jakob (Palaeontology, 2017)
Coleoid cephalopods are characterized by internalization of their shell, and are divided into the ten-armed Decabrachia (squids and cuttlefish) and the eight-armed Vampyropoda (octopuses and vampire squid). They have a rich fossil record predominantly of the limited biomineralized skeletal elements they possess: arm hooks, statoliths, mouthparts (the buccal mass) and internal shell (gladius or pen), although exquisitely preserved soft tissue coleoids are known from several Lagerstatten worldwide. Recent studies have shown that although morphological similarities between extant decabra-chian gladii and fossil examples exist, no known examples of fossil decabrachians are currently known. However, molecular clock data and phylogenetic bracketing suggest that they should be present in Lagerstatten that are rich in vampyropod soft tissue fossils (i.e. Hakel and Hadjoula Lagerstatten, Cretaceous, Lebanon). We propose that a hitherto unknown taphonomic bias pertaining to the differing methods of buoyancy control within coleoid groups limits preservation potential. Both negatively and neutrally buoyant decabrachians use chemical buoyancy control (ammonia) whereas vampyropods do not. In the event of rapid burial in an environment conducive to exceptional preservation, ammonia dramatically decreases the ability of the decabrachian carcass to generate the required pH for authigenic calcium phosphate replacement, limiting its preservation potential. Moreover, the greater surface area and comparatively fragile dermis further decrease the potential for fossilization. This taphonomic bias may have contributed to the lack of preserved labile soft-tissues in other cephalopods groups such as the ammonoids.
Keywords: coleoid; cephalopod; buoyancy; calcium phosphate; taphonomy; bias

Burned and devoured-Introduced herbivores, fire, and the endemic flora of the high-elevation ecosystem on La Palma, Canary Islands - Irl, Severin; Steinbauer, Manuel; Messinger, Jana; Blume-Werry, Gesche; Palomares Martínez, Angel; Beierkuhnlein, Carl; Jentsch, Anke (Arctic, Antarctic, and Alpine Research, 2014)
Novel disturbance regimes (e.g., introduced herbivores and fire) are among the major drivers of degradation in island ecosystems. High-elevation ecosystems (HEEs) on islands might be especially vulnerable to these disturbances due to high endemism. Here, data from an 11-year exclosure experiment in the HEE of La Palma (Canary Islands) are presented where mammalian herbivores have been introduced. We investigate the combined effect of herbivory and fire on total species richness, seedling richness, and seedling establishment on the whole system and a subset of highly endangered species (target species). Total species richness, seedling species richness, and seedling establishment decreased with herbivory. Five out of eight target species were exclusively found inside the exclosures indicating the negative impact of introduced herbivores on endemic high elevation flora. Target species were generally affected more negatively by introduced herbivores and were subject to significantly higher browsing pressure, probably owing to their lack of defense strategies. A natural wildfire that occurred six years before data sampling substantially increased total species richness and seedling richness in both herbivory exclosure and reference conditions. We conclude that species composition of the HEE has been severely altered by the introduction of non-native herbivores, even though fire seems to have a positive effect on this system.

Calcareous algae from the Triassic (Anisian reef boulders and Norian reef limestones) of Karaburun, western Turkey - Senowbari-Daryan, Baba; Link, Michael; Isintek, Ismail (Facies, 2006)
Invertebrate Anisian and Norian reef boulders were found in the Gerence and Güvercinlik Formations, respectively, exposed in northeastern part of the Karaburun Peninsula, western Turkey. Halimedacean green algae and solenoporacean red algae, usually associated with other reef building organisms are described in this paper. The following taxa were determinated: halimedaceans: Egericodium hungaricum Flügel, Velledits, Senowbari-Daryan and Riedel, Aternasus irregularis n. gen., n. sp.; solenoporaceans: Solenopora cf. alcicornis Ott, Solenopora triasina Vinassa de Regny, Solenopora vachardi n. sp., Solenopora concentrica n. sp., Solenopora paraconcentrica n. sp., Tauristorea parallela Senowbari-Daryan and Link, Tauristorea discursa n. sp., and Parachaetetes cassianus (Flügel). The monospecific genus Aternasus n. gen. is the most abundant alga within the Anisian reef boulders. The solenoporaceans are represented by several taxa but the individual species are less abundant. E. hungaricum, T. parallela Senowbari-Daryan and Link, and S. triasina Vinassa de Regny are described from the Norian reef limestones embedded in Güvercinlik Formation, all other taxa from the Anisian reef boulders embedded in the Gerence Formation. © Springer-Verlag 2005.
UnivIS-Import:2015-04-14:Pub.2006.nat.dgeo.IGM.LP.calcar
Keywords: Algae; Anisian; Karaburun; Norian; Triassic; Turkey

Calcareous, alluvial and lacustrine deposits in the Old Red Sandstone of central north Spitsbergen (Wood Bay Formation, Early Devonian) - Joachimski, Michael; et al. (Norwegian Journal of Geology, 2003)
Within the silidelastic dominated red-bed strata of the Early Devonian Wood Bay Formation, various types of calcareous deposits, characterised by specific sedimentary structures, lithologies, microfacies, carbonate contents and stable isotope signatures, occur at different stratigraphie levels. Pedogenic, nodular calcretes with a thickness from 40 to 150 centimetres, associated with alluvial-plain and overbank sediments, represent palaeosol (calcisols, aridisols) development. The massive nodules show an internal mudstone fabric, calcium carbonate concentrations from 64 to 87 % and carbon and oxygen signatures of-5.3 to -6.4 and -8.5 to -9.9 ‰, respectively. It is likely that they reflect a bio-induced carbonate precipitation in an oxygenated near-surface setting, connected with the evaporation of ground water. Single, up to some decimetres thick beds of calcareous mudstones and marls are characterised by a gradual colour change from reddish-brown to grey-violet upwards, and a meshwork of desiccation cracks at the top. The sediments show calcium carbonate concentrations from 22 to 43 % and carbon and oxygen isotope values ranging from -0.6 to -0.7 ‰ and -7.6 to -8.8 ‰, respectively. They are interpreted as deposits of relatively small, ephemeral lakes, formed by inorganic carbonate precipitation due to the evaporation of surface water. Individual beds and regressive, shallowing-upward sequences, up to a few metres thick, formed of calcareous mudstones to sandstones, marls to calcarenites and argillaceous to sandy limestones represent the depositional products of perennial, low-relief, low-energy lakes, These sediments yield carbonate concentrations from 20 to 81 % and a stable isotope composition of-2.1 to -3.1 %o for δC and -9.5 to -10.9 ‰ for δO. They reflect deposition in basinal and littoral lacustrine and palustrine sub-environments, in which carbonate was formed due to inorganic, bio-induced and biotic precipitation. The different types of calcareous deposits formed under arid to semi-arid climatic conditions in various sub-environments of alluvial plains and perennial lakes. Their occurrence at different stratigraphie levels within the Wood Bay Formation can be related to a gradually increasing geomorphologic maturity of the terrestrial basin. The latter was marked by a decrease of the topographic relief and a lowering of sedimentation rates. An increase in landscape stability, combined with a general water-level rise led to the recurrent formation of broad lake plains in the centre of the basin.

"Calcispheres" as a source of lime mud and peloids evidence from the early Middle Devonian of the Prague Basin, the Czech Republic - Berkyová, Stanislava; Munnecke, Axel (Bulletin of Geosciences, 2010)
Several types of peloids are present in the Lower and Middle Devonian limestones of the Prague Basin (uppermost part of the Třebotov Limestone of the Daleje-Třebotov Formation and Choteč Formation, uppermost Emsian-Eifelian) and are interpreted as being of calcispheral, echinoderm, and/or calcimicrobial origin. Possible mechanisms of peloid formation, the mode of life of calcispheres and their role in the accumulation of Paleozoic lime mud are discussed. Mass occurrences of peloids and calcispheres are characteristic features of the Choteč Formation (Eifelian, costatus-kockelianus conodont zones). It is concluded that specific environmental conditions, such as a higher nutrient load, existed during the sedimentation of this unit, probably in response to the Basal Choteč event.
Keywords: Calcispheres; Devonian; Lime mud; Micritization; Peloids; Prague basin

Calciumferrathydrate - Speicherminerale zur Immobilisierung von Halogeniden in industriellen Prozessrückständen - Götz-Neunhoeffer, Friedlinde; Pöllmann, Herbert (1992)
UnivIS-Import:2015-03-05:Pub.1992.nat.dgeo.IGM.LM.calciu

Calcium isotope record of Phanerozoic oceans: Implications for chemical evolution of seawater and its causative mechanisms - Farkaš, Juraj; Eisenhauer, Anton; van Geldern, Robert; Munnecke, Axel; et al. (Geochimica Et Cosmochimica Acta, 2007)
A total of 280 brachiopods of Ordovician to Cretaceous age, complemented by published data from belemnites and planktonic foraminifera, are used to reconstruct the evolution of calcium isotope composition of seawater (δCa) over the Phanerozoic. The compiled δCa record shows a general increase from ∼1.3‰ (NIST SRM 915a) at the beginning of the Ordovician to ∼2‰ at present. Superimposed on this trend is a major long-term positive excursion from the Early Carboniferous to Early Permian as well as several short-term, mostly negative, oscillations. A numerical model of the global cycles of calcium, carbon, magnesium and strontium was used to estimate whether the recorded δCa variations can be explained by varying magnitudes of input and output fluxes of calcium to the oceans. The model uses the record of marine Sr/Sr ratios as proxy for seafloor spreading rates, a record of oceanic Mg/Ca ratios to estimate rates of dolomite formation, and reconstructed atmospheric CO, discharge and erosion rates to estimate continental weathering fluxes. The model results indicate that varying magnitudes of the calcium input and output fluxes cannot explain the observed δCa trends, suggesting that the isotope signatures of these fluxes must also have changed. As a possible mechanism we suggest variable isotope fractionation in the sedimentary output flux controlled by the dominant mineralogy in marine carbonate deposits, i.e. the oscillating 'calcite-aragonite seas'. The ultimate control of the calcium isotope budget of the Phanerozoic oceans appears to have been tectonic processes, specifically variable rates of oceanic crust production that modulated the hydrothermal calcium flux and the oceanic Mg/Ca ratio, which in turn controlled the dominant mineralogy of marine carbonates, hence the δCa. As to the causes of the short-term oscillations recorded in the secular δCa trend, we tentatively propose that these are related to variable rates of dolomite formation and/or to changing chemical composition of the riverine flux, in particular Ca / HCO and Ca / SO ratios, induced by variable proportions of silicate vs. carbonate weathering rates on the continents. © 2007 Elsevier Ltd. All rights reserve

Calculating energy and its spatial distribution for a subsurface urban heat island using a GIS-approach - Schweighofer, Julian; Wehrl, Michael; Baumgärtel, Sebastian; Rohn, Joachim (Geosciences, 2021)
In urban areas, the human influence on the city-ecosystem often results in a Subsurface Urban Heat Island (SUHI), which can be used geothermally. Unfortunately, a model of a SUHI does not consider the geology and hydrogeology of the subsoil. These can vary significantly over short distances, and are of considerable importance for the energy balance. In this work, we calculated the energy and its density stored in the subsoil via a SUHI. For this so-called energy-SUHI (e-SUHI), we evaluated the geology and its physical parameters for the first 20 m below ground level in the German city of Nuremberg and linked them to measured underground temperatures in a GIS application. This approach revealed stored energy of 1.634 × 1010 MJ within the soil and water for the study area with an area of 163 km2 and a volume of 3.26 × 109 m3. It corresponds to an average energy density of 5.0 MJ/m3. The highest energy density of 16.5 MJ/m3 was found in the city center area and correlated well to increases in subsurface temperature. As expected, our model reacts sensitively to thickness changes in the geological layers and the unsaturated zone.
CRIS-Team Scopus Importer:2021-01-29
Keywords: Energy-SUHI; Geothermal energy; GIS; Subsurface Urban Heat Island (SUHI)

Calibration and quantitative analysis of C2AHx (2CaO·Al2O3·xH2O) by Rietveld refinement combined G-factor method - Goergens, Julian; Köhler, Andreas; Götz-Neunhoeffer, Friedlinde (Cement and Concrete Research, 2022)
This work presents a novel way to use X-ray diffraction (XRD) to quantify the plate-like calcium-aluminate-hydrate phases C2AHx (2CaO·Al2O3·xH2O), for which three different basal spacings are detected during early hydration at ambient temperatures. By combining Rietveld refinement and the G-factor method, C2AH7.5 was calibrated using a variety of syntheses and preparations for XRD. Since cell volume and X-ray density (that are necessary for the G-factor method) of C2AH7.5 are not known, an approach similar to [1,2] was used for the generation of a hkl-phase model: A “F-factor” – a factor that replaces the product of these two unknowns, which was verified by the multitude of syntheses – was successfully determined within this paper. The model was applied for the absolute quantification of C2AHx during in-situ XRD of CA (CaO·Al2O3) hydration at 40 °C. The results demonstrate the potential of the hkl-phase model in practical use and reveal the accuracy of the determined F-factor.
CRIS-Team Scopus Importer:2022-06-10
Keywords: Calcium aluminate cement (D); Crystal structure (B); Hydration (A); Hydration products (B); X-ray diffraction (B)

Calorimetry investigations of milled alpha-tricalcium phosphate (alpha-TCP) powders to determine the formation enthalpies of alpha-TCP and X-ray amorphous tricalcium phosphate - Hurle, Katrin; Neubauer, Jürgen; Bohner, Marc; Doebelin, Nicola; Götz-Neunhoeffer, Friedlinde; Götz-Neunhoeffer, Friedlinde (Acta Biomaterialia, 2015)
One alpha-tricalcium phosphate (alpha-TCP) powder was either calcined at 500 degrees C to obtain fully crystalline alpha-TCP or milled for different durations to obtain alpha-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71 wt.% ATCP and up to 2.0 +/- 0.1 wt.% beta-TCP as minor phase were then hydrated in 0.1 M Na2HPO4 aqueous solution and the resulting heat flows were measured by isothermal calorimetry. Additionally, the evolution of the phase composition during hydration was determined by in situ XRD combined with the G-factor method, an external standard method which facilitates the indirect quantification of amorphous phases. Maximum ATCP hydration was reached after about 1 h, while that of crystalline alpha-TCP hydration occurred between 4 and 11 h, depending on the ATCP content. An enthalpy of formation of -4065 6 kJ/mol (T = 23 degrees C) was calculated for ATCP (Ca-3(PO4)(2)), while for crystalline alpha-TCP (alpha-Ca-3(PO4)(2)) a value of -4113 +/- 6 kJ/mol (T= 23 degrees C) was determined. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-07-08:Pub.2015.nat.dgeo.IGM.LM.calori
Keywords: Calcium phosphate cement; CDHA; Amorphization; Heat flow calculation; Isothermal calorimetry

Cambrian to Lower Ordovician reefs on the Yangtze Platform, South China Block, and their controlling factors - Zhang, Yuanyuan; Li, Qijian; Li, Yue; Kießling, Wolfgang; Wang, Jianpo (Facies, 2016)
The Yangtze Platform, South China Block, maintained an epicontinental sea in the Cambrian and Ordovician with oldlands surrounding its northern and western margins and a southeastern slope belt. Many Cambrian to Lower Ordovician reef complexes are known from the Yangtze Platform for which an updated spatiotemporal framework is provided, their biotic composition and architecture is presented, and the reef development is discussed in a global context. The biotic structures of reef units on the Yangtze Platform largely match the evolutionary pattern in terms of composition and architecture. Microbes and calcareous algae are key components in all reefs but metazoan reef-builders are better suited to identifying macroevolutionary patterns. Large-scale dolomitization in Cambrian Series 4 on the one hand prevents recognition of metazoan reefs and on the other hand may indicate hypersaline environments, which prevented metazoan reef growth and only permitted small-scale stromatolites in a few regions. Ordovician metazoans appear to have played substantial roles in reef-building earlier on the Yangtze Platform than elsewhere. Specifically bryozoan and Calathium-lithistid sponge reefs diversified during the Early Ordovician. Climate and eustatic sea-level changes and their related impact on water energy, turbidity, and salinity determined the growth and demise of reefs. The morphology and arrangement of reefs were controlled by the topography of the sea floor.
UnivIS-Import:2016-06-01:Pub.2016.nat.dgeo.IGM.LP.cambri
Keywords: Cambrian; Early Ordovician; Paleogeography; Reefs; South China Block; Yangtze Platform

Cambro-Ordovician sea level fluctuations and sequence boundaries: the missing record and the evolution of new taxa - Lehnert, Oliver; Miller, James F.; Leslie, Stephen A.; Repetski, John E.; Ethington, Raymond L. (Special Papers in Palaeontology Series, 2005)
The evolution of early Palaeozoic conodont faunas shows a clear connection to sea-level changes. One way that this connection manifests itself is that thick successions of carbonates are missing beneath major sequence boundaries due to karstification and erosion. From this observation arises the question of how many taxa have been lost from different conodont lineages in these incomplete successions. Although many taxa suffered extinction due to the environmental stresses associated with falling sea-levels, some must have survived in these extreme conditions. The number of taxa missing in the early Palaeozoic tropics always will be unclear, but it will be even more difficult to evaluate the missing record in detrital successions of higher latitudes. A common pattern in the evolution of Cambrian-Ordovician conodont lineages is appearances of new species at sea-level rises and disappearances at sea-level drops. This simple picture can be complicated by intervals that consistently have no representatives of a particular lineage, even after extensive sampling of the most complete sections. Presumably the lineages survived in undocumented refugia. In this paper, we give examples of evolution in Cambrian-Ordovician shallowmarine conodont faunas and highlight problems of undiscovered or truly missing segments of lineages. © The Palaeontological Association.
UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LG.cambro
Keywords: Cambrian; Conodont record; Evolution; Ordovician; Sea-level changes; Sequence stratigraphy

Cambro-Ordovician sponge spicule assemblages in the Ordovician of the Argentine Precordillera and paleoenvironmental ties - Jaanussen, Dorte; Lehnert, Oliver (Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 1997)

Cameral deposits in a sublethally damaged Pennsylvanian “Michelinoceras sp.” from the Buckhorn Asphalt Lagerstätte in Oklahoma, USA - Seuß, Barbara; Mapes, Royal H.; Klug, Christian; Nützel, Alexander (Annual Meeting of the Palaeontological Association, 2010)
The recovery of two well-preserved chambers of the phragmocone of Pseudorthoceras sp. from the Buckhorn Asphalt Lagerstätte provides nw insight into the controversy over how cameral deposits are developed in orthoconic nautiloids. The specimen has two oval openings in the conch, a result of penetrating the outer test and present cameral deposits. The animan survived the attack and was able to still precipitate cameral deposits, astonishing because in the orad chamber the bite-marks opened the chamber to the seawater. Three hypotheses of cameral deposit precipitation can be tested: (1) direct precipitation from the cameral fluid; (2) precipitation from the cameral fluid with a reoccurring organic template/membrane; (3) secretion by a cameral tissue. (1) and (2) cannot be supported because the precipitation chemistry of the cameral fluid is altered and cannot be controlled by the animal. (3) remains possible: the penetration marks would be sealed by cameral tissue regeneration and cameral deposits would be precipitated directly by such tissue. Thus, the cameral fluid chemistry would appear not to be important for cameral deposit precipitation. Anyhow, this hypothesis remains problematic: there are no known openings that would allow tissure connections from the siphuncle through the connecting ring to the cameral deposit

Cameral deposits in a sublethally damaged Pennsylvanian Pseudorthoceras sp. from the Buckhorn Asphalt Lagerstätte in Oklahoma, USA - Seuß, Barbara; Mapes, Royal H.; Klug, Christian; et al. (Annual Meeting of the Paläontologische Gesellschaft, 2010)
The recovery of two well-preserved chambers of the phragmocone of Pseudorthoceras sp. from the Buckhorn Asphalt Lagerstätte provides nw insight into the controversy over how cameral deposits are developed in orthoconic nautiloids. The specimen has two oval openings in the conch, a result of penetrating the outer test and present cameral deposits. The animan survived the attack and was able to still precipitate cameral deposits, astonishing because in the orad chamber the bite-marks opened the chamber to the seawater. Three hypotheses of cameral deposit precipitation can be tested: (1) direct precipitation from the cameral fluid; (2) precipitation from the cameral fluid with a reoccurring organic template/membrane; (3) secretion by a cameral tissue. (1) and (2) cannot be supported because the precipitation chemistry of the cameral fluid is altered and cannot be controlled by the animal. (3) remains possible: the penetration marks would be sealed by cameral tissue regeneration and cameral deposits would be precipitated directly by such tissue. Thus, the cameral fluid chemistry would appear not to be important for cameral deposit precipitation. Anyhow, this hypothesis remains problematic: there are no known openings that would allow tissure connections from the siphuncle through the connecting ring to the cameral deposit

Can Conductivity and Stable Isotope Tracers determine Water Sources during Flooding? An example from the Elbe River in 2002 - Barth, Johannes; et al. (International Journal of River Basin Management, 2006)

Carbon and conodont apatite oxygen isotope records from the Alengchu section in western Yunnan and their paleoclimatic and paleogeographic implications - Chen, Bo; Zhang, Mei Qiong; Qie, Wen Kun; Liang, Kun; Lu, Jian Feng; Joachimski, Michael; Ma, Xue Ping (Palaeoworld, 2023)
The Early Devonian witnessed dramatic changes in climate, ocean chemistry and faunal evolution. However, previous studies have relied mainly on records from North America and Europe (Prague Basin, Carnic Alps) and Australia, while data from China have been rarely reported, hindering robust δ13Ccarb chemostratigraphic correlation and evidence for the global significance of these events. Here, we report new carbon isotope and conodont apatite oxygen isotope records from the Alengchu section in western Yunnan which represents the most continuous Lower Devonian carbonate succession in China. Our study reports two positive δ13Ccarb excursions (Klonk isotope event, Lochkovian–Pragian isotope event) that can be correlated with published records globally. However, δ18Oapatite values are higher compared to coeval data from other sections. These higher values are interpreted as indicating cooler surface water temperatures as consequence of a persistent upwelling system at low latitudes which is consistent with the paleooceanographic circulation pattern reconstructed from combined evidence of climate modelling and geographic distribution of marine benthic ostracod assemblages.
CRIS-Team Scopus Importer:2023-02-03
Keywords: Klonk isotope event; Lhasa Block; Lochkovian–Pragian isotope event; South China block; Upwelling

Carbon and conodont apatite oxygen isotope records of Guadalupian-Lopingian boundary sections: Climatic or sea-level signal? - Chen, Bo; Joachimski, Michael; Sun, Yadong; Shen, Shuzhong; Lai, Xulong; Sun, Yadong (Palaeogeography, Palaeoclimatology, Palaeoecology, 2011)
The Guadalupian-Lopingian (G-L) boundary (260.4Ma) is one of the major extinction events in Earth history that coincides with the Emeishan Large Igneous Province and palaeoclimatic changes. Carbon isotopes of whole rock samples were studied in order to document changes in the global carbon cycle. In contrast to earlier studies, we observe no major negative excursion in δ13C in the middle Capitanian. A positive δ13C excursion is observed in the latest Capitanian with a 1.5% increase registered in the J. xuanhanensis Zone to C. postbitteri hongshuiensis Subzone, followed by a decrease of 1% within the C. postbitteri postbitteri Subzone and a 2% decrease in the C. dukouensis to C. asymmetrica Zone. Oxygen isotopes of conodonts from two G-L boundary sections were measured in order to reconstruct conodont habitat and potential changes in water temperature. Oxygen isotope ratios of gondolellid conodonts are higher in comparison to oxygen isotope ratios measured on hindeodid conodonts suggesting that gondollelids lived in cooler and thus deeper waters compared with hindeodids. The oxygen isotope record reconstructed from gondollelid conodonts suggests warming of water temperatures of about 4°C in the late Capitanian (J. postserrata to J. granti Zone), cooling of about 6 to 8°C across the G-L boundary and in the earliest Wuchiapingian, and again significant warming in the Wuchiapingian (C. dukouensis to C. liangshanensis Zone). The temperature increase can be correlated with the main phase of Emeishan volcanism suggesting that climatic warming may have resulted in an intensified hydrological cycle, fertilisation of the oceans and enhanced primary productivity, the latter documented in the positive late Capitanian carbon isotope excursion. However, changes in sea-level seem to parallel reconstructed water temperatures suggesting that changes in water depth in combination with superimposed climatic changes may be responsible for the observed temperature changes. This study documents that oxygen isotope studies on Permian conodonts should be performed on mono-generic conodont samples and that oxygen isotopes not only provide valuable palaeoclimatic information but also may help to constrain the life habitat of conodonts. © 2011 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LG.carbon
Keywords: Carbon and oxygen isotopes; Conodont; Guadalupian; Lopingian; Palaeoclimate

Carbon and nitrogen isotope evidence for widespread presence of anoxic intermediate waters before and during the Permian-Triassic mass extinction - Wu, Baojin; Luo, Genming; Joachimski, Michael; Wignall, Paul; Lei, Lidan; Huang, Junhua; Lai, Xulong (Geological Society of America Bulletin, 2022)
The largest mass extinction since the advent of animals occurred during the Permian-Triassic (P-Tr) transition, ca. 252 Ma, and is commonly attributed to the eruption of the Siberian Traps large igneous province. However, the direct killing mechanism is still debated. In this study, we investigated marine redox conditions of the intermediate water column that most organisms inhabit with special attention to the time interval before the onset of the mass extinction. The carbon isotope composition of carbonate and organic carbon (δ13Ccarb and δ13Corg) as well as the nitrogen isotope composition of bulk nitrogen (δ15N) were analyzed in four P-Tr boundary sequences (Zhongli, Jianshi, Ganxi, and Chaotian sections), which record a transect from a shallow water carbonate platform to a deep water, lower ramp slope in South China. δ13Ccarb shows a distinct negative shift in all sections and displays a clear, 2−4‰, decreasing gradient accompanying an increase in water depth both before and after the mass extinction. A distinct negative shift in δ15N is observed in the shallow water Zhongli section, whereas a minor negative shift is present in the three deeper water sections. Before the mass extinction, the δ15N values from shallow water sections are higher than those from deeper waters. The low δ15N values close to 0‰ in deeper water sections suggest that microbial nitrogen fixation was the predominant source of biologically available nitrogen before the onset of the mass extinction. Thus, the water depth- dependent gradient in δ13Ccarb and δ15N suggests that an oxygen-deficient intermediate water column was already present before the mass extinction. The uniform δ15N values around 0‰ accompanying the onset of the mass extinction reveal that anoxic intermediate waters expanded into shallow waters. Meanwhile, the distinct positive shift in δ13Corg observed in upper ramp slope sections, i.e., the Jianshi and Ganxi sections, suggests that a euxinic photic zone was at least episodically present in the earliest Triassic. The temporal coincidence between the expansion of intermediate water column anoxia and the onset of the P-Tr mass extinction supports the hypothesis that marine anoxia was a direct killing mechanism.

Carbon and oxygen isotope fractionation in the Late Devonian heterocoral Oligophylloides: Implications for the skeletogenesis and evolution of the Heterocorallia - Dworczak, Patrycja Genowefa; López Correa, Matthias; Jakubowicz, Michal; Munnecke, Axel; Joachimski, Michael; Mazzoli, Claudio; Berkowski, Blazej (Palaeogeography, Palaeoclimatology, Palaeoecology, 2022)
The order Heterocorallia is an enigmatic, anatomically distinct group of calcifying Palaeozoic corals with unclear affinities to other, either extinct or modern cnidarian lineages. Here, we present results of microstructure and stable isotope studies on exceptionally well-preserved skeletons of two species of the heterocoral Oligophylloides from the Famennian (Upper Devonian) of the Anti-Atlas, Morocco and the Holy Cross Mountains, Poland. The investigations provide new information on the skeletogenesis and isotope fractionation effects in Palaeozoic heterocorals. In order to estimate the possible role of diagenetic alteration on the observed carbon and oxygen isotope ratios, we have conducted several preservation tests, including transmitted-light, scanning-electron, fluorescence and cathodoluminescence microscopy, Raman spectroscopy, and trace element analyses. The least- and most-altered skeleton portions identified based on this approach are typified by clearly different isotopic signatures. The least-altered parts of the specimens reveal carbon and oxygen isotope ratios close to those of contemporaneous marine-equilibrated calcites. The moderately-pronounced, positive correlations between the δ13C and δ18O values observed for these coralla may reflect relatively minor vital fractionation effects, obscured to some degree by diagenetic overprint. The results suggest that the isotope fractionation mechanisms of the heterocorals differed markedly from the significant kinetic fractionation characteristic of the modern scleractinian corals. Rather, the moderate, if any, extent of non-equilibrium fractionation during skeletogenesis in the Heterocorallia resembled the typical, environmental and metabolic CO2-dominated fractionation effects shown by most other marine calcifiers. These include the extinct rugose corals, modern hydrocorals and, in particular, modern octocorals, with which the heterocorals show notable architectural and structural similarities.<br
Keywords: Heterocorallia; Cnidaria; Carbon and oxygen isotopes; Microstructure; Morocco; Poland

Carbon and oxygen isotope indications for CO2 behaviour after injection: First results from the Ketzin site (Germany) - Myrttinen, Anssi; Becker, Veith; van Geldern, Robert; Wuerdemann, H.; Morozova, D.; Zimmer, M.; Taubald, H.; Blum, Philipp; Barth, Johannes (International Journal of Greenhouse Gas Control, 2010)

Carbon and oxygen isotopic compositions of Silurian brachiopods (Gotland/Sweden): Palaeoceanographic implications. - Wenzel, Bernd; Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 1996)
One hundred and seventy-two non-luminescent brachiopod shells from the Silurian sequence of Gotland were investigated for their carbon and oxygen isotopic composition. Diagenetic alteration of the shell calcite was excluded by means of petrographic, trace element and cathodoluminescence analysis. Oxygen and carbon isotopic signals vary considerably within the uppermost Llandovery to the Ludlow. Average δ18O and δ13C values of well-defined stratigraphic units range from -2.4‰ to -5.9‰ and -1‰ to +8‰, respectively. We observed parallel trends in the carbon and oxygen isotope curves, with the most prominent shifts occurring in the Lower Wenlock, Upper Wenlock and Middle Ludlow. Average δ18O values (-2.4‰ to -2.9‰) recorded in the Middle Ludlow are among the highest δ18O values reported for the Early Palaeozoic. The recorded δ18O variations cannot solely be explained by changes in sea surface temperature and salinity. The variations in the isotopic signals correlate negatively with changes in sea level. Heavy carbon and oxygen signals coincide with sea-level lowstands, whereas light signals are recorded during sea-level highstands. Sea-level highstands were probably characterized by the formation of warm saline waters on subtropical epicontinental shelves, inducing oxygen-deficiency in the basins (alumshale facies). The low δ18O values are attributed to 18O depletion in surface waters owing to the storage of 18O-enriched saline waters in the basins. Low δ13C values are explained by a low surface water productivity, since nutrients were not supplied to the photic zone but rather stored in the deeper ocean. During sea-level lowstands, colder waters that formed in higher latitudes may have represented the main intermediate water source. A better ventilation of the basins is documented by the deposition of well-aerated sediments. Whereas the high δ18O values are explained by the change in oceanic circulation, the high δ13C values are attributed to an enhanced primary productivity and possibly to an enhanced burial of Corg. The model discussed here may provide an attractive scenario for accounting for the recorded short-term variations in the isotopic signals, without the necessity of introducing an isotopic correction factor for Silurian sea water.
UnivIS-Import:2015-03-05:Pub.1996.nat.dgeo.IGM.LG.carbon

Carbon and sulfur cycling during the mid-Ludfordian anomaly and the linkage with the late Silurian Lau/Kozlowskii Bioevent - Frýda, Jiří; Lehnert, Oliver; Frýdová, Barbora; Farkaš, Juraj; Kubajko, Michal (Palaeogeography, Palaeoclimatology, Palaeoecology, 2021)
The Ludfordian (late Silurian) records one of the largest perturbations in the Phanerozoic marine carbon cycling, the mid-Ludfordian positive δ13Ccarb excursion (MLCIEcarb), which occurred in the aftermath of the Lau/Kozlowskii Bioevent (LKB). There are still controversies regarding origin of the MLCIE and its possible causal link(s) with respect to the preceding LKB. Surprisingly, the isotope fractionation of carbon between inorganic and organic carbon pools during the MLCIE was not investigated in detail. To constrain better this parameter of marine C cycle, its linkage to the LKB, and local sulfur cycle, we analysed high-resolution δ13Ccarb, δ13Corg, and δ34Spy records in the Prague Basin (peri-Gondwana) representing one of the most complete records of the MLCIEcarb in the world. Evaluation of these high-resolution δ13Corg and δ13Ccarb records reveals their tight coupling, which in turn indicates the photosynthetic origin of the MLCIEorg via links to primary production and changing rates of organic carbon burial. On the other hand, our data also reveal a short-term decoupling of the δ13Corg and δ13Ccarb records preceding the MLCIE which may have been related to a purported increase in atmospheric pCO2 levels or anoxic event. The peak of the Δ13C anomaly exactly coincides with the LKB and, therefore, for the first time suggests a tight link between the change in marine carbon cycling and the bioevent. Subsequent rapid drop of the Δ13C values (and by inference also atmospheric pCO2) fits well with a rapid cooling and globally documented regression reported for this time interval. Finally, the documented strong coupling of δ13Ccarb and δ34Spy records during the MLCIE points to an intensive microbial sulfate reduction which should increase carbonate alkalinity input, thus contributing to formation of authigenic carbonates and an increase in δ13C values of DIC (and anticipated seawater carbonate saturation). The coupling of δ13Corg and δ34Spy values suggests a global enhancement of organic carbon and pyrite burial likely driven by an expansion of euxinic (anoxic and sulfidic water column) conditions in the oceans. Present study of C and S isotope variations during the MLCIE reveals for the first time a tight link among carbon and sulfur cycling, global cooling, and reorganization of faunal communities and fits well with purported seawater carbonate hypersaturation at the onset and during MLCIE.
CRIS-Team Scopus Importer:2021-02-05
Keywords: Atmospheric CO; Carbon isotopes; Peri-Gondwana; Prague Basin; Redox conditions; Sulfur isotopes

Carbonate budget of a cold-water coral mound (Challenger Mound, IODP Exp. 307) - Titschack, Jürgen; Thierens, M; Dorschel, Boris; Schulbert, Christian; Freiwald, André; Kano, A; Takashima, C; Kawagoe, N; Li, X (Marine Geology, 2009)
Cold-water coral ecosystems represent a worldwide distributed carbonate factory, which is so far not considered in global carbonate budget estimations. The herein presented study evaluates the carbonate budget of a complete cold-water coral mound sequence from Challenger Mound (Belgica Mound Province, Porcupine Seabight, SW offshore Ireland; drilled during IODP Expedition 307) reaching back to the Late Pliocene (< 2.7 Ma) especially focusing on the different carbonate sources (coral-derived aragonite versus background-sediment-derived calcite-dominated carbonate). Cores from adjacent drift deposits were examined for comparison studies. Challenger Mound, which developed in a fast growth phase (unit M1; 2.7 to 1.6 Ma) and a slower growth phase or mound-decline (unit M2; 0.8 Ma until today), separated by a so called 'mound crisis', displays increased carbonate accumulation rates for both phases (17.3 g/(cm2 × ka) for unit M1 and 5.7 g/(cm2 × ka) for unit M2) compared to adjacent drift deposits. But only about 33 to 40 wt.% of the carbonate is derived from corals. Bulk sedimentation rates of on- and off-mound deposits suggest a decline of Challenger Mound since the onset of drift deposition in the area about 1.2 Ma ago. Yet total carbonate accumulation rates as well as hemipelagic Background-Sediment-Derived Carbonate accumulation rates from Challenger Mound (unit M2) still exceed the carbonate accumulation rates of the adjacent drift deposits. The selective enrichment of Background-Sediment-Derived Carbonate (by a factor of 2.0) in a CWC Mound is herein observed for the first time. This might be caused by the different hydrodynamic behaviour and slower settlement of marine fluff rich in calcareous detritus, compared to siliciclastic sediments, and its effective baffling by the coral framework and/or the active catch of the calcareous plankton by the corals. The carbonate accumulation rates of Challenger Mound are about 4 to 12% of the carbonate accumulation rates of tropical shallow-water reefs but exceeds the carbonate accumulation rates of continental slopes by a factor of 3.9 to 11.8. The carbonate production for the entire Belgica Mound Province is estimated with 3.2 × 103 t/a for unit M1 and 1.0 × 103 t/a for unit M2. © 2009 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LP.carbon
Keywords: carbonate budget; carbonate source; Challenger Mound; cold-water coral mound; IODP Expedition 307; NE Atlantic

Carbonate concretions in Miocene mudrocks in NW Algeria: types, geochemistry, and origins - Nemra, Abdelkrim; Ouali Mehadji, Abdelkader; Munnecke, Axel; Belkhedim, Salim; Belkebir, Lahcen (Facies, 2019)
Carbonate concretions have been recorded in many recent and ancient marine sediments around the world. The Middle Miocene marl of the Tenes area, situated in the northeast of the Lower Chelif Basin in NW-Algeria, contains such carbonate concretions but with a variety of different structures and morphologies. Three different basic types are distinguished: nodular (spheroidal, ellipsoidal, disc, and irregular), stratiform, and tubular concretions, the last locally have a central conduit. The close association between carbonate concretions and synsedimentary deformation structures (synsedimentary faults, slumps) and normal faults, pronounced in the Ounsour Anhas outcrop, indicates synsedimentary instability related to upward fluid movement. The concretions were formed by precipitation of micritic carbonate within the host marl at shallow burial depth, probably in the active microbial methanogenesis zone. Strongly varying δ13C values (− 9.82 to + 5.85‰ PDB) are interpreted as the result of the balance between 13C-enriched (residual CO2 from methanogenesis) and 13C-depleted (microbial organic matter decomposition) CO2 added to the pore solutions. δ18O values (− 2.39 to + 1.71‰ PDB) indicate that carbonate concretion growth occurred during early diagenesis conditions, from marine-derived pore-wate

Carbonate mud mounds, conglomerates and sea-level history in the Katian (Upper Ordovician) of central Sweden - Calner, Mikael; Lehnert, Oliver; Joachimski, Michael (Facies, 2010)
The Katian (Upper Ordovician) facies succession of the Siljan district, central Sweden, records some of the most prominent environmental changes in the Ordovician of Baltoscandia. These changes include two separate phases of major sea-level drawdown that were of basinwide and presumably global importance. The first regression and lowstand terminated an entire generation of carbonate mud mounds (the Kullsberg Limestone) and resulted in the formation of polymict carbonate conglomerates (Skålberg Limestone) belonging to the Amorphognathus superbus Zone. New stable isotope data from the Amtjärn quarry shows that this is immediately after the peak of the Guttenberg Carbon Isotope Excursion (GICE), which reaches a δ13C peak value at 3. 3‰ in the uppermost Amorphognathus tvaerensis Conodont Zone. A second major regression and sea-level lowstand is manifested by palaeokarst morphologies in the Slandrom Limestone, which formed close in time to the comparably minor Waynesville positive carbon excursion in the basal Amorphognathus ordovicicus Conodont Zone. The widespread exposure associated with this latter lowstand terminated carbonate production in much of the basin, and, during the subsequent flooding, organic-rich, graptolitic shale formed across most of Baltoscandia. The two corresponding sequence boundaries are amalgamated at the top of truncated carbonate mud mounds in the Siljan district, resulting in a pronounced Middle Katian hiatus in the immediate mound areas. © 2009 Springer-Verlag.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LG.carbon
Keywords: Black shale; Conglomerates; GICE; Glaciation; Katian; Siljan district; Sweden

Carbon cycle in St. Lawrence aquatic ecosystems at Cornwall (Ontario), Canda: Seasonal and spatial variations - Barth, Johannes; et al. (Chemical Geology, 1999)

Carbon isotope chemostratigraphy and precise dating of middle Frasnian (lower Upper Devonian) Alamo Breccia, Nevada, USA - Morrow, J. R.; Sandberg, C. A.; Malkowski, K.; Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 2009)
At Hancock Summit West, Nevada, western USA, uppermost Givetian (upper Middle Devonian) and lower and middle Frasnian (lower Upper Devonian) rocks of the lower Guilmette Formation include, in stratigraphic sequence, carbonate-platform facies of the conodont falsiovalis, transitans, and punctata Zones; the type Alamo Breccia Member of the middle punctata Zone; and slope facies of the punctata and hassi Zones. The catastrophically deposited Alamo Breccia and related phenomena record the 382 Ma Alamo event, produced by a km-scale bolide impact into a marine setting seaward of an extensive carbonate platform fringing western North America. Re-evaluation of conodonts from the lower Guilmette Formation and Alamo Breccia Member, together with regional sedimentologic and conodont biofacies comparisons, now firmly locates the onset of the Johnson et al. (1985) transgressive-regressive (T-R) cycle IIc, which occurred after the start of the punctata Zone, within a parautochthonous megablock low in the Alamo Breccia. Whole-rock carbon isotope analyses through the lower Guilmette Formation and Alamo Breccia Member reveal two positive δ13Ccarb excursions: (1) a small, 3‰ excursion, which is possibly correlative with the falsiovalis Event previously identified from sections in Western Europe and Australia, occurs below the breccia in the Upper falsiovalis Zone to early part of the transitans Zone; and (2) a large, multi-part excursion, dominated by a 6‰ positive shift, begins above the start of the punctata Zone and onset of T-R cycle IIc and continues above the Alamo Breccia, ending near the punctata- hassi zonal boundary. This large excursion correlates with the punctata Event, a major positive δ13C excursion previously recognized in eastern Laurussia and northern Gondwana. Consistent with previous studies, at Hancock Summit West the punctata Event is apparently not associated with any regional extinctions or ecosystem reorganizations. In the study area, onset of the main punctata Event began after the start of both the punctata Zone and T-R cycle IIc, and preceded the Alamo impact by less than 650 k.y., as inferred from conodont biochronologic and regional rock-accumulation rate estimates. Although complicated by the heterolithic, high-energy deposits of the Alamo Breccia, the carbon isotope record of the breccia and post-breccia beds does not indicate a major impact-correlative perturbation to the carbon cycle. This study extends recognition of the punctata Event to western Laurussia, further reinforcing the potential global scale of the event and its potential importance to understanding early to middle Frasnian marine geochemistry and palaeoenvironments. Based on previous models and our observations, increased tectonic activity, increased nutrient flux to oceans, increased marine bioproductivity, widespread anoxia, and increased organic carbon burial were all likely key factors in driving the punctata Event excursion. Furthermore, periodic eustatic and regional relative sea-level rises may have played an important role in promoting organic carbon burial and in maintaining a link between the primary open-marine geochemical signal and that recorded on the shallow-marine, lower Guilmette carbonate platform. © 2009 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2009.nat.dgeo.IGM.LG.carbon
Keywords: Alamo Breccia; Nevada; Carbon isotope chemostratigraphy; Early Late Devonian; Early to middle Frasnian; Punctata Event

Carbon isotope chemostratigraphy and sea-level history of the Hirnantian Stage (uppermost Ordovician) in the Oslo-Asker district, Norway - Calner, Mikael; Bockelie, Johan Fredrik; Rasmussen, Christian M.Ø.; Calner, Hanna; Lehnert, Oliver; Joachimski, Michael (Geological Magazine, 2021)
We present a 13Ccarb chemostratigraphy for the Late Ordovician Hirnantian Stage based on 208 whole-rock samples from six outcrops in the Oslo-Asker district, southern Norway. Our data include the Norwegian type section for the Hirnantian Stage and Ordovician-Silurian boundary at Hovedøya Island. The most complete record of the Hirnantian Isotope Carbon Excursion (HICE) is identified in a coastal exposure at Konglungø locality where the preserved part of the anomaly spans a c. 24 m thick, mixed carbonate-siliciclastic succession belonging to the upper Husbergøya, Langåra and Langøyene formations and where 13Ccarb peak values reach c. +6 ‰. Almost the entire HICE occurs above beds containing the Hirnantia Fauna, suggesting a latest Hirnantian age for the peak of the excursion. The temporal development of the HICE in southern Norway is associated with substantial shallowing of depositional environments. Sedimentary facies and erosional unconformities suggest four inferably fourth-order glacio-eustatically controlled sea-level lowstands with successively increased exposure and erosion to the succession. The youngest erosional unconformity is related to the development of incised valleys and resulted in cut-out of at least the falling limb of the HICE throughout most of the Oslo-Asker district. The fill of the valleys contains the falling limb of the HICE, and the postglacial transgression therefore can be assigned to the latest part of the Hirnantian Age. We address the recent findings of the chitinozoan Belonechitina gamachiana in the study area and its relationship to the first occurrence of Hirnantia Fauna in the studied sections, challenging identification of the base of the Hirnantian Stage.
CRIS-Team Scopus Importer:2021-07-30
Keywords: brachiopods; glaciation; HICE; Hovedøya; incised valley; Konglungø; oolite

Carbon isotope development in the Ordovician of the Yangtze Gorges region (South China) and its implication for stratigraphic correlation and paleoenvironmental change - Zhang, Yuandong; Cheng, Junfeng; Munnecke, Axel; Zhou, Chuanming (Journal of Earth Science, 2010)
This study was supported by the Chinese Academy of Sciences (No. KZCX2-YW-122), the Ministry of Science and Technology (Nos. 2006CB806402, 2006FY1203000-4), and the National Natural Science Foundation of China (No. 40532009).
Keywords: Yangtze region; Carbon Isotopes; Ordovician

Carbon isotope fractionation during abiotic reductive dehalogenation of trichloroethene (TCE) - Bill, Markus; Schüth, Christoph; Barth, Johannes; Kalin, Robert, M. (Chemosphere, 2001)

Carbon isotope fractionation during aerobic biodegradation of trichloroethene by Burkholderia cepacia G4: A tool to map degradation mechanisms - Barth, Johannes; et al. (Applied and Environmental Microbiology, 2002)

Carbon isotope fractionation during reductive dechlorination of TCE in batch experiments with iron samples from reactive barriers - Barth, Johannes; et al. (Journal of Contaminant Hydrology, 2003)

Carbon isotope geochemistry of the Frasnian-Famennian transition - Buggisch, Werner; Joachimski, Michael; Ostertag-Henning, Christian; Pancost, Richard; Freeman, Katherine (Palaeogeography, Palaeoclimatology, Palaeoecology, 2002)
Carbon isotope records for inorganic and total organic carbon (TOC) as well as for individual organic biomarkers show two positive excursions in the Late Frasnian with comparable shape and amplitude in δ13C. The positive shifts in δ13C can be correlated with the deposition of the Kellwasser horizons. The inorganic carbon isotope excursions are explained by an enhanced organic carbon burial that is expected to lower the concentration of oceanic dissolved CO2. TOC δ13C values do not exhibit a larger shift than that recorded by inorganic carbon δ13C values; this is unexpected since a decrease in the dissolved CO2 concentration should result in lower carbon isotope fractionation during photosynthesis (εp). δ13C values of presumed algal biomarkers (low-molecular-weight n-alkanes, pristane, phytane), although offset by ∼2.5‰, exhibit essentially identical records as TOC, and confirm this unexpected result. It is proposed that high atmospheric and oceanic CO2 concentrations during the Devonian resulted in maximum photosynthetic fractionation. Any change in the CO2 concentration would thus not affect εp. As such, δ13C of primary organic carbon and δ13Ccarb will exhibit parallel excursions. The data imply that carbon isotopes and the relationship between εp and [CO2] will not be effective to study changes in pCO2 levels during the Devonian since CO2 concentrations were too high. © 2002 Elsevier Science B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LG.carbon
Keywords: Carbon isotopes; Late Devonian; Mass extinction; Photosynthetic fractionation

Carbon isotope record of Late Cambrian to Early Ordovician carbonates of the Argentine Precordillera - Buggisch, Werner; Lehnert, Oliver; Keller, Martin (Palaeogeography, Palaeoclimatology, Palaeoecology, 2003)
A more than 2000-m-thick Cambrian-Ordovician carbonate platform succession developed on the exotic Argentine Precordillera terrane during rifting from Laurentia and drifting towards Gondwana. On base of these carbonates, a carbon isotope curve could be developed for the Cambrian-Ordovician. We measured δ13Ccarb and δ13Corg values on bulk rocks, selected components and diagenetic cements. Whereas the carbon isotope signals of intertidal and supratidal rocks are altered by diagenesis, most subtidal carbonates exhibit primary marine values. We can report reliable curves for the Middle-Late Cambrian transition and for the latest Cambrian to earliest Middle Ordovician. The δ13C curve matches well with the published data from global Cambrian-Ordovician boundary sections. Excursions and shifts in the carbon isotope curve correspond to events in sequence stratigraphy. This indicates the interdependence on sea level which rules the productivity and/or preservation of organic carbon and therefore the partition between Corg and Ccarb burial. © 2003 Elsevier Science B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2003.nat.dgeo.IGM.LG.carbon
Keywords: Argentina; Cambrian; Carbon isotopes; Ordovician; Precordillera

Carbon isotope records from extant Caribbean and South Pacific sponges: Evolution of δ13C in surface water DIC - Joachimski, Michael; et al. (Earth and Planetary Science Letters, 1996)
Stable isotope records of demosponges from the Caribbean and Coral Sea are described for the purpose of studying the influence of fossil fuel CO on the carbon isotopic composition of dissolved inorganic carbon (DIC) in surface water. The slow-growing sponges precipitate calcium carbonate in isotopic equilibrium with ambient sea water and are used to detect changes in δC from pre-industrial times (early 19th century) to the present. We observed similar shapes and ranges in δC curves measured on Caribbean specimens collected from water depths of 25, 84 and 91 m as well as a specimen collected in shallow waters off New Caledonia. The records reveal a highly significant correlation with atmospheric δC. δC values for Caribbean and Coral Sea surface waters were calculated using the δC sponge records. While δC of atmospheric CO decreased by about 1.4‰ from the early 19th century to 1990, δC of Caribbean and Coral Sea surface waters decreased by 0.9 ± 0.2‰ and 0.7 ± 0.3‰, respectively. No isotopic equilibrium between surface water DIC and atmospheric CO was observed, either during the pre-industrial steady state or during the last 100 years. The lower amount of depletion in the surface water δC with respect to the atmospheric anthropogenic signal is explained by the dilution of the surface waters by biologically altered subsurface water DIC. The lower δC decrease in the Coral Sea points to a stronger influence of the subsurface water source compared to the Caribbean.
Keywords: C-13; Caribbean Sea; Coral Sea; Demospongea

Carbon isotope stratigraphy of the Devonian of Central and Southern Europe. - Buggisch, Werner; Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 2006)
Carbonate rocks of the Rhenohercynian and Saxothuringian zones of the Variscan Mountains, Prague Syncline, Carnic Alps, Montagne Noire, Pyrenees, and Cantabrian Mountains were investigated for δ13Ccarb. The values were measured on bulk carbonate, selected carbonate components and cements. Many of the studied carbonates are interpreted to exhibit primary marine δ13C values with only some showing evidence of diagenetic alteration. A δ13C curve is presented for the entire Devonian time interval. Positive δ13C excursions are documented in the woschmidti-postwoschmidti, sulcatus, kitabicus, Upper serotinus, kockelianus, Middle varcus, falsiovalis, Upper rhenana, linguiformis to Middle triangularis, and Middle to Upper praesulcata conodont Zones. Some excursions are recorded worldwide and interpreted to be of global significance as e.g. at the Silurian-Devonian and Frasnian-Famennian boundaries. Some of the others are described for the first time from Central and Southern Europe, and their global nature has to be verified by further investigations. Most δ13C excursions coincide with sea-level changes and the deposition of black shales. A coupling of changes in sea-level, weathering intensity, nutrient supply, organic carbon production, and climate is assumed as driving force of the carbon isotope excursions. © 2006 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.LG.carbon
Keywords: Bio-events; Black shale; Cantabrian Mountains; Carbon isotopes; Carnic Alps; Devonian; Montagne Noire; Prague Syncline; Rhenohercynian; Saxothuringian

Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central Mozambique - Lüdecke, Tina; Leichliter, Jennifer N.; Aldeias, Vera; Bamford, Marion K.; Biro, Dora; Braun, David R.; Capelli, Cristian; Cybulski, Jonathan D.; Duprey, Nicolas N.; Ferreira da Silva, Maria J.; Foreman, Alan D.; Habermann, Jörg; et al. (Frontiers in Ecology and Evolution, 2022)
The analyses of the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), and oxygen (δ18O) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs. Of these biomaterials, tooth enamel is the hardest, most mineralized vertebrate tissue and therefore least likely to be affected by chemical alteration (i.e., its isotopic composition can be preserved over millions of years), making it an important and widely available archive for biologists and paleontologists. Here, we present the first combined measurements of δ13C, δ15N, and δ18O in enamel from the teeth of modern fauna (herbivores, carnivores, and omnivores) from the well-studied ecosystem of Gorongosa National Park (GNP) in central Mozambique. We use two novel methods to produce high-precision stable isotope enamel data: (i) the “oxidation-denitrification method,” which permits the measurement of mineral-bound organic nitrogen in tooth enamel (δ15Nenamel), which until now, has not been possible due to enamel’s low organic content, and (ii) the “cold trap method,” which greatly reduces the sample size required for traditional measurements of inorganic δ13Cenamel and δ18Oenamel (from ≥0.5 to ≤0.1 mg), permitting analysis of small or valuable teeth and high-resolution serial sampling of enamel. The stable isotope results for GNP fauna reveal important ecological information about the trophic level, dietary niche, and resource consumption. δ15Nenamel values clearly differentiate trophic level (i.e., carnivore δ15Nenamel values are 4.0‰ higher, on average, than herbivores), δ13Cenamel values distinguish C3 and/or C4 biomass consumption, and δ18Oenamel values reflect local meteoric water (δ18Owater) in the park. Analysis of combined carbon, nitrogen, and oxygen stable isotope data permits geochemical separation of grazers, browsers, omnivores, and carnivores according to their isotopic niche, while mixed-feeding herbivores cannot be clearly distinguished from other dietary groups. These results confirm that combined C, N, and O isotope analyses of a single aliquot of tooth enamel can be used to reconstruct diet and trophic niches. Given its resistance to chemical alteration, the analysis of these three isotopes in tooth enamel has a high potential to open new avenues of research in (paleo)ecology and paleontology.
CRIS-Team Scopus Importer:2022-12-23
Keywords: diet; ecology; food webs; savanna; trophic level reconstruction; vertebrate

Carbon, oxygen and strontium isotope records of Devonian brachiopod shell calcite. - Joachimski, Michael; van Geldern, Robert; et al. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2006)
Devonian brachiopod shells from North America, Spain, Morocco, Siberia, China and Germany were analysed for δ13C, δ18O and 87Sr/86Sr. The samples were screened for diagenetic alteration by means of cathodoluminescence, trace element chemistry (Sr, Mn, Fe) and scanning electron microscopy. 409 out of 1678 shells ranging from the middle Emsian to the middle Famennian were accepted as well-preserved. 87Sr/86Sr ratios start with values of 0.70860 in the Lochkovian and decline continuously to 0.70782 at the Emsian-Eifelian boundary. This decrease is attributed to a reduced riverine strontium flux caused by the termination of the Caledonian orogeny. For the Eifelian and Givetian, relatively uniform values between 0.70782 and 0.70784 are observed. 87Sr/86Sr ratios start to rise again in the late Givetian and reach a value of 0.70807 in the early Famennian. An enhanced continental delivery of strontium as consequence of tectonic uplift due to the Eovariscan orogeny, in combination with climatic warming, as suggested by the δ18O record, is interpreted to be responsible for the shift to more radiogenic strontium isotope values. The carbon isotope curve shows four positive δ13C excursions with amplitudes ranging from + 2.0‰ and + 3.5‰. The positive excursion observed in the australis Zone coincides with the deposition of the Bakoven black shale in New York state. The δ13C excursion near the Eifelian-Givetian boundary is correlated with the Kacàk event while the two positive excursions in the late Frasnian and at the Frasnian-Fammenian transition are contemporaneous with the deposition of the Kellwasser horizons. All carbon isotope excursions are interpreted to be the result of increased burial of organic carbon. The oxygen isotope record reveals short-term excursions in the late Givetian, late Frasnian and at the Frasnian-Famennian transition which are interpreted to result from changes in surface water temperature. The long-term evolution in δ18O shows values of - 2.8‰ to - 3.5‰ in the Early and Middle Devonian to generally lower δ18O values between - 4.3‰ and - 6.1‰ in the latest Givetian and Late Devonian. Assuming a δ18O of Devonian seawater of - 1‰ V-SMOW, Early and Middle Devonian δ18O values translate into realistic palaeotemperatures (24 to 27 °C) for tropical to subtropical latitudes. In contrast, the δ18O values of Late Devonian brachiopods indicate a shift to unrealistically warm palaeotemperatures (31 to 41 °C). The change in δ18O of brachiopod calcite cannot be explained solely by a change in temperature, pH or by a secular decrease in δ18O of seawater. A combination of climatic warming and a moderate decrease in δ18O of seawater from the Middle to Late Devonian may account for the observed decrease in δ18O of brachiopod calcite. However, this tentative interpretation is not confirmed by conodont apatite δ18O data that translate into warm but realistic Late Devonian palaeotemperatures. © 2006 Elsevier B.V. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.LG.carbon_0
Keywords: Brachiopods; Carbon isotopes; Devonian; Oxygen isotopes; Strontium isotopes

Carbon, sulfur, oxygen and strontium isotope records, organic geochemistry and biostratigraphy across the Permian/Triassic boundary in Abadeh, Iran - Joachimski, Michael; et al. (International Journal of Earth Sciences, 2004)
Pelagic deposits at Abadeh represent a complete biostratigraphic record across the Permian/Triassic boundary (PTB). The presumed water depth during deposition of these sediments was between 60 and 90 m. Similar to other Permian/Triassic boundary sections, the succession at Abadeh is characterised by a negative carbon isotope shift of approximately 4‰. The values start to decrease in the lower C. changxingensis - C. deflecta s.l. Zone, reach -0.12‰ (V-PDB) in the uppermost Permian just below the PTB, remain low to the early I. isarcica Zone (-0.32‰) and increase subsequently in the upper I. isarcica Zone. For the time interval of the PTB negative carbon isotope excursion, between the C. iranica and the I. isarcica Zones, no correlation exists between the δ13Ccarb δ18Ocarb. The above observations argue against the conclusion of Heydari et al. (2001) that the carbon isotope event at the P/T transition is an alteration artefact and not a global signal. The decrease in δ13Ccarb is accompanied by a ∼5‰ (and potentially up to 10‰) increase in δ34SSSS. Together, these features are thought to reflect a complex global event, notably the development of widespread anoxic oceans with anoxic bottom layers rising onto the shelves. For the carbon isotope drop, other factors, such as the collapse of ocean primary productivity may also have played a role. The 87Sr/86Sr ratios of Dzhulfian seawater show only a minor increase from 0.70705 to 0.70710, reaching 0.70720 in the Dorashamian. The increase becomes steeper in the Early Triassic reaching 0.70754 in the N. dieneri Zone. The rise of the strontium isotope values is thought to be related to enhanced continental weathering under humid climatic conditions in the uppermost Permian (C. meishanensis - H. praeparvus one) and the lack of a dense land vegetation in the Early Triassic, prior to the Spathian (Upper Olenekian). © Springer-Verlag 2004.
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.LG.carbon
Keywords: Abadeh (Iran); Carbon isotopes; Oxygen isotopes; Permian/Triassic boundary; Strontium isotopes; Sulfur isotopes

Carnian–Norian (Late Triassic) climate change: Evidence from conodont oxygen isotope thermometry with implications for reef development and Wrangellian tectonics - Sun, Yadong; Orchard, M. J.; Kocsis, T.; Joachimski, Michael (Earth and Planetary Science Letters, 2020)
The Carnian–Norian (C–N) transition (Late Triassic) has long been postulated as an interval of major climatic changes, though the nature of such changes and their ecological impact remains largely unexplored. We use oxygen isotopes measured on monogeneric conodont assemblages (δ18OPO4) from the Canadian Cordillera to trace seawater temperature evolution at the western margin of Pangea and in the allochthonous Wrangellia Terrane. Different conodont taxa show conspicuous offsets in δ18OPO4, suggesting that they had preferential habitat depths and genus-specific temperature corrections must be applied. Thus, δ18OPO4 from the Williston Lake sections indicates low mid-latitude sea surface temperatures (SSTs) ranging from ∼28 to 35 °C, favouring a generally warm Late Triassic climate scenario. The parvus Subzone of C–N transition, which marks the peak faunal turnover, records major climatic perturbations: SSTs peaking at ∼34 °C then decreasing to ∼29 °C. This is followed by a quick temperature rebound and a second pulse of cooling from 33 to 27 °C in the asymmetrica-Norigondolella Subzone, marking the coldest temperatures in the ∼20 Myr study interval. A secular warming trend towards the late Norian reinstated after the transient cooling in the earliest Norian, coinciding with reef expansions in the Late Triassic. The middle–late Norian (Alaunian 3–Sevatian 1) represents a hothouse climate comparable to the Paleocene–Eocene Thermal Maximum and its warmth supressed both diversity and origination rates of reef-building biota. Early Norian δ18OPO4 data from Frederick Island, Haida Gwaii (part of the Wrangellia Terrane) are more depleted in 18O compared to coeval samples from the Black Bear Ridge, indicating ∼3–5 °C warmer temperatures than the Laurentian epicontinental sea. The temperature difference supports a more southern, probably sub-equatorial position for at least part of the Wrangellia Terrane during the earliest Norian.
CRIS-Team Scopus Importer:2020-01-31
Keywords: faunal turnovers; Late Triassic; palaeoceanography; palaeothemometry; reef development; Wrangellia Terrane

Case studies on the use of temperature-dependent susceptibility for the characterisation of magneto-mineralogical changes during metamorphism - de Wall, Helga; et al. (PHYS CHEM EARTH PT A, 2000)

Cathodoluminescence microscopy and spectroscopy of synthetic ruby crystals grown by the optical floating zone technique - Guguschev, Christo; Goetze, Jens; Göbbels, Matthias (American Mineralogist, 2010)
Synthetic rubies were grown by the optical floating zone method and characterized by cathodolumi-nescence (CL) microscopy and spectroscopy in combination with microprobe analysis. The measured intensity of the Cr 3+-induced CL of corundum is influenced by different parameters such as the sample thickness and orientation, the intensity of the beam current, and the quality of the sample surface. Furthermore, the spectral distribution of the CL emission changes with different concentrations of Cr in the corundum structure. Due to these effects, it is usually not possible to estimate the Cr content directly by using the measured CL intensity. However, we have developed an indirect method that is not significantly affected by these parameters. By using intensity ratios instead of measured intensities, a level of quantification of Cr in natural and synthetic corundum is now possible. Our study shows that the intensity ratio between the N-line at 701.6 nm and the sideband maximum at 713.2 nm displays a nearly linear dependence on the Cr concentration from ca. 100-300 ppm up to ca. 1.1 mol% Cr2O 3. These results give a possible approach to develop an optical-microscope-based CL spectroscopy for quantitative measurements of Cr in natural rubies and synthetic α-Al2O3 materials.
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.LM.cathod
Keywords: α-Al; CL; Crystal growth; Floating zone technique; Quantitative cathodoluminescence; Rubies

Cave finds indicate elk (Alces alces) hunting during the Late Iron Age in the Bavarian Alps - López Correa, Matthias; Pasda, Kerstin; Stojakowits, Philipp; Häck, Bernhard; Prieto, Jérôme; al-Fudhaili, Najat; Mayr, Christoph (E&G : Quaternary Science Journal, 2020)
The finding of a partially preserved elk skeleton from the Bavarian Alps is reported. Remnants of an adult male were found, together with skeletal elements of juvenile moose calves, at the base of a talus cone in the pit cave Stiefelschacht, next to Lenggries (southern Germany). The adult's bones exhibited anthropogenic traces like cut marks and were radiocarbon-dated to the Late Iron Age. A projectile hole in the left shoulder blade and cut marks on the bones are indicative of hunting and meat usage. The elk remains were associated with several wild and domestic species such as ungulates and hare but were not, however, accompanied by archaeological artefacts. Other archaeological sites of the Late Iron Age are so far not known within a distance of less than 30 km to the Stiefelschacht. While the presence of elk during prehistoric times in the Alps has already been known before, the finds and the location are unique in that they are the first evidence of elk hunting during the Late Iron Age in the northern Alp

Cenomanian-Coniacian (Upper Cretaceous) bivalves of the Sergipe Basin, Brazil: Order Pholadomyida - Ayoub-Hannaa, Wagih; Bengtson, Peter; Fürsich, Franz; Andrade, Edilma de Jesus (Revista Brasileira de Paleontologia, 2015)
Twenty-two species of the bivalve order Pholadomyida, belonging to six genera and seven subgenera of the families Pholadomyidae, Pleuromyidae and Poromyidae are described from the Cenomanian–Coniacian Cotinguiba Formation of the Sergipe Basin, north-eastern Brazil. Eleven species, Pholadomya (Ph.) cf. agrioensis Weaver, Ph. (Ph.) kasimiri Pusch, Ph. (Ph.) nodulifera Münster, Ph. (Ph.) occidentalis Morton, Ph. (Procardia) vignesi Lartet, Pleuromya ligeriensis (d’Orbigny), Pl. servesensis Choffat, Liopistha (L.) aequivalvis (Goldfuss), L. (Psilomya) elongata Stanton, L. (P.) globulosa (Forbes) and L. (Sergipemya) gigantea (J. Sowerby) are recorded from the Sergipe Basin for the first time. The new subgenus Sergipemya of the genus Liopistha, family Poromyidae, is erected on the basis of morphological characters such as numerous commarginal ribs, large and highly inflated valves, a well-developed rounded umbonal anterior ridge bordering a deep depression on the anterior part, and the presence of two unequal cardinal teeth with a cardinal tear-shaped socket in the left valve. The pholadomyid fauna of Sergipe closely resembles that of other Tethyan regions in western and southern Europe, northern and western Africa and the Middle East. The distribution patterns of the taxa were probably influenced by east–west-directed currents. Southern Tethyan pholadomyids reached western Africa and north-eastern South America via the Trans-Saharan Seaway.
UnivIS-Import:2017-12-18:Pub.2015.nat.dgeo.IGM.LP.cenoma
Keywords: Pholadomyida; taxonomy; palaeobiogeography; Cretaceous; Cotinguiba Formation; Brazil

Cenomanian (Upper Cretaceous) bivalves from the Hameimat Massifs, north of Tebessa, Algeria: Systematics, biostratigraphy, palaeoecological and taphonomical remarks Bivalves cénomaniens (Crétacé supérieur) des Massifs de Hamiemat, nord de Tébessa, Algérie : Systématique, biostratigraphie, et implications paléoécologiques et taphonomiques - Mendir, Samira; Salmi-Laouar, Sihem; El Qot, Gamal M.; Ayoub-Hannaa, Wagih; Ferré, Bruno (Annales De Paleontologie, 2021)
In the eastern Saharan Atlas, particularly in the northern area of Tebessa Province (NE Algeria), the widely outcropping Cenomanian strata display a highly diversified macrofauna, among which bivalves are prominently represented. Twenty-eight bivalve species are here reported for the first time from the Cenomanian of Hameimat Massifs. Based on the stratigraphic distribution of these bivalves, five bivalve zones were recognized, i.e., Costagyra olisiponensis - Gyrostrea delettrei, Rhynchostreon suborbiculatum - Exogyra conica, Ceratostreon flabellatum, Ilymatogyra africana, and Pycnodonte vesicularis vesiculosa - Rastellum carinatum zones. Correlation to the ammonite biozones of the same region as follows: the Costagyra olisiponensis - Gyrostrea delettrei and the Rhynchostreon suborbiculatum - Exogyra conica zones occur respectively in the Sharpeiceras schlueteri and Mantelliceras saxbii subzones of the lower Cenomanian Mantelliceras mantelli Zone. The Ceratostreon flabellatum Zone is correlated with the middle Cenomanian Acanthoceras rhotomagense Zone. The Ilymatogyra africana Zone is correlated with the upper Cenomanian Calycoceras naviculare and the Metoicoceras geslinianum zones. Finally, the Pycnodonte vesicularis vesiculosa - Rastellum carinatum Zone represents the uppermost Cenomanian. Detailed analysis of biometrical and morphological features of these bivalve specimens provides the most reliable tool within the scope of palaeo-environmental reconstitution and the many palaeo-ecological variables that had driven the development and distribution of these macro-invertebrates. Comparison of these new data to those of adjacent south Tethyian areas supports the homogeneity of the Cenomanian bivalve faunas. Such an affinity underlines more vividly the favorable marine communications and currents driving the geographic dispersal of these bivalves during the Cenomanian.
CRIS-Team Scopus Importer:2021-06-18
Keywords: Algeria.; Biozonation; Bivalves; Cenomanian; Eastern Saharan Atlas; Systematics

Centrifuge modelling of plutons intruding shear zones: Application to the Fürstenstein Intrusive Complex (Bavarian Forest, Germany) - de Wall, Helga; et al. (Geodinamica Acta, 2006)
Keywords: Centrifuge modelling; Emplacement; Plutons; Shear zones

Century-long record of climate change in the subarctic North Pacific Ocean - Joachimski, Michael; et al. (Journal of Geophysical Research F: Earth Surface, 2007)
UnivIS-Import:2015-03-09:Pub.2007.nat.dgeo.IGM.LG.centur

Cephalopoda - Seuß, Barbara; Mapes, Royal H. (IGCP 596 Climate Change and Biodiversity Patterns in the Mid-Palaeozoic, 2016)

Cephalopod palaeobiology: evolution and life history of the most intelligent invertebrates - Klug, Christian; Bonnaud-Ponticelli, Laure; Nabhitabhata, Jaruwat; Fuchs, Dirk; de Baets, Kenneth; Cheng, Ji; Hoffmann, Rene (Swiss Journal of Palaeontology, 2022)
Sigurd von Boletzky was a cephalopod researcher who was world-renowned for his enthusiasm for his field of research, for his friendly and calm personality, and, of course, his publications. He dedicated most of his life as active researcher on the development, biology and evolution of coleoids. Nevertheless, he was always curious to learn about other cephalopods as well. Sigurd passed away in Switzerland on September 28th 2020. We dedicate this text and volume to his memory.
CRIS-Team WoS Importer:2022-06-03

Chaetetids from the Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma - Seuß, Barbara; Senowbari-Daryan, Baba; Nützel, Alexander (Annual Meeting of the Paläontologische Gesellschaft, 2013)
Chaetetid sponges from the Desmoinesian Buckhorn Asphalt Quarry Lagerstätte represent the largest benthic organisms in this outcrop (max. diameter: 21 cm, max. height: 8.3 cm). Deposition of the chaetetid-bearing sediments occurred in a shallow (euphotic zone II-III) marine setting near the palaeo-equator. The siliciclastic-carbonatic sediments from the Lagerstätte were impregnated by migrating hydrocarbons during or shortly after deposition hence, fossil preservation is generally outstanding. Chaetetid skeletons from the quarry originally consisted of high Mg-calcite. Two morphotypes are present, comprising domical and laminar growth, which indicates genetic rather than environmental control. Internal skeletal features comprise tabulae, spine-like projections, pseudoseptae, growth disturbances, and greyish structures. Tubule diameter and length is variable, and spicules are absent. Skeletal fragmentation is common and indicates complex taphonomic mechanisms. Some specimens display large incisions indicating physical impact. The skeletal surface is also often covered by microbial mats associated with Mn-carbonatic cement

Chaetetids from the Upper Carboniferous Buckhorn Asphalt Quarry Lagerstätte, Oklahoma - Seuß, Barbara; Senowbari-Daryan, Baba; Nützel, Alexander (Annual Meeting of the Palaeontological Association, 2013)
Chaetetid sponges from the Desmoinesian Buckhorn Asphalt Quarry Lagerstätte represent the largest benthic organisms in this outcrop (max. diameter: 21 cm, max. height: 8.3 cm). Deposition of the chaetetid-bearing sediments occurred in a shallow (euphotic zone II-III) marine setting near the palaeo-equator. The siliciclastic-carbonatic sediments from the Lagerstätte were impregnated by migrating hydrocarbons during or shortly after deposition hence, fossil preservation is generally outstanding. Chaetetid skeletons from the quarry originally consisted of high Mg-calcite. Two morphotypes are present, comprising domical and laminar growth, which indicates genetic rather than environmental control. Internal skeletal features comprise tabulae, spine-like projections, pseudoseptae, growth disturbances, and greyish structures. Tubule diameter and length is variable, and spicules are absent. Skeletal fragmentation is common and indicates complex taphonomic mechanisms. Some specimens display large incisions indicating physical impact. The skeletal surface is also often covered by microbial mats associated with Mn-carbonatic cement

Challenges and directions in analytical paleobiology - Dillon, Erin; Dunne, Emma; Womack, Tom; Kouvari, Miranta; Larina, Ekaterina; Claytor, Jordan Ray; Ivkić, Angelina; Juhn, Mark; Milla Carmona, Pablo; Robson, Selena Viktor; Saha, Anwesha; Villafaña, Jaime; et al. (Paleobiology, 2023)
Over the last 50 years, access to new data and analytical tools has expanded the study of analytical paleobiology, contributing to innovative analyses of biodiversity dynamics over Earth's history. Despite—or even spurred by—this growing availability of resources, analytical paleobiology faces deep-rooted obstacles that stem from the need for more equitable access to data and best practices to guide analyses of the fossil record. Recent progress has been accelerated by a collective push toward more collaborative, interdisciplinary, and open science, especially by early-career researchers. Here, we survey four challenges facing analytical paleobiology from an early-career perspective: (1) accounting for biases when interpreting the fossil record; (2) integrating fossil and modern biodiversity data; (3) building data science skills; and (4) increasing data accessibility and equity. We discuss recent efforts to address each challenge, highlight persisting barriers, and identify tools that have advanced analytical work. Given the inherent linkages between these challenges, we encourage discourse across disciplines to find common solutions. We also affirm the need for systemic changes that reevaluate how we conduct and share paleobiological research.<br

Challenging asymmetric cements as indicators of vadose diagenesis: “pseudo‑gravitational” cements from the lower Pliensbachian of the Traras Mountains in NW Algeria - Belkhedim, Salim; Munnecke, Axel; Benhamou, Miloud; Nemra, Abdelkrim; Sadji, Radouane (Facies, 2019)

Change in reaction kinetics of a Portland Cement caused by a superplasticizer Calculation of heat flow curves from XRD data - Jansen, Daniel; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Härzschel, Reinhard; Hergeth, Wolf Dieter (Cement and Concrete Research, 2012)
The hydration process of a commercial Portland cement was followed by means of heat flow calorimetry. The measured heat flow was compared with calculated heat flow curves based on XRD data. Examined in particular was the influence of one selected superplasticizer on the hydration of the Portland cement. It was shown that the superplasticizer in question retards both the aluminate reaction and the silicate reaction. It is certainly conceivable that there are more than only one explanation for the interaction between the superplasticizer and the cement. A complexation of Ca 2 + ions from pore solution by the superplasticizer is as thinkable as the adsorption of the polymer on the nuclei or the anhydrous grain surfaces which in turn might lead to the prevention of the growth of the nuclei or the dissolution of the anhydrous grains. © 2011 Elsevier Ltd. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LM.change
Keywords: Hydration; OPC; Superplasticizer; X-ray diffraction

Changes in calcareous nannoplankton assemblages around the Eocene-Oligocene climate transition in the Hungarian Palaeogene Basin (Central Paratethys) - Nyerges, Anita; Kocsis, Ádám; Palfy, Jozsef (Historical Biology, 2020)
The Eocene-Oligocene climate transition (EOT) is the last major greenhouse-icehouse climate state shift in Earth history, ending the warm, ice-free early Palaeogene world and ushering in the Antarctic glaciation. This study is focused on the Hungarian Palaeogene Basin within the Central Paratethys, aiming to characterise the effect of the global cooling event in the calcareous nannoplankton assemblages and to reconstruct the palaeoenvironmental evolution of the region. Calcareous nannoplankton biostratigraphy is focused on documenting the NP21 Zone. Hierarchical cluster analysis allowed us to distinguish five successive assemblages. Thereby defined phases are compared with recently published trends in delta O-18 values and foraminiferal changes. Taxa with a preference for oligotrophic and warm surface waters dominate the lowest assemblage. The next assemblage contains taxa that indicate oligotrophic conditions but temperate surface water at the onset of the EOT. Nannoplankton abundance drops to a minimum in the third phase, when taxa adapted to cool surface waters gradually became dominant. A gradual rebound of nannoplankton abundance is observed in the fourth phase, possibly reflecting regional climate change related to the uplifting Alpine chain. After the end of the EOT, the youngest assemblage includes mostly eurytopic taxa which could tolerate an increased rate of freshwater and terrestrial influx.
CRIS-Team WoS Importer:2020-01-21

Changes in corallite sizes of scleractinian corals across major hyperthermal events - Dimitrijevic, Danijela; Raja Schoob, Nussaibah Begum; Kießling, Wolfgang (Progressive Palaeontology 2021 - Online, 2021)
Global warming today is taking its toll on coral reefs globally, particularly affecting scleractinian corals which rely on their symbionts for nutrition. In the past, hyperthermal events have probably triggered evolutionary losses and gains of symbiosis in corals. Accordingly, we expect photosymbiotic corals to be more strongly affected than non-symbiotic corals. Corallite sizes have been used as a proxy for the efficacy of photosymbiosis with smaller corallite sizes associated with higher photosymbiotic autotrophy in colonial corals. Using a new database on corallite sizes of fossil corals collected from existing literature and data on modern corals from the Coral Trait Database combined with occurrences from the Paleobiology Database, we test how the dependency on photosynthetic diet in corals may have increased their extinction risk. We expect corals to be selected against small corallite sizes during hyperthermal events. Based on a survey of 353 fossil and recent coral genera we establish trends in corallite sizes across the Triassic–Jurassic, Pliensbachian–Toarcian, Barremian–Aptian, Cenomanian–Turonian, and Paleocene–Eocene. We find a significant increase in corallite diameter of all corals at three of these events. Colonial corals had 0.8 times larger corallites in the Aptian than in the Barremian suggesting stronger heterotrophy at this hyperthermal event. However, generalized linear modelling suggests that the extinction of scleractinian corals seems to be non-selective with regards to their corallite sizes. This indicates that processes other than warming, such as increased sediment input could be the cause of this change.<br

Changes in dip of subducted slabs at depth: petrological and geochronological evidence from HP-UHP rocks (Tianshan, NW-China). - Klemd, Reiner; John, Timm; Scherer, E. E.; Rondenay, Stephane; Gao, J. (Earth and Planetary Science Letters, 2011)
High-resolution seismic imaging has previously revealed sudden changes in the dip of subducted oceanic plates. This 'kinking' feature is crucial because in many subduction zones it is thought to coincide with the disappearance of the low-velocity layers associated with subducted oceanic crust. In this study, we present petrological evidence for this phenomenon derived from oceanic blueschist- and eclogite-facies rocks from the Chinese Tianshan. The investigated samples span a large range of peak metamorphic conditions, with temperatures between 330 and 580°C at 1.5 to 2.3GPa. Such variable peak metamorphic conditions, together with the intimate interlayering of high- and ultrahigh-pressure rocks, have also been reported from other Tianshan localities. These observations suggest that the rocks were derived from varying depths within the subduction zone and then juxtaposed during exhumation in the subduction channel. Multi-point Lu-Hf isochrons from four high-pressure rocks yield consistent garnet-growth ages of 313±12, 315.8±2.9, 313.9±4.8, and 315.2±1.6Ma. These, in conjunction with the 311Ma cluster of published 40Ar-39Ar and Rb-Sr white mica ages from the same vicinities imply fast exhumation rates. The Lu-Hf ages confirm that the eclogite-facies metamorphism of the Tianshan high-pressure rocks occurred during a single subduction event in the Late Carboniferous. However, the previously reported peak metamorphic P-T estimates from UHP metasediments and eclogites all lie on a lower geothermal gradient - and thus on a colder P-T path at the slab-wedge interface - than the HP eclogites and meta-volcaniclastic rocks from this study. This suggests that the slab-subduction angle steepened sharply at a depth greater than approximately 90km, i.e., between the depths at which the HP and UHP rocks equilibrated. In addition to the negative buoyancy of mafic UHP rocks in subduction zones, the kinking may act as a geometric hindrance to the exhumation of such rocks, thereby explaining their rarity. © 2011 Elsevier B.V.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.c3geoc.change
Keywords: (U)HP rocks; Lu-Hf geochronology; Oceanic crust; Slab dip steepening; Subduction; Tianshan

Changes in foraminiferal assemblages and environmental conditions during the T-OAE (Early Jurassic) in the northern Lusitanian Basin, Portugal - Reolid, M.; Duarte, L. V.; Rita, Patricia (Palaeogeography, Palaeoclimatology, Palaeoecology, 2019)
The foraminiferal assemblages and other microfossils from the Rabacal area (Maria Pares section) in the Lusitanian Basin (Portugal) provide new insights regarding the Toarcian Oceanic Anoxic Event (T-OAE). Complementary analysis of the delta C-13, total organic carbon (TOC) and geochemical redox and palaeoproductivity proxies reflect environmental changes that affected the microfossil assemblages. Detailed analyses of foraminiferal assemblages (their diversity, abundance, morphogroups and lifestyle) and geochemistry led us to discern phases of the biotic crisis and subsequent stages of recovery. Environmental instability, which began in the lattermost part of the Polymorphum Zone, is marked by a lesser abundance of foraminifera and ostracods, increased opportunist foraminifera, fluctuations in TOC values and the enrichment factor of phosphorous (P-EF), as well as the onset of a negative carbon isotopic excursion (CIE). The peak phase of the biotic crisis corresponds with the lowest values for foraminiferal diversity and abundance (including a barren sample for benthic microfossils). The abundance and diversity of echinoderms, brachiopods, dinoflagellate cysts and calcareous nannofossils dropped sharply during the peak phase. This biotic crisis also entails extinction of the Order Metacopina and a local disappearance of echinoderms and brachiopods. Anoxic conditions at sea bottom did not develop, given the almost continuous record of foraminifera and trace fossils, yet oxygen-depleted conditions occurred. The lower part of the Levisoni Zone contains thin nodular limestones corresponding to a tempestitic-turbiditic facies. In this context, the re-oxygenation of bottom waters was favoured, as indicated by the presence of Thalassinoides and the low values of TOC and redox-sensitive elements (Mo, Ni and U). The survival phase in the wake of the biotic crisis is characterized by greater diversity and abundance of foraminifera and echinoderms (holothuroids and ophiuroids). The lowest delta C-13 values are recorded during this phase, with a dominance of opportunist (Eoguttulina) and facultative opportunist (Paralingulina tenera) foraminifera. Finally, recovery after the biotic crisis is evidenced by high values for specialists and potentially deep infaunal foraminifera, indicating oxic conditions in the sediment.
CRIS-Team WoS Importer:2019-04-16

Changes in physical-thermal properties of soil related to very shallow geothermal systems in urban areas - Di Sipio, Eloisa; Psyk, Mario; Popp, Thomas; Bertermann, David (Geophysical Research Abstracts, Vol. 18, EGU General Assembly 2016, 2016)

Changes in terrestrial floras at the Triassic-Jurassic Boundary in Europe - Barbacka, Maria; Pacyna, Grzegorz; Kocsis, Ádám; Jarzynka, Agata; Ziaja, Jadwiga; Bodor, Emese (Palaeogeography, Palaeoclimatology, Palaeoecology, 2017)
Keywords: Floral change; Hettangian; Plant diversity; Rhaetian

Changing depocentre environments of Palaeolake Olduvai and carbonates as marker horizons for hiatuses and lake-level extremes - Stanistreet, Ian G.; Doyle, Connor; Hughes, Tom; Rushworth, Elisabeth D.; Stollhofen, Harald; Toth, Nicholas; Schick, Kathy; Njau, Jackson K. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2020)
Primary carbonate and marl layers and limestone nodular horizons were intersected in OGCP Boreholes 1A, 2A, 3A, 3B, drilled into the depocentre of Palaeolake Olduvai. The various carbonate types were analysed, employing petrographic (including cathodo-luminescence), stable isotope, and sequence stratigraphic techniques, and recorded important information concerning lake evolution. Primary carbonate and marl layers are preserved at the top of lake deepening cycles (lake-parasequences), marking maximum flooding, followed by lake withdrawal, and then fluvial erosion, leading to the next depositional cycle. Presence of pelagites and a meromict lake favouring anoxic conditions, show it to be not a playa lake, but a deeper fault-bound lake, akin to present day Lake Eyasi. Carbonate and marl layers were exclusively deposited when claystone facies show a geochemical magnesium anomaly associated with a phase of basaltic volcanism affecting the basin, marked by mafic tuffs and basaltic lava flows. Calcium was partitioned into evaporites, such as gypsum/anhydrite, together with the nodular horizons and carbonate soil profiles in the sequence. The resulting high Mg2+/Ca2+ ratio in the lake waters promoted dolomite deposition and replacement, and the formation of aragonite. The nodular horizons yield rainfall isotope values and mark times when the lake was empty and the lake-bed fell under meteoric conditions, precipitating limestone nodules just below the sediment surface under pedogenic vadose, groundwater interface, and groundwater phreatic conditions. The nodular limestone horizons sit below erosional/hiatal surfaces and show vadose micritic and fibrous types to phreatic sparry and other accretionary type textures. Enterolithic to chickenwire textured nodules indicate the pseudomorphing of anhydrite nodules that form beneath salt marshes. Thus, the two carbonate types, primary layers and nodular horizons, provided depth gauges, respectively for the extremes of lake expansion and emptying/drying out. In the case of nodular horizons, the maturity of the carbonate profile gives an indication of the magnitude of the hiatal time gap represented, 1 kyr to 2 kyr for a single horizon to 3 kyr to 9 kyr for more mature soil profiles. Emptying/drying out episodes of Palaeolake Olduvai were not uncommon, and often short-lived. A spectrum of hiatal disconformities in the Olduvai Basin vary from multimillennial hiatuses to mega-disconformities of 40 kyr and 75 kyr.
CRIS-Team Scopus Importer:2020-10-16
Keywords: Dolmicrite layer; Enterolithic nodule; Magnesium anomaly; Micrite limestone; Soil profile; δ

Chapter 3.2b Bransfield Strait and James Ross Island: petrology - Haase, Karsten; Beier, Christoph (Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up, 2021)

Characterisation of deformation and flow mechanics around porphyroclasts in a calcite marble ultramylonite by means of EBSD analysis - Bestmann, Michel; et al. (Tectonophysics, 2006)
Keywords: Calcite; Crystallographic misorientation; Crystallographic preferred orientations (texture); Deformation mechanisms; Electron backscatter diffraction (EBSD); Flow mechanics; Orientation map; Porphyroclast

Characteristic magnetic behavior of subaerial and submarine lava units from the Hawaiian Scientific Drilling Project (HSDP-2) - de Wall, Helga; et al. (Geochemistry Geophysics Geosystems, 2003)
Keywords: HSDP; Magnetic properties; Magnetic susceptibility; Subaerial and submarine lava; Titanomagnetite

Characteristic pattern of species diversity on the canary islands - Steinbauer, Manuel; Beierkuhnlein, Carl (Erdkunde, 2010)
We use an island specific presence/absence data set for the Canary Islands' Arthropoda, Spermatophyta, Fungi, Lichenes, Bryophyta, Mollusca, Chordata, Pteridophyta, Annelida and Nematoda to assess the relative influence of environmental and historical factors on species distribution and endemism. Species richness and the percentage of island endemic species as well as similarity indices for island comparisons were calculated for all species groups. Hierarchical partitioning is used to identify the independent and joined influence of 21 environmental and historical variables. The pattern of species richness is best explained by island elevation. Elevation reflects a variety of factors that contribute to habitat diversity. A similar pattern is detected for the "percentage of single island endemics" (pSIE), a factor associated with speciation. Variables associated with geographical distance have highest explanatory power for biotical similarity of islands. Various Canary Islands species groups show strong distance-decay within the archipelago. According to our findings, speciation is not necessarily driven by species richness or island age alone. Thus, we conclude that correlations between species richness and pSIE, identified in previous studies, could represent an artefact related to differing degrees of isolation between zonal altitudinal ecosystems. This would lead to an increase of speciation with altitude resulting in higher values for pSIE on high altitude islands.
Keywords: Alpha-diversity; Atlantic ocean; Beta-diversity; Distance decay; Island biogeography; Macaronesia; Speciation; Species turn-over; Species-area

Characterization data of reference cement CEM I 42.5 R used for priority program DFG SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials” - Lu, Z. C.; Haist, M.; Ivanov, D.; Jakob, Cordula; Jansen, Daniel; Leinitz, S.; Link, J.; Mechtcherine, V.; Neubauer, Jürgen; Plank, J.; Schmidt, W.; Schilde, C.; et al. (Data in Brief, 2019)
A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program.
CRIS-Team Scopus Importer:2019-11-08
Keywords: Characterization; DFG SPP 2005; Portland cement

Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials” - Lu, Z. C.; Haist, Michael; Ivanov, Dimitri; Jakob, Cordula; Jansen, D.; Schmid, Marlene; Kissling, P. A.; Leinitz, S.; Link, J.; Mechtcherine, Viktor; Neubauer, Jürgen; Plank, J.; et al. (Data in Brief, 2020)
Keywords: Slag; DFG SPP 2005; Cement; Characterization

Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials” - Pott, Ursula; Crasselt, C.; Fobbe, Nicholas; Haist, Michael; Heinemann, M.; Hellmann, S.; Ivanov, Dimitri; Jakob, Cordula; Jansen, Daniel; Lei, Lei; Ran, Li; Julian, Link; et al. (Data in Brief, 2023)
A thorough characterization of base materials is the prerequisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone powder, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and mineralogical composition as well as physical and chemical properties. The data were collected based on tests performed by up to eleven research groups involved in this cooperative program.<br

Characterization of the microstructure of self-leveling compounds (SLC) using 2-dimensional XRD (GADDS). - Seifert, Severin; Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Motzet, Hubert (Proceedings of the Centenary Conference 2008, 2008)
UnivIS-Import:2015-04-16:Pub.2008.nat.dgeo.IGM.LM.charac_4

Charakterisierung der Kalziumaluminatferrat-Mischkristallglieder und Untersuchung des Hydratationsverhaltens - Neubauer, Jürgen; Götz-Neunhoeffer, Friedlinde; Ingrid, Lindner (Schweizerbart und Borntraeger, 2001)
UnivIS-Import:2015-03-09:Pub.2001.nat.dgeo.IGM.LM.charak_6

Charge-separation in uranium diazomethane complexes leading to C-H activation and chemical transformation - Lam, Oanh P.; Feng, P. L.; Heinemann, Frank Wilhelm; O'Connor, John; Meyer, Karsten (Journal of the American Chemical Society, 2008)
The reaction of diphenyldiazomethane with [((ArO) tacn)U] (1) results in an η-bound diphenyldiazomethane uranium complex. This complex exhibits unusual electronic properties as a charge-separated species with a radical anionic open-shell ligand, [((ArO)tacn)U(η- NNCPh)] (2). Treating PhCN with a uranium complex that contains a sterically more demanding adamantane functionalized ligand, [((ArO)tacn)U] (3) results in an unprecedented C-H activation and nitrogen insertion to produce a five-membered heterocyclic indazole complex, [((ArO)tacn)U (η-3-phen(Ind))] (5). X-ray crystallography and spectroscopic characterization of these two compounds show that the [(( ArO)tacn)U(η-NNCPh )] compound is a U(IV) complex with a radical anionic ligand, whereas [((ArO)tacn)U(η-3- phen(Ind))] is a U(IV) f species with a closed-shell ligand. © 2008 American Chemical Society.

CHEAP and safe, an European Project for cheaper and safer low enthalpy geothermal applications. A geological context point of view - Galgaro, Antonio; Bernardi, Adriana; Bertermann, David; de Carli, Michele; Cultrera, Matteo; Della Santa, Giorgia; Di Sipio, Eloisa; Graci, Samantha; Vivarelli, Arianna; Di Tuccio, Maria; Müller, Johannes; Pera, Sebastian; et al. (European Geothermal Congress 2016, 2016)

Cheap-GSHPs, an European project aiming cost-reducing innovations for shallow geothermal installations. - Geological data reinterpretation - Bertermann, David; Müller, Johannes; Cultrera, Matteo; Galgaro, Antonio; Bernardi, Adriana; Di Sipio, Eloisa (Geophysical Research Abstracts, 2016)

Chemical and oxygen isotope composition of gem-quality apatites: Implications for oxygen isotope reference materials for secondary ion mass spectrometry (SIMS) - Sun, Yadong; Wiedenbeck, Michael; Joachimski, Michael; Beier, Christoph; Kemner, Fabian; Weinzierl, Christoph (Chemical Geology, 2016)
Oxygen isotope ratios (δO) of biogenic apatite have become a widely used tool for reconstructing palaeoenvironmental conditions in the past. Ongoing improvements in secondary ion mass spectrometry (SIMS) technology have made in situ δO analyses on sub-nanogram domains within single microfossil samples possible; however this method requires calibration with reference materials (RMs) with a matrix “similar” to that of the samples. Here we evaluated five sources of gem-quality, abiogenic apatites to assess their potentials as SIMS RMs. Our results show that all these gem-quality apatites are low-REEs calcium fluorapatites with δO values between 6.6 and 11.4‰. Large variations in δO have been found for between crystals from a single deposit as well as within individual crystals. Durango apatite has an inter-crystal δO range of 4.4‰ (6.6–11.0‰, N = 9 crystals). Madagascar Green apatite, Madagascar 1st Mine apatite and Ipira apatite have inter-crystal variations in δO of 4.1‰ (7.3–11.4‰, N = 15 crystals), 3.5‰ (7.6–11.1‰, N = 9 crystals) and 3.1‰ (7.1–10.2‰, N = 11 crystals), respectively. South Africa Blue apatite has a smaller inter-crystal δO range of only 0.9‰ (8.7–9.6‰, N = 6 crystals), though this might be an artefact due to the restricted number of samples studied. Intra-crystal δO variations of studied crystals generally range from 0.8 to 1.8‰. However, several gem apatite crystals from Madagascar have minor δO variation within 0.5‰ and represent most promising candidate RM. Gem-quality abiogenic apatites can be used as RMs for calibrating SIMS δO analyses, however these require homogeneity testing at sub-millimetre scale in advance. Durango crystals, commonly used as RMs in earlier SIMS-based studies, display a conspicuous heterogeneity in δO, with intra-crystal variations ranging from 0.7 to 2‰ as detected by both gas source isotope ratio mass spectrometry and large geometry SIMS. Thus, Durango apatite cannot be considered as suitable for SIMS calibration and alternative reference materials need to be sought.
Keywords: Apatite; Durango; Oxygen isotope; Secondary ion mass spectrometry

Chemical characterisation is rough: the impact of topography and measurement parameters on energy-dispersive X-ray spectroscopy in biominerals - Shirley, Bryan; Jarochowska, Emilia (Facies, 2022)
Energy dispersive X-ray microscopy (EDX) is a widely available, inexpensive method of characterizing the in-situ elemental composition of samples in Earth and life sciences. Common protocols and textbooks focussing on material sciences address EDX analysis of metallic samples that can be polished perfectly, whereas geoscientists often investigate specimens with prominent topography and composed of light, difficult to resolve elements. This is further compounded by the scarcity of literature surrounding the methodology of SEM-EDX in the field of palaeontology, leading to common misinterpretations and artefacts during data acquisition. Here, the common errors in elemental composition obtained with EDX arising from surface topography and from parameters subject to user decisions are quantified. As a model, fossil bioapatite (conodonts) and abiotic Durango apatite are used. It is shown that even microscale topography can distort measured composition by up to 34%, whereas topographic features such as tilt with respect to the electron beam lead to differences of up to 85%. Working distance was not the most important parameter affecting the results and led to differences in composition of up to 13%, whereas the choice of standard and its levelling with the sample surface led to inaccuracy reaching 33%. EDX results can be also affected by beam damage and the effects of acceleration voltage on sample acquisition and resolution are quantified. An estimate is provided of the severity of errors associated with samples which cannot satisfy preparation requirements for EDX fully, such as holotypes, and with user decisions. Using a palaeontological example, recommendations are offered for the best parameters and the relative importance of error sources are assessed.
CRIS-Team WoS Importer:2022-04-08

Chemical evolution of calc-alkaline magmas during the ascent through continental crust: constraints from Methana, Aegean arc - Schönhofen, Milena; Wölki, Dominic; Haase, Karsten; Beier, Christoph; Regelous, Marcel (Journal of Petrology, 2020)

Chemostratigraphy - Weissert, Helmut; Joachimski, Michael; Sarnthein, Michael (Newsletters on Stratigraphy, 2008)
Chemostratigraphy uses chemical fingerprints stored in sediments and sedimentary rocks for stratigraphic correlation. Stable isotope signatures fixed in sedimentary inorganic and organic matter are among the most powerful proxies used in chemostratigraphy. This contribution focuses on the use of oxygen and carbon isotope geochemistry in stratigraphy. The importance of oxygen isotope stratigraphy for paleoclimate research is documented in case study I. Oxygen isotope stratigraphy can be used to trace climate pulses through the last few million years. It serves also as a tool for reconstruction of multicentennial climate variations on a global scale. Case study II demonstrates how carbon isotope stratigraphy in Cretaceous successions is used for correlation between ammonite-dated sections and sections dated with magnetostratigraphy. Case study III focuses on the use of carbon isotope stratigraphy in the Palaeozoic. Carbon isotope studies have been intensively used in the Palaeozoic to unravel changes in the global carbon cycle and for chemostratigraphic correlation of sections from various palaeocontinents. However, diagenesis is a major concern since Palaeozoic carbonates may have been affected by recrystallisation and considerably higher temporal overprint in comparison to Mesozoic or Cenozoic carbonate sequences.
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LG.chemos

Chemotrophy-based phosphatic microstromatolites from the Mississippian at Drewer, Rhenish Massif, Germany - Zwicker, Jennifer; Smrzka, Daniel; Gothieu, Matthias; Libowitzky, Eugen; Joachimski, Michael; Ernst Böttcher, Michael; Peckmann, Jörn (Geological Magazine, 2023)
The Drewer quarry located in the Rhenish Massif is a well-studied outcrop that comprises Upper Devonian (Famennian) to Lower Carboniferous (Viséan) strata. Within the Drewer deposits two black shale intervals have been described that are linked to two global oceanic anoxic events, the Hangenberg Event and the Lower Alum Shale Event. The black shales associated with the Middle Tournaisian Lower Alum Shale Event contain abundant phosphatic concretions, which were investigated using thin section petrography, powder X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscopy. The concretions formed during several growth phases under anoxic and at least episodically sulphidic conditions within the sediment and served as a substrate for subsurface microbial mats that formed phosphatic microstromatolites. The microstromatolites occur either as partially branched columns of up to 600 μm in length attached to the phosphatic concretions or as smaller, bulbous aggregates surrounding the concretions. Element mapping identified the presence of pyrite and other metal sulphides within the phosphatic microstromatolites. The carbon and oxygen stable isotopic composition of phosphate-associated carbonate within the phosphatic microstromatolites suggests that the mat-forming microorganisms were probably anaerobic, chemotrophic microbial communities dwelling in the anoxic environment during the Lower Alum Shale Event. Such interpretation agrees with the deeper-water depositional setting of the Lower Alum Black Shale and its high content of organic matter, suggesting that chemotrophic microbial mats are potent agents of phosphogenesis in general, and of the formation of phosphatic stromatolites in particular.
CRIS-Team Scopus Importer:2023-09-15
Keywords: Devonian-Carboniferous Boundary; Lower Alum Black Shale; phosphogenesis; Rhenish Massif; stromatolites

Chitinozoan biostratigraphy and carbon isotope stratigraphy from the Upper Ordovician Skogerholmen Formation in the Oslo Region. A new perspective for the Hirnantian lower boundary in Baltica - Amberg, Chloé E. A.; Vandenbroucke, Thijs R.A.; Nielsen, Arne Thorshøj; Munnecke, Axel; Mclaughlin, Patrick I. (Review of Palaeobotany and Palynology, 2017)
The end-Ordovician has received wide attention because it hosts major global events including mass extinctions, glaciations, significant sea-level fluctuations, and large-scale perturbations of the Earth's carbon cycle. Knowing the order and timing of these events and their components is crucial for understanding these environmental changes. Here, we use stable carbon isotope stratigraphy in combination with chitinozoan biostratigraphy to correlate the Upper Ordovician Belonechitina gamachiana chitinozoan Biozone. Its position has long been a matter of debate; some argue that it is of late Katian age and others that it is of early Hirnantian age. The Skogerholmen Formation from the Oslo-Asker District in Norway has been correlated with the lower-middle Pirgu Baltic Stage, hitherto believed to correspond to the international upper Katian Stage. Our study, however, reveals the presence of B. gamachiana, diagnostic of the eponymous Biozone, in the descending trend of a modest carbon isotope excursion in the lower part of this formation. This is strikingly similar to data from coeval end-Ordovician sections in North America, where the prevailing evidence suggests an early Hirnantian age for the B. gamachiana chitinozoan Biozone. This new correlation suggests that the lower Hirnantian boundary may be positioned within the Pirgu Baltic Stage.
Keywords: Baltica; Biostratigraphy; Carbon isotopes; Chitinozoans; End-Ordovician; Hirnantian

Chitinozoan biostratigraphy at the Late Ordovician GICE event in the Borenshult-1 Drillcore (Sweden). - Pouille, Lauren; Delabroye, Aurelian; Vandenbroucke, Thijs R.A.; Calner, Michael; Lehnert, Oliver; Vecoli, Marco; Danelian, Taniel (Review of Palaeobotany and Palynology, 2013)
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.chitin

CHRONOLOGY OF THE UNIQUE ANGRITE NORTHWEST AFRICA 10463 - Reger, P. M.; Zhang, B.; Gannoun, A. M.; Regelous, Marcel; Agee, C. B.; Bouvier, A. (METEORITICS & PLANETARY SCIENCE, 2021)
CRIS-Team WoS Importer:2021-09-10

Chronosphere: Earth System History Variables - Kocsis, Ádám; Raja, Nussaïbah Begum (GSA 2020 Connects Online, 2020)
Researchers focusing on global-scale ecological and evolutionary patterns are faced with the overwhelmingly increasing volume and diversity of data compilations. The complexity of the relevant research questions necessitates the interconnected use of multiple datasets (the source variables) that are often regularly updated. Finding these data and incorporating them in the analytical workflow can be time consuming and often lead to difficulties and conflicts in version control. The goal of the ‘chronosphere’ project is to offer a portal to these data and to allow their immediate use by compiling frequently accessed representations on a server that keeps track of different versions. These data are available through an R package of the same name (available on the CRAN servers), that downloads a specific version of a dataset and attaches it to the R environment. The project focuses on data used in biogeography, macroecology and macroevolution, from large datasets to small tables published as supplementary information to research articles. Currently available data include major sources such as the Paleobiology Database, the PaleoReefs Database, and the paleogeographic reconstructions of the PaleoMAP project. ‘chronosphere’ will also be used to distribute the output of BRIDGE HadCM3L family deep-time climate models. To facilitate the use of deep-time spatial data, the R package includes functions that utilize either the GPlates Web Service or the GPlates desktop application to reconstruct the positions of present-day coordinates and spatial features using a user-specified reconstruction model. An efficient container class is also implemented to facilitate the work with raster and vector data layers that are organized in multi-dimensional arrays. These features were proven especially useful in the classroom environment, where the fast download and transformation of data are important. Providing data in a consistent form within the R programming framework, ‘chronosphere’ allows the fast reproducibility, and ultimately the tracing of scientific results with the same codebas

Chronostratigraphy and age modeling of Pleistocene drill cores from the Olduvai Basin, Tanzania (Olduvai Gorge Coring Project) - Deino, Alan L.; Heil, Clifford; King, John; McHenry, Lindsay J.; Stanistreet, Ian G.; Stollhofen, Harald; Njau, Jackson K.; Mwankunda, Joshua; Schick, Kathy D.; Toth, Nicholas (Palaeogeography, Palaeoclimatology, Palaeoecology, 2020)
Keywords: Tephrostratigraphy; Magnetostratigraphy; East Africa; Bayesian; 40Ar/39Ar dating

Climate change and marine life - Richardson, Anthony J; Brown, Christopher D.; Brander, Keith; Bruno, John F.; Buckley, Lauren; Burrows, Michael T.; Duarte, Carlos M.; Halpern, Benjamin S.; Hoegh-Guldberg, Ove; Holding, Johnna; Kappel, Carrie V.; Kießling, Wolfgang; et al. (Biology Letters, 2012)
A Marine Climate Impacts Workshop was held from 29 April to 3 May 2012 at the US National Center of Ecological Analysis and Synthesis in Santa Barbara. This workshop was the culmination of a series of six meetings over the past three years, which had brought together 25 experts in climate change ecology, analysis of large datasets, palaeontology, marine ecology and physical oceanography. Aims of these workshops were to produce a global synthesis of climate impacts on marine biota, to identify sensitive habitats and taxa, to inform the current Intergovernmental Panel on Climate Change (IPCC) process, and to strengthen research into ecological impacts of climate change.
Keywords: climate change; marine science; detection and attribution

Climate change and the latitudinal selectivity of ancient marine extinctions - Reddin, Carl James; Kocsis, Ádám; Kießling, Wolfgang (Paleobiology, 2018)
Geologically rapid climate change is anticipated to increase extinction risk nonuniformly across the Earth's surface. Tropical species may be more vulnerable than temperate species to current climate warming because of high tropical climate velocities and reduced seawater oxygen levels. To test whether rapid warming indeed preferentially increased the extinction risk of tropical fossil taxa, we combine a robust statistical assessment of latitudinal extinction selectivity (LES) with the dominant views on climate change occurring at ancient extinction crises. Using a global data set of marine fossil occurrences, we assess extinction rates for tropical and temperate genera, applying log ratios to assess effect size and Akaike weights for model support. Among the classical “big five” mass extinction episodes, the end-Permian mass extinction exhibits temperate preference of extinctions, whereas the Late Devonian and end-Triassic selectively hit tropical genera. Simple links between the inferred direction of climate change and LES are idiosyncratic, both during crisis and background intervals. More complex models, including sampling patterns and changes in the latitudinal distribution of continental shelf area, show tropical LES to be generally associated with raised tropical heat and temperate LES with global cold temperatures. With implications for the future, our paper demonstrates the consistency of high tropical temperatures, habitat loss, and the capacity of both to interact in generating geographic patterns in extinctions.<br
Keywords: marine invertebrates; Phanerozoic; Paleobiology Database; model selection; generalized least squares; habitat loss; temperature related stressors

Climate change disrupts core habitats of marine species - Hodapp, Dorothee; Roca, Irene T.; Fiorentino, Dario; Garilao, Cristina; Kaschner, Kristin; Kesner-Reyes, Kathleen; Schneider, Birgit; Segschneider, Joachim; Kocsis, Ádám; Kießling, Wolfgang; Brey, Thomas; Froese, Rainer (Global Change Biology, 2023)
Driven by climate change, marine biodiversity is undergoing a phase of rapid change that has proven to be even faster than changes observed in terrestrial ecosystems. Understanding how these changes in species composition will affect future marine life is crucial for conservation management, especially due to increasing demands for marine natural resources. Here, we analyse predictions of a multiparameter habitat suitability model covering the global projected ranges of >33,500 marine species from climate model projections under three CO2 emission scenarios (RCP2.6, RCP4.5, RCP8.5) up to the year 2100. Our results show that the core habitat area will decline for many species, resulting in a net loss of 50% of the core habitat area for almost half of all marine species in 2100 under the high-emission scenario RCP8.5. As an additional consequence of the continuing distributional reorganization of marine life, gaps around the equator will appear for 8% (RCP2.6), 24% (RCP4.5), and 88% (RCP8.5) of marine species with cross-equatorial ranges. For many more species, continuous distributional ranges will be disrupted, thus reducing effective population size. In addition, high invasion rates in higher latitudes and polar regions will lead to substantial changes in the ecosystem and food web structure, particularly regarding the introduction of new predators. Overall, our study highlights that the degree of spatial and structural reorganization of marine life with ensued consequences for ecosystem functionality and conservation efforts will critically depend on the realized greenhouse gas emission pathway.
CRIS-Team Scopus Importer:2023-03-03
Keywords: climate change; climate projections; environmental niche models; habitat suitability; marine biodiversity; RCP

Climate Change, Water Resources and Pollution in the Ebro Basin: Towards an Integrated Approach - Barth, Johannes; et al. (Springer, 2010)

Climate signals in carbon isotope series from Pinus nigra ssp. laricio in Corsica - Szymczak, Sonja; Joachimski, Michael; Bräuning, Achim; Hetzer, Timo; Kuhlemann, Joachim (TRACE - Tree Rings in Archaeology, Climatology and Ecology, Vol. 10: Proceedings of the DENDROSYMPOSIUM 2011 Scientific Technical Report STR 12/03, GFZ Potsdam, 2012)
UnivIS-Import:2015-04-20:Pub.2011.nat.dgeo.IG.zentr.climat_7

Climate velocity and the future global redistribution of marine biodiversity - Molinos, Jorge G.; Halpern, Benjamin S.; Schoeman, David S.; Brown, Christopher D.; Kießling, Wolfgang; Moore, Pippa J.; Pandolfi, John; Poloczanska, Elvira S.; Richardson, Anthony J; Burrows, Michael T. (Nature Climate Change, 2016)
Anticipating the effect of climate change on biodiversity, in particular on changes in community composition, is crucial for adaptive ecosystem management but remains a critical knowledge gap. Here, we use climate velocity trajectories, together with information on thermal tolerances and habitat preferences, to project changes in global patterns of marine species richness and community composition under IPCC Representative Concentration Pathways (RCPs) 4.5 and 8.5. Our simple, intuitive approach emphasizes climate connectivity, and enables us to model over 12 times as many species as previous studies. We find that range expansions prevail over contractions for both RCPs up to 2100, producing a net local increase in richness globally, and temporal changes in composition, driven by the redistribution rather than the loss of diversity. Conversely, widespread invasions homogenize present-day communities across multiple regions. High extirpation rates are expected regionally (for example, Indo-Pacific), particularly under RCP8.5, leading to strong decreases in richness and the anticipated formation of no-analogue communities where invasions are common. The spatial congruence of these patterns with contemporary human impacts highlights potential areas of future conservation concern. These results strongly suggest that the millennial stability of current global marine diversity patterns, against which conservation plans are assessed, will change rapidly over the course of the century in response to ocean warming.
UnivIS-Import:2016-06-01:Pub.2016.nat.dgeo.IGM.LP.climat
Keywords: Climate-change ecology

Climate vs. topography - spatial patterns of plant species diversity and endemism on a high-elevation island - Irl, Severin D. H.; Harter, David E. V.; Steinbauer, Manuel; Gallego Puyol, David; Maria Fernandez-Palacios, Jose; Jentsch, Anke; Beierkuhnlein, Carl (Journal of Ecology, 2015)
Keywords: Canary Islands; Climatic rarity; Climatic stability; Island ecology; Landscape ecology; Landscape scale; Mini-continent; Multimodel inference; Spatial ecology

Climate warming, euxinia and carbon isotope perturbations during the Carnian (Triassic) Crisis in South China - Sun, Yadong; Wignall, P. B.; Joachimski, Michael; Bond, D. P. G.; Grasby, S. E.; Lai, X. L.; Wang, L. N.; Zhang, Z. T.; Sun, S.; Sun, Yadong (Earth and Planetary Science Letters, 2016)
The Carnian Humid Episode (CHE), also known as the Carnian Pluvial Event, and associated biotic changes are major enigmas of the Mesozoic record in western Tethys. We show that the CHE also occurred in eastern Tethys (South China), suggestive of a much more widespread and probably global climate perturbation. Oxygen isotope records from conodont apatite indicate a double-pulse warming event. The CHE coincided with an initial warming of 4 °C. This was followed by a transient cooling period and then a prolonged 7 °C warming in the later Carnian (Tuvalian 2). Carbon isotope perturbations associated with the CHE of western Tethys occurred contemporaneously in South China, and mark the start of a prolonged period of carbon cycle instability that persisted until the late Carnian. The dry-wet transition during the CHE coincides with the negative carbon isotope excursion and the temperature rise, pointing to an intensification of hydrologic cycle activities due to climatic warming. While carbonate platform shutdown in western Tethys is associated with an influx of siliciclastic sediment, the eastern Tethyan carbonate platforms are overlain by deep-water anoxic facies. The transition from oxygenated to euxinic facies was via a condensed, manganiferous carbonate (MnO content up to 15.1 wt%), that records an intense Mn shuttle operating in the basin. Significant siliciclastic influx in South China only occurred after the CHE climatic changes and was probably due to foreland basin development at the onset of the Indosinian Orogeny. The mid-Carnian biotic crisis thus coincided with several phenomena associated with major extinction events: a carbonate production crisis, climate warming, δC oscillations, marine anoxia, biotic turnover and flood basalt eruptions (of the Wrangellia Large Igneous Province).
Keywords: Carbon isotopes; Carnian Humid Episode; Climate warming; Large igneous provinces; Marine anoxia; Wrangellia flood basalt

Climatic, depositional and environmental controls on early carbonate cementation in fluvial and shallow marine sandstones - Janßen, Meike; Caracciolo, Luca; Bonnell, L. M.; Lander, R. H.; Munnecke, Axel; Beltrán-Triviño, A.; Muto, F.; Stollhofen, Harald (Marine and Petroleum Geology, 2023)
Sandstones with carbonate cements are found in a variety of depositional settings (e.g. fluvial, lacustrine, deltaic, shallow marine) with abundances ranging from just a few volume percent to pervasive pore-filling cements and are of major interest due to their impact on reservoir quality. Despite the widespread occurrence of such cements, predictive models for eogenetic carbonate cementation have yet to be developed. Hence, investigations on the controls and distribution of early carbonate precipitation are necessary to improve the accuracy of predictions of the nature and distribution of diagenetic alterations. We conducted a petrological and petrophysical analysis of early near-surface carbonate cementation in siliciclastic and mixed siliciclastic-carbonate sandstones from fluvial and shallow marine environments to reconstruct eogenetic processes and their associated controls. Furthermore, sediment burial scenarios up to a loading of 50 MPa were simulated with the reservoir quality prediction software Touchstone to evaluate the impact of carbonate cements on the compaction behaviour of the rocks. Results highlight the importance of climate, depositional environment and detrital composition and texture in regards to the precipitation processes of near-surfaces carbonate cements and burial development. Our data shows that the presence and distribution of early carbonate cements reflects a complex interaction of several parameters, such as the composition and texture of detrital material in the source area, the availability and infiltration of meteoric or marine waters and the presence of precursor carbonate during deposition. Burial simulations demonstrate the strengthening effect of early carbonate cementation and its influence on the development of intergranular volume and porosity during burial with up to five times less porosity loss due to compaction than without near-surface cementation.
CRIS-Team Scopus Importer:2023-09-01
Keywords: Carbonate cementation; Intergranular volume; Mixed siliciclastic-carbonate sediments; Near-surface diagenesis; Reservoir quality

Climatic fluctuations and seasonality during the Late Jurassic (Oxfordian-Early Kimmeridgian) inferred from d18O of Paris Basin oyster shells. - Brigaud, Benjamin; Puceat, Emmanuelle; Pellenard, Pierre; Vincent, Benoit; Joachimski, Michael (Earth and Planetary Science Letters, 2008)
UnivIS-Import:2015-03-09:Pub.2008.nat.dgeo.IGM.LG.climat

Climatic ups and downs in a disturbed Jurassic world - Dera, Guillaume; Brigaud, Benjamin; Monna, Fabrice; Laffont, Remi; Puceat, Emmanuelle; Deconinck, Jean-Francois; Pellenard, Pierre; Joachimski, Michael; Durlet, Christophe (Geology, 2011)
The tropical, warm, and equable climate of the Jurassic world is regularly challenged by geoscientists, especially since oxygen isotopes (δ18O) of fossil hardparts have been used to reconstruct the paleotemperature history of seawater. By applying the innovative "SiZer" (significant zero crossings of the derivatives) statistical approach to a newly compiled δ18O database for the Jurassic, we demonstrate the occurrence of major and multiscale δ18O changes mainly related to climate disturbances. For the first time, two long-term anomalies in δ18O are identified during the Toarcian and the Late Jurassic, in conjunction with intensive volcanism in large igneous provinces. These results support a strong influence of repeated volcanic pulses on the modulation of pCO2, temperatures, and polar ice cap volumes over protracted periods. At shorter time scales, 13 relatively rapid (0.5-1 m.y.) and significant warming and cooling events are identified, the causes of which include transient fluctuations in greenhouse gas concentrations related to still-debated mechanisms. © 2011 Geological Society of America.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LG.climat

Climatic warming in the latest Permian and the Permian-Triassic mass extinction. - Joachimski, Michael; Lai, Xulong; Shen, Shuzhong; Jiang, Haishui; Luo, Genming; Chen, Bo; Chen, Jun; Sun, Yadong; Sun, Yadong (Geology, 2012)
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.LG.climat

Clinker quality control using combined methods; A study using microscopy and X-ray techniques Especially Rietveld Method - Pöllmann, Herbert; Neubauer, Jürgen; König, Uwe; Motzet, Hubert (19th International Conference on Cement Microscopy, 1997)
UnivIS-Import:2015-04-16:Pub.1997.nat.dgeo.IGM.LM.clinke

Clusterung der oberflächennahen thermischen Leitfähigkeit und anderer Bodenparameter – Erdkabelkorridorplanung aus geothermischer Sicht - Bertermann, David; Müller, Johannes; Stegner, Johannes; Schwarz, Hans (Der Geothermie Kongress 2019, 2019)
Für in Planung befindliche 700-800 km lange Erdkabelkorridore für Hochspannungs-Gleichstrom-Übertragungs-Leitungen eines großen Übertragungsnetzausbauprogramms galt es im Rahmen der Studie „Thermische Bodenclusterung“ diverse bodenphysikalische und klimatische Parameter mit Bedeutung für die Auslegung der Erdkabel zu ermitteln beziehungsweise zu modellieren. Diese Untersuchung dient u. a. der Früherkennung von Divergenzen der thermischen Eigenschaften des Bodenkörpers, um mögliche Substratverbesserungen einplanen und schlussendlich einen reibungslosen Betrieb der erdverlegten Kabel gewährleisten zu können. Auf der projektierten Strecke wird mit einer horizontal gebohrten Strecke von bis zu 2000 km gerechnet, da auf der Trasse mehrere parallel verlaufende Erdkabel verbaut werden. Auch aus diesem Grund ist es unerlässlich, eine adäquate, an den Untergrund angepasste Planung zu verfolgen. Im Fokus der Studie stand die Ermittlung der Wärmeleitfähigkeit des Bodens in Abhängigkeit der Tiefe und damit der Lagerungsdichte sowie des Wasserhaushalts der jeweiligen Bodenart. Insgesamt wurden die Klima- und Bodenparameter Bodenart, Bodenklassen nach DIN 18300, Festgesteinsart, Festgesteinstiefe, klimatische Wasserbilanz, Grundwasserflurabstand, Bodenfeuchteregime, van Genuchten Parameter für die teilgesättigte Wasserleitfähigkeit, Bodenfrosttage sowie die thermische Leitfähigkeit von Böden und Festgesteinen untersucht und geclustert. Hierzu wurden für potenzielle Untersuchungsräume der Korridorverläufe digitale Flächen- und Bohrdaten von den jeweiligen Landesämtern, sowie bundesweite Klimadaten verwendet. Alle Daten sind in einer Geodatenbank implementiert und mit einem Geoinformationssystem (GIS) prozessiert und interpoliert worden. Um die Daten auf einer sich über 6 Bundesländer erstreckende Fläche (< 6200 km²) zu analysieren, mussten definierte Tiefenstufen deklariert und die Datenangaben vereinheitlicht werden. Damit die einzelnen Datensätze wie beispielsweise der Grundwasserflurabstand oder die Festgesteinstiefe mit korrekter Höhenrelation im GIS eingebettet werden können, wurden diese zudem in ein digitales Geländemodell überführt. Mit Hilfe der Flächendaten von Boden- und Klimakarten lagen generell für den oberflächennahen Bodenbereich Informationen über das gesamte Untersuchungsgebiet vor. Es wurde festgelegt, dass die digitalen Flächendaten der Bodenkarten entsprechend ihres Gültigkeitsbereichs als Input für den oberflächennahen Tiefenbereich von 0-1 m dienen. Lediglich beim Auftreten von Datenlücken wurden zusätzlich Informationen aus Bohrprofilen hinzugezogen. Für die tieferen Horizonte > 1 m unter Geländeoberkante ergeben sich die Informationen ausschließlich aus interpolierten Bohrdaten. Da mit steigender Endteufe die Anzahl vorliegender Bohrinformationen abnimmt, sinkt in tieferen Bereichen > 5 m die Datendichte sukzessive. So beinhalten für die Tiefenstufe 5-10 m nur 74,6 % der untersuchten Bohrungen überhaupt noch Informationen. In 10-20 m Tiefe können nur noch 54,3 % der Bohrungen für die Interpolation herangezogen werden. Eine abschließende Validierung der ermittelten Werte erfolgte durch einen Vergleich mit Informationen dreier Baugrunduntersuchungen innerhalb eines Referenzprojektes. Die Daten der Baugrunduntersuchungen dienten zudem als Benchmark, wodurch im Nachgang eine Modelloptimierung vorgenommen werden konnte. Eine weitere Verifizierung der Ergebnisse kann im Zuge des Bauvorhabens an den tatsächlich vorliegenden Böden mit einem Messaufbau wie z. B. nach Drefke et al. (2017) durchgeführt werden. Generell nehmen Wassergehalt und Lagerungsdichte mit zunehmender Tiefe zu, was mit einem Anstieg der effektiven Lagerungsdichte und des Matrixpotentials einhergeht. Ebenso verhält sich die direkt von diesen Parametern beeinflusste Wärmeleitfähigkeit. Diese wurde anhand von zwei unterschiedlichen Konzepten nach Kersten (1949) / Farouki (1981) und nach Markert et al. (2017) / Lu et al. (2014) berechnet. Mit Hilfe der in dieser Studie erstellten, georeferenzierten Datenbank können Auswertungen und projektspezifische Abfragen zur thermischen Leitfähigkeit sowie zu anderen pedologischen und klimatischen Parametern über das extensive Untersuchungsgebiet des Stromübertragungsnetzes durchgeführt werden. Die gewonnenen Ergebnisse lassen sich zudem vorbehaltlos auf Fragestellungen des Themenbereichs oberflächennaher bzw. oberflächennahester Geothermiesysteme wie Kollektoren bzw. deren Sonderformen wie Grabenkollektoren oder Erdkörbe übertragen und können u. a. die Planungssicherheit dieser Systeme erhöhen.
Keywords: Thermische Leitfähigkeit; physikalische Bodeneigenschaften; Erdkabel; Klimadaten

Coalification history of the Stephanian Ciñera- Matallana pull- part basin, NW Spain: Combining anisotropy of vitrinite reflectance and thermal modelling - de Wall, Helga; et al. (International Journal of Earth Sciences, 2004)
The Stephanian Cinera-Matallana Basin of NW Spain comprises 1,500 m of alluvial to lacustrine coal-bearing sediments, which were deposited in a late Variscan transtensional/transpressional pull-apart setting. The relationship between coalification pattern and rock deformation was evaluated by measurements of the anisotropy of vitrinite reflectance (AVR). The AVR ellipsoids reveal both pre-tectonic elements related to the bedding fabric and syn-tectonic elements related to folding, producing biaxial ellipsoid shapes with the maximum reflectance parallel to fold axes. The mean coalification gradient for the Stephanian succession is about 0.62 %Rr/km. Calculations of the mean palaeogeothermal gradient are presented on the basis of three different empirical equations. A palaeo-geothermal gradient of 85 degreesC/km is considered the most realistic, with an overburden of about 1,000 m. 1-D numerical modelling of the burial history results in two possible scenarios, the most preferable involving a palaeo-heat flow of 150 mW/ m 2 and an overburden of ca. 1,050 m. These results indicate that maximum coalification was related to a localised but high palaeo-heat flow/-geothermal gradient. The anisotropy of vitrinite reflectance highlights the interactive and transitional nature of sedimentary compaction and rock deformation on the maturation of organic material within strike-slip fault zones.
UnivIS-Import:2015-03-09:Pub.2004.nat.dgeo.IGM.c3tekt.ectono
Keywords: Anisotropy of vitrinite reflectance; Ciñera-Matallana; Coalification; Palaeo-geothermal gradient; Palaeo-heat flow

co-As mineralization at the mining district Bou Azzer-El Graara Inlier, Anti-Atlas, Morocco. - Pätzold, Jürgen; Klemd, Reiner; Joachimski, Michael (Zeitschrift für Angewandte Geologie, 2010)
UnivIS-Import:2015-03-09:Pub.2010.nat.dgeo.IGM.c3geoc.coasmi

Coastal upwelling drives intertidal assemblage structure and trophic ecology - Reddin, Carl James; Docmac, Felipe; Bothwell, John; Harrod, Chris; et al. (PLoS ONE, 2015)

Coexisting carbonate-bearing eclogite and blueschist in SW Tianshan, China: Petrology and phase equilibria. - Li, Jilei; Klemd, Reiner; Gao, Jun; Meyer, Melanie (Journal of Asian Earth Sciences, 2012)
Carbonate-bearing eclogite and blueschist coexist in the same lithological sequence in the Tianshan (ultra-)high-pressure/low-temperature metamorphic belt, northwestern China. Both of them consist of the mineral assemblage garnet+omphacite+dolomite±magnesite+phengite±paragonite+epidote/clinozoisite+glaucophane±barroisite/(Mg-)katophorite+rutile/titanite+pyrite. The eclogite has an omphacite content of ca. 43vol.% and a glaucophane content of <1vol.%. In contrast, the blueschist has an omphacite content of <8vol.% and a glaucophane content of ca. 43vol.%. The blueschist occurs as bands or interlayers in the eclogite. Lawsonite pseudomorphs of epidote/clinozoisite+paragonite assemblages in garnet are commonly observed in the eclogite and blueschist. High carbonate contents in oceanic metabasalts suggest that the precursor basaltic crust has undergone significant hydrothermal alteration prior to subduction. Mineral assemblages and textures show that the omphacite-carbonate-bearing blueschist and the carbonate-bearing eclogite underwent an identical metamorphic evolution. Phase equilibrium modeling in the TiNCaKFMASCHO system further indicates that both the carbonate-bearing eclogite and the omphacite-bearing blueschist equilibrated at peak metamorphic conditions of 540-565°C and 21.8-23.1kbar. Under these conditions calculated X CO2 isopleths reveal the presence of a mainly aqueous fluid phase (X CO20.02) for the coexisting eclogite and omphacite-bearing blueschist. The stability of the high-pressure mineral assemblages in the eclogite and the omphacite-bearing blueschist is due to differences of the respective bulk-rock composition (the CaO content in particular). This study suggests that three different kinds of blueschist were formed during subduction and exhumation of the South Tianshan oceanic crust, including prograde blueschist formed prior to eclogitization, retrograde blueschist formed by rehydration of eclogite during exhumation in the subduction channel, and coexisting blueschist with eclogite under peak metamorphic conditions. © 2012 Elsevier Ltd.
UnivIS-Import:2015-03-09:Pub.2012.nat.dgeo.IGM.c3geoc.coexis
Keywords: Coexistence; Eclogite; Omphacite-bearing blueschist; Pseudosection; Tianshan (ultra-)high-pressure/low-temperature belt

Collapse of Late Permian chert factories in the equatorial Tethys and the nature of the Early Triassic chert gap - Yang, F.; Sun, Y. D.; Frings, P. J.; Luo, L.; E, J. W.; Wang, L. N.; Huang, Y. F.; Wang, T.; Müller, Johann; Xie, S. C. (Earth and Planetary Science Letters, 2022)
Permian chert successions were geographically extensive, spanning from the palaeoequator to the northern high latitudes. Large-scale chert production was abruptly terminated in the latest Permian, resulting in a multi-million-year “chert gap” in the Early Triassic. In order to constrain the tempo of chert production changes and understand their nature, we combine proxy data with Si box model analyses and focus on the Talung Formation of South China—the most representative Upper Permian siliceous unit in the equatorial Tethys. Two deepwater sections from the northern margin of the Yangtze Platform were investigated, showing that bedded cherts had already become less common in the Clarkina changxingensis conodont zone. The waning of chert production coincided with water column deoxygenation and an increase in carbonate and siliciclastic components in the late Changhsingian. The final collapse of the chert factory in South China predated the negative δ13C excursion and climate warming but coincided with a sharp decrease in primary productivity. Together with Si box model output, we suggest that warming-induced expansion of the oceanic dissolved silica inventory (and decrease in burial efficiency) alone cannot maintain a multi-million-year chert gap. Instead, a loss of siliceous biomass during the end-Permian crisis is the primary cause of the Early Triassic chert demise.
CRIS-Team Scopus Importer:2022-11-04
Keywords: chert gap; conodont; end-Permian mass extinction; Si box model; Talung Formation

Colonial history and global economics distort our understanding of deep-time biodiversity - Raja Schoob, Nussaibah Begum; Dunne, Emma; Matiwane, Aviwe; Khan, Tasnuva Ferdous Ming; Nätscher, Paulina; Ghilardi, Aline Marcele; Chattopadhyay, Devapriya (Nature Ecology & Evolution, 2021)
Sampling biases in the fossil record distort estimates of past biodiversity. However, these biases not only reflect the geological and spatial aspects of the fossil record, but also the historical and current collation of fossil data. We demonstrate how the legacy of colonialism and socioeconomic factors, such as wealth, education and political stability, impact the global distribution of fossil data over the past 30 years. We find that a global power imbalance persists in palaeontology, with researchers in high- or upper-middle-income countries holding a monopoly over palaeontological knowledge production by contributing to 97% of fossil data. As a result, some countries or regions tend to be better sampled than others, ultimately leading to heterogeneous spatial sampling across the globe. This illustrates how efforts to mitigate sampling biases to obtain a truly representative view of past biodiversity are not disconnected from the aim of diversifying and decolonizing our discipline.

Colonialism shaped today’s biodiversity - Raja, Nussaïbah Begum (Nature Ecology & Evolution, 2022)
CRIS-Team Scopus Importer:2022-10-28

Colospongia cribriforma nov. sp. and Parastylothalamia minima nov. sp. ("Sphinctozoa", Porifera) from the Norian of Taurus Mountains, Turkey - Senowbari-Daryan, Baba; Link, Michael; Riedel, Peter (Revue de Paléobiologie, 2015)
Two chambered hypercalcified sponges, Colospongia cribrifera nov. sp. and Parastylothalamia minima nov. sp. are described from the Norian reef boulders exposed around the town of Terziler, Taurus Mountains, south Turkey. Colospongia cribrifera is characterized by partly perforated and partly imperforated chamber walls and additionally sieve-like plates or cribribulla in the chamber exowalls. Parastylothalamia minima is one of the smallest chambered sponge known in the fossil record. The siphonate sponge is characterized by evenly perforated chamber walls and by scattered pillars within the chamber interiors.
UnivIS-Import:2017-11-07:Pub.2015.nat.dgeo.IGM.LP.colosp
Keywords: Colospongia; Parastylothalamia; Triassic; Norian; Reef; Taurus Mountains; Turkey

Combined Analytical Py-GC-MS, SEM, FTIR and C-13 NMR for Investigating the Removal of Trace Metals from Aqueous Solutions by Biochar - De Andrade, Mineia A. M.; Monteiro, Adnivia S. C.; Gontijo, Erik S. J.; De Castro Bueno, Carolina; Macedo, Joao C. A.; Rangel, Elidiane C.; Melo, Darllene S.; Montero, Jose I. Z.; Rosa, Andre H. (Journal of the Brazilian Chemical Society, 2020)
In this study, the efficiency of biochar (BC) produced from sugarcane bagasse at different pyrolysis temperatures (300, 400, 500 and 600 degrees C) for simultaneous removal of Cd-II, Pb-II, Cu-II, Cr-III, Ni-II and Zn-II ions from aqueous solutions was assessed. All BC were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR). C-13 nuclear magnetic resonance (C-13 NMR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The effects of pyrolysis temperature, initial adsorbate concentration and adsorbent dosage on adorption capacity of BC were examined through batch experiments. The BC efficiency was also evaluated after a desorption cycle. The maximal adsorptions (C-II: 51.50%. Crm: 74.35%. Cu-III: 91.18%, Ni-II: 47.05%. Pb-II: 96.17% and Zn-II: 40.50%) were observed for BC produced at 500 degrees C, probably because of its higher porosity and presence of functional groups detected by SEM and FTIR. The maximum adsorption capacity for Cd-II, Cr-III, Cu-II, Ni-II and Zn-II (ions fitted to Langmuir model) were 175, 303, 455. 156 and 128 mu g g(-1). respectively. The predominance of phenolic groups observed in Py-GC-MS data may explain the high percentage of multi-element removal. Experimental data were best fitted to pseudo-second order, Sips and Freundlich models. The BC presented good removal results after a desorption cycle.
CRIS-Team WoS Importer:2020-06-30

Combined heat and power from hydrothermal geothermal resources in Germany: An assessment of the potential - Eyerer, S.; Schifflechner, C.; Hofbauer, S.; Bauer, Wolfgang; Wieland, C.; Spliethoff, H. (Renewable & Sustainable Energy Reviews, 2020)
This study investigates the potential of hydrothermal geothermal energy for combined heat and power (CHP) generation in Germany. Based on the theoretical potential of hydrothermal heat in place, the technical and economic potential is determined with a review and an analysis of existing geothermal plants. To this end, the thermodynamic and economic performance of operating power plants is analyzed and models for the efficiency and the production costs are developed. Based on this analysis, a technical potential of 12.2PWh el and 16.7PWh th as well as an economic potential of 9.1PWhel and 12.5PWhth is determined. In order to derive an annual contribution from the economic potential, the regeneration of the resource is taken into account. Considering a sustainable exploitation rate, an annual economic potential of 9.1TWhel/a and 12.5TWhth/a is derived. This corresponds to a share of 1.51% of the gross electricity demand and a share of 1.48% of the demand for space heating and domestic hot water. This analysis provides a profound review about the existing geothermal power plants and their thermodynamic and economic performance. Furthermore, the assessment of the geothermal potential in Germany is necessary for political decision making, particular with a view towards future adjustments of the feed-in tariffs defined by the Renewable Energy Act.
CRIS-Team Scopus Importer:2019-12-24
Keywords: Binary power plants; Combined heat and power generation; Economic potential; Geothermal energy; Levelized costs of electricity; Technical potential

Combined radiolarian-ammonite stratigraphy for the Late Jurassic of the Antarctic Peninsula: Implications for radiolarian stratigraphy - Kießling, Wolfgang; Scasso, Roberto A.; Zeiss, Arnold; Riccardi, Alberto; Medina, Francicso A. (Geodiversitas, 1999)
New biostratigraphic data from co-occurring radiolarians and ammonites in Upper Jurassic sequences of the Antarctic Peninsula (Byers Peninsula on Livingston Island and Longing Gap, Graham Land), permit a revised and more refined regional stratigraphy. The new data also allow a revision of the chronostratigraphic assignment of some American radiolarian zones established by Pessagno and collaborators: The boundary of Zone 3-4 is assigned to the latest Kimmeridgian, contrasting the former assignment to the early/late Tithonian boundary. The boundary between Subzone 4 beta and 4 alpha is assigned to the early Tithonian, but was usually correlated with the early late Tithonian/late late Tithonian boundary. The new chronostratigraphic data from Antarctica are used together with recent results of Baumgartner and collaborators to revise the age assignment of the North American Late Jurassic radiolarian zones.
UnivIS-Import:2015-03-05:Pub.1999.nat.dgeo.IGM.LP.combin
Keywords: Biostratigraphy; Micropalaeontology; Cephalopods

Combining wood anatomy and stable isotope variations in a 600-year multi-parameter climate reconstruction from Corsican black pine - Szymczak, Sonja; Hetzer, Timo; Bräuning, Achim; Joachimski, Michael; Leuschner, Hanns-Hubert; Kuhlemann, Joachim (Quaternary Science Reviews, 2014)
We present a new multi-parameter dataset from Corsican black pine growing on the island of Corsica in the Western Mediterranean basin covering the period AD 1410-2008. Wood parameters measured include tree-ring width, latewood width, earlywood width, cell lumen area, cell width, cell wall thickness, modelled wood density, as well as stable carbon and oxygen isotopes. We evaluated the relationships between different parameters and determined the value of the dataset for climate reconstructions. Correlation analyses revealed that carbon isotope ratios are influenced by cell parameters determining cell size, whereas oxygen isotope ratios are influenced by cell parameters determining the amount of transportable water in the xylem. A summer (June to August) precipitation reconstruction dating back to AD 1185 was established based on tree-ring width. No long-term trends or pronounced periods with extreme high/low precipitation are recorded in our reconstruction, indicating relatively stable moisture conditions over the entire time period. By comparing the precipitation reconstruction with a summer temperature reconstruction derived from the carbon isotope chronologies, we identified summers with extreme climate conditions, i.e. warm-dry, warm-wet, cold-dry and cold-wet. Extreme climate conditions during summer months were found to influence cell parameter characteristics. Cold-wet summers promote the production of broad latewood composed of wide and thin-walled tracheids, while warm-wet summers promote the production of latewood with small thick-walled cells. The presented dataset emphasizes the potential of multi-parameter wood analysis from one tree species over long time scales. © 2014 Elsevier Ltd.
UnivIS-Import:2015-04-14:Pub.2014.nat.dgeo.IGM.LG.combin
Keywords: Carbon isotopes; Climate reconstruction; Mediterranean; Oxygen isotopes; Pinus nigra; Tree ring anatomy

Comment on Maravelis et al. “Accretionary prism–forearc interactions as reflected in the sedimentary fill of southern Thrace Basin (Lemnos Island, NE Greece)” - Caracciolo, Luca; et al. (International Journal of Earth Sciences, 2017)

Community recommendations for geochemical data, services and analytical capabilities in the 21st century - Klöcking, Marthe; Wyborn, Lesley; Lehnert, Kerstin A.; Ware, Bryant; Prent, Alexander M.; Profeta, Lucia; Kohlmann, Fabian; Noble, Wayne; Bruno, Ian; Lambart, Sarah; Ananuer, Halimulati; Barber, Nicholas D.; et al. (Geochimica Et Cosmochimica Acta, 2023)
The majority of geochemical and cosmochemical research is based upon observations and, in particular, upon the acquisition, processing and interpretation of analytical data from physical samples. The exponential increase in volumes and rates of data acquisition over the last century, combined with advances in instruments, analytical methods and an increasing variety of data types analysed, has necessitated the development of new ways of data curation, access and sharing. Together with novel data processing methods, these changes have enabled new scientific insights and are driving innovation in Earth and Planetary Science research. Yet, as approaches to data-intensive research develop and evolve, new challenges emerge. As large and often global data compilations increasingly form the basis for new research studies, institutional and methodological differences in data reporting are proving to be significant hurdles in synthesising data from multiple sources. Consistent data formats and data acquisition descriptions are becoming crucial to enable quality assessment, reusability and integration of results fostering confidence in available data for reuse. Here, we explore the key challenges faced by the geo- and cosmochemistry community and, by drawing comparisons from other communities, recommend possible approaches to overcome them. The first challenge is bringing together the numerous sub-disciplines within our community under a common international initiative. One key factor for this convergence is gaining endorsement from the international geochemical, cosmochemical and analytical societies and associations, journals and institutions. Increased education and outreach, spearheaded by ambassadors recruited from leading scientists across disciplines, will further contribute to raising awareness, and to uniting and mobilising the community. Appropriate incentives, recognition and credit for good data management as well as an improved, user-oriented technical infrastructure will be essential for achieving a cultural change towards an environment in which the effective use and real-time interchange of large datasets is common-place. Finally, the development of best practices for standardised data reporting and exchange, driven by expert committees, will be a crucial step towards making geo- and cosmochemical data more Findable, Accessible, Interoperable and Reusable by both humans and machines (FAIR).
CRIS-Team Scopus Importer:2023-05-19
Keywords: Data quality; Data standards; FAIR data

Comparative Evaluation of Wild and Farmed Rainbow Trout Fish Based on Representative Chemosensory and Microbial Indicators of Their Habitats - Mahmoud, Mohamed A. A.; Magdy, Mahmoud; Tybussek, Thorsten; Barth, Johannes; Buettner, Andrea (Journal of Agricultural and Food Chemistry, 2023)
Wild and farmed rainbow trout were compared with chemical profiling, chemosensory properties, carbon concentration and isotope analyses, 1-and 2-GC/O-MS, GC-FID, and aroma profile analyses. Results were linked with the prokaryotic and eukaryotic microbiological profile of the fish sources using multivariate statistical analysis. Fish from natural environments proved to have better sensory properties in terms of fruity, sweet, and citrusy attributes, compared to farmed fish. However, the farmed fish were found to have higher nutritional value based on their lipid contents. These differences might relate to the introduction of feed extrudates, which could influence the overall quality of fish products. Thereby, malodor episodes linked to musty/earthy off-odor notes related to odorants including geosmin, beta-caryophyllene, (E,Z)-2,4-nonadienal, and (E,E)-2,4-nonadienal. These compounds, in turn, correlated with Asticcacaulis benevestitus, Curvibacter sp., Albidiferax sp., Aquabacterium commune, and Aquabacterium citratiphilum abundance and were further affected by oxygen levels in the water column.
CRIS-Team WoS Importer:2023-02-24

Comparing calcite and phosphate oxygen isotope paleothermometers - d18O of Silurian brachiopods and conodonts - Joachimski, Michael; et al. (Geochimica Et Cosmochimica Acta, 2000)
Oxygen isotope compositions of Silurian calcitic brachiopod shells from Gotland are compared with those of phosphatic inarticulate brachiopod shells and conodonts from identical stratigraphic horizons. The δO(phosphate) values of inarticulate brachiopod shells vary widely (13.0 to 17.5‰ V-SMOW) and are significantly lower than those of coeval conodont samples (17.5 to 19.5‰ V-SMOW). Conodont samples from individual beds have homogenous δO(phosphate) values with variations close to the analytical precision (±0.2‰). Together with a significant correlation of conodont δO(phosphate) and articulate brachiopod shell δO(carbonate) values (r = 0.85), this observation suggests that primary marine oxygen isotope compositions are better preserved in conodont apatite than in inarticulate brachiopod shell apatite. However, with decreasing δO(carbonate) values, the δO(phosphate) values of conodonts are higher than expected for theoretical isotopic equilibrium with brachiopod calcite. Different habitats of conodonts and brachiopods cannot account for the observed offset in δO because both organisms were thriving on a broad shallow marine carbonate platform. Whereas δO(phosphate) values of Silurian conodonts are close to δO(phosphate) values of modern and Mesozoic tropical biogenic apatites, most Silurian calcitic brachiopod shells from Gotland are depleted in O when compared to modern or Mesozoic brachiopods. We therefore suggest that Silurian conodonts from Gotland record paleotemperature and δO of Silurian sea water more faithfully than coeval calcitic brachiopod shells. Copyright (C) 2000 Elsevier Science Ltd.
UnivIS-Import:2015-03-09:Pub.2000.nat.dgeo.IGM.LG.compar

Comparing oxygen isotope records of Silurian calcite and phosphate-δ18O compositions of brachiopods and conodonts - Joachimski, Michael; et al. (Geochimica Et Cosmochimica Acta, 2000)
Oxygen isotope compositions of Silurian calcitic brachiopod shells from Gotland are compared with those of phosphatic inarticulate brachiopod shells and conodonts from identical stratigraphic horizons. The δO(phosphate) values of inarticulate brachiopod shells vary widely (13.0 to 17.5‰ V-SMOW) and are significantly lower than those of coeval conodont samples (17.5 to 19.5‰ V-SMOW). Conodont samples from individual beds have homogenous δO(phosphate) values with variations close to the analytical precision (±0.2‰). Together with a significant correlation of conodont δO(phosphate) and articulate brachiopod shell δO(carbonate) values (r = 0.85), this observation suggests that primary marine oxygen isotope compositions are better preserved in conodont apatite than in inarticulate brachiopod shell apatite. However, with decreasing δO(carbonate) values, the δO(phosphate) values of conodonts are higher than expected for theoretical isotopic equilibrium with brachiopod calcite. Different habitats of conodonts and brachiopods cannot account for the observed offset in δO because both organisms were thriving on a broad shallow marine carbonate platform. Whereas δO(phosphate) values of Silurian conodonts are close to δO(phosphate) values of modern and Mesozoic tropical biogenic apatites, most Silurian calcitic brachiopod shells from Gotland are depleted in O when compared to modern or Mesozoic brachiopods. We therefore suggest that Silurian conodonts from Gotland record paleotemperature and δO of Silurian sea water more faithfully than coeval calcitic brachiopod shells. Copyright (C) 2000 Elsevier Science Ltd.

Comparing Phase Development and Rheological Properties of OPC Paste Within the First Hour of Hydration - Jakob, Cordula; Jansen, Daniel; Pott, Ursula; Neubauer, Jürgen (Rheology and Processing of Construction Materials, 2020)
In this paper the very early hydration of ordinary Portland cement at 20 °C and 30 °C is investigated, focussing on the first hour after the addition of water. The development of the rheological behaviour of cement paste during hydration is compared with the kinetics determined by quantitative in-situ X-ray diffraction (QXRD) and heat flow calorimetry. For both temperatures the cumulative heat correlates very well with the evolution of ettringite content over the first hour of hydration. The precipitation rate of ettringite is strongly influenced by temperature. This results in a higher formation rate of ettringite already in the first minutes after mixing at 30 °C. Analogously the temperature affects the rheological behaviour of the cement paste. The measured torque values are also higher for 30 °C from the first point of investigation on. Furthermore, the increasing torque can be linked to the rise in the ettringite content at both temperatures. The formation of other hydrate phases influencing the development of the rheological behaviour within the observed time frame cannot be proven with the data at hand. Therefore, it can be assumed that ettringite content is the determining mineral for the early workability of cement pastes.
CRIS-Team Scopus Importer:2019-10-22
Keywords: Ettringite formation; Hydration kinetics; OPC; Rheology; Temperature

Comparing the nature of the western and eastern Azores mantle - Genske, Felix S.; Beier, Christoph; Stracke, Andreas; Turner, Simon P.; Pearson, Norman J.; Hauff, Folkmar; Schaefer, Bruce F.; Haase, Karsten (Geochimica Et Cosmochimica Acta, 2016)
The Azores islands in the central North-Atlantic originate from a regional melting anomaly, probably created by melting hot, unusually hydrous and geochemically enriched mantle. Here, we present Hf, Pb and Os isotopic data in geochemically well-characterised primitive lavas from the islands Flores and Corvo that are located west of the Mid-Atlantic Ridge (MAR), as well as submarine samples from a subsided island west of Flores and from Deep Sea Drilling Project (DSDP) holes drilled in the western part of the Azores platform and beyond. These are compared to existing data from the Azores islands east of the MAR. The geodynamic origin of the two islands west of the ridge axis and furthest from the inferred plume centre in the central part of the plateau is enigmatic. The new data constrain the source compositions of the Flores and Corvo lavas and show that the western and eastern Azores mantle is isotopically similar, with the exception of an enriched component found exclusively on eastern São Miguel. Trace element ratios involving high field strength elements (HFSE) are distinctly different in the western islands (e.g. twofold higher Nb/Zr) compared to any of the islands east of the MAR. A similar signature is observed in MAR basalts to the south of the Azores platform and inferred to originate from (auto-) metasomatic enrichment of the sub-ridge mantle (Gale et al., 2011, 2013). In a similar fashion, low degree melts from an enriched source component may metasomatise the ambient plume mantle underneath the western Azores islands. Melting such a modified plume mantle can explain the chemical differences between lavas from the western and eastern Azores islands without the need for additional plume components. Recent re-enrichment and intra melting column modification of the upwelling mantle can cause local to regional scale geochemical differences in mantle-derived melts.

Comparison between Measured and Calculated Thermal Conductivities within Different Grain Size Classes and Their Related Depth Ranges - Bertermann, David; Müller, Johannes; Freitag, Simon; Schwarz, Hans (Soil Systems, 2018)
In the field of the efficiency of very shallow geothermal energy systems, there is still a significant need for research activity. To ensure the proper exploitation of this energy resource, the decisive geophysical parameters of soil must be well-known. Within this study, thermal conductivity, as a fundamental property for evaluating the geothermal potential of very shallow geothermal systems, was analyzed and measured with a TK04 device. A dataset, consisting of various geophysical parameters (thermal conductivity, bulk density, water content, and porosity) determined for a large range of different textural soil classes, was collated. In a new approach, the geophysical properties were visualized covering the complete grain size range. The comparison between the measured and calculated thermal conductivity values enabled an investigation with respect to the validity of the different Kersten equations. In the course of this comparison, the influence of effective bulk density was taken into account. In conclusion, both Kersten formulas should be used as recommended and regular bulk density corresponded better to the reference dataset representing the outcomes of the TK04 laboratory measurement. Another objective was to visualize the relation of thermal conductivities within their corresponding textural classes and the validity of Kersten formulas for various bulk densities, depths, and soils. As a result, the accessibility to information for expedient recommendations about the feasibility of very shallow geothermal systems will be improved. Easy, accessible know-how of the fundamentals is important for a growing renewable energy sector where very shallow geothermal installations can also cover heating and cooling demands.
Keywords: soil properties; thermal conductivity; bulk density; textural soil classes; TK04 measurements

Comparison of ground temperature response of energy pile and borehole heat exchanger during thermal response tests - Luo, Jin; Zhao, Haifeng; Gui, Shuqiqang; Xiang, Wei; Rohn, Joachim (Environmental Earth Sciences, 2016)
Thermal migration of ground heat exchanger (GHE) in subsurface is crucially important to the efficiency and sustainability of ground source heat pump systems. In order to investigate heat transfer efficiency of GHE, ground temperature response during system operation should be analyzed. In this paper, two types of GHEs operate under heating operating condition are simulated by thermal response test. A set of parameters including fluid temperature, borehole wall and ground temperature are monitored with duration of 148 h. The analysis of thermal performance shows that the energy pile has specific thermal rates of 147 W/m which is 230% higher than that of borehole heat exchanger with 56 W/m. Furthermore, heat flux per unit area of the contacting area at borehole wall (q¯ , W/m2) is analyzed. The monitored temperature development at the borehole wall for both types of GHEs can be perfectly explained by q¯. The finding of this study indicates that the parameter is useful in estimating ground thermal accumulation of GHEs. The larger the q¯ is, the higher the possible of ground thermal accumulation and unstable performance of GHEs would be. © 2016, Springer-Verlag Berlin Heidelberg.
Keywords: Boreholes; Geothermal heat pumps; Heat exchangers; Heat flux; Heat pump systems; Heat transfer; Borehole heat exchangers; Energy piles; Ground heat exchangers; Ground temperature; Heat transfer efficiency; Temperature development; Thermal accumulation; Thermal response test; Piles

Comparison of Measured and Derived Thermal Conductivities in the Unsaturated Soil Zone of a Large-Scale Geothermal Collector System (LSC) - Rammler, Mario; Schwarz, Hans; Wagner, Jan; Bertermann, David (Energies, 2023)
The design, energetic performance, and thermal impact of large-scale geothermal collector systems (LSCs) are dependent on the thermal conductivity of unsaturated soils (λ). The aim of this study was to investigate the benefits of two different λ measurement methods using single-needle sensor measuring devices on a laboratory scale. Since large-scale determinations are required in the context of LSCs, the potential for deriving λ from electrical resistivity tomography measurements (ERTs) was also examined. Using two approaches—the continuous evaporation method and the punctual method—thermal conductivities of soil samples from Bad Nauheim (Germany) were measured. The results were compared with averaged λ derived from three ERT sections. With the evaporation method, significant bulk density changes were observed during the experimental procedure, which were caused by the clay content and the use of repacked samples. The punctual method ensures a sufficiently constant bulk density during the measurements, but only provides a small number of measurement points. The thermal conductivities derived from ERTs show largely minor deviations from the laboratory measurements on average. If further research confirms the results of this study, ERTs could provide a non-invasive and unelaborate thermal exploration of the subsurface in the context of large-scale infrastructure projects such as LSCs.<br
Keywords: large-scale geothermal collector system (LSC); thermal conductivity of soils; single-needle sensor; electrical resistivity tomography (ERT); shrinkage of soils; unsaturated soil zone

Comparison of organic and inorganic carbon isotope patterns across the Frasnian/Famennian boundary. - Joachimski, Michael (Palaeogeography, Palaeoclimatology, Palaeoecology, 1997)
The carbon isotopic composition of organic matter is reported for two Frasnian-Famennian boundary sections from the Rheinische Schiefergebirge (Germany). During the late Frasnian δ13C(org) values commonly range from -27.5‰ to -26‰. Highest δ13C(org) values around -24‰ are encountered immediately above and below the Kellwasser horizons. All samples from the Kellwasser horizons are depleted in δ13C(org) by -2.5‰ to -4.7‰. This depletion is explained by a higher proportion of biomass derived from isotopically depleted chemoautotrophic bacteria. A comparison of the positive δ13C excursions shows that the δ13C(org) shifts precede the 13C(carb) shifts by some 105 years. Consequently, Δδ13C values document a shift towards lower values below the Upper Kellwasser horizon. A contribution of terrestrial organic matter, as well as a thermal alteration of the δ13C(org) signals, do not provide compelling explanations for the earlier δ13C(org) shift. Increases in primary productivity or carbon burial rate will change the CO2(aq) content of surface waters, affect the carbon isotope fractionation during photosynthetic carbon uptake and thus enrich organic carbon in 13C. However, both processes cannot account for the earlier onset of the δ13C(org) shift, because the δ13C(carb) record should document the resulting 13C enrichment in surface waters as well. A reduction in the calcium carbonate precipitation rate, due to the global extinction of the reef ecosystem, may have played an important role in reducing the CO2(aq) content of surface waters without changing the isotopic composition of surface waters. Whether this process or other factors, such as a rise in sea-surface temperature or a change in the phytoplankton association, account for the earlier onset of the positive shift in the δ13C(org) curve must be determined by further studies that may be able to confirm the global significance of the reported δ13C(org) pattern in Frasnian-Famennian boundary sections from other parts of the globe.
UnivIS-Import:2015-03-05:Pub.1997.nat.dgeo.IGM.LG.compar
Keywords: Carbon; Frasnian-Famennian; Germany; Isotopes; Organic carbon; Rheinisches Schiefergebirge (Rhenish Slate Mountains); Upper Devonian

Comparison of physical and physicochemical methods for 3D printing application with the focus on the unconfined uniaxial compression test - Pott, Ursula; Jakob, Cordula; Wolf, Julian; Stephan, Dietmar (Construction and Building Materials, 2023)
For a commercial success of 3D concrete printing, standardisation is necessary to enable industrial production. To select methods for standardisation from the material side, detailed knowledge of suitable methods and of material behaviour is required in advance. Therefore, this study aims to compare different methods for investigating stiff printable mortars during the transition regime of a non-Newtonian fluid to a cohesive frictional material by physical and physicochemical methods focusing on the unconfined uniaxial compression test. The study shows that all methods exhibit comparable progressions, although the results are affected differently by self-heating, material composition and progressive hydration.
CRIS-Team Scopus Importer:2023-07-21
Keywords: Apparent static and dynamic Young's modulus; Early age mortar properties; Green strength; In-situ QXRD; Isothermal heat flow calorimetry; Slow penetrating sphere test; Ultrasonic wave transmission test

Comparison of precipitation collectors used in isotope hydrology - Michelsen, Nils; van Geldern, Robert; Roßmann, Y; Bauer, I; Schulz, S; Barth, Johannes; Schüth, Christoph (Chemical Geology (Isotopic Geoscience) Section, 2018)
Many hydrologic studies require data on the oxygen and hydrogen stable isotope composition (δ18O, δ precipitation and various collector designs have been suggested for gathering corresponding samples. Yet, crucial that these collectors, also known as totalizers, prevent evaporation and associated isotope fractionation. Surprisingly, we were unable to find a comprehensive collector intercomparison in the literature, and much one that addressed hot and arid conditions. In this study, we tested six different collector designs over a period of 32 days. They were filled to 20% total volume with water of known isotope composition and placed in a modified laboratory drying oven low relative humidity (5%) and a diurnal temperature change of 26 to 45 °C. Evaporative mass losses determined gravimetrically daily while samples for isotope analyses were collected every four days. The classic Oil collector, featuring a layer of paraffin oil to prevent evaporation, showed the smallest losses and no detectable isotope shift. The Tube-dip-in-water collector with pressure equilibration tube performed well, although we noted somewhat larger mass losses and isotope shifts. The latter accounted 0.28‰(Δδ18O) and 0.9‰(Δδ2 H) after 32 days, which is significant, but in view of the extreme conditions, changes should be still acceptable for most studies. The remaining collectors (Ball-in-funnel, Floating balls, Float based) all failed. Under the prevailing conditions, the Tube-dip-in-water collector with pressure equilibration tube seems represent a good, oil- and thus contamination-free compromise. Nonetheless, also in this system small cipitation amounts are problematic. This may necessitate modifications of the standard design in terms of diameter and bottle geometry. We strongly advise researchers to conduct own tests with their intended collector before field deploymen
Keywords: stable isotopes; rain water; sampler design

Comparison of whole wood and cellulose carbon and oxygen isotope series from Pinus nigra ssp. laricio (Corsica/France). - Szymczak, Sonja; Joachimski, Michael; Bräuning, Achim; Hetzer, Timo; Kuhlemann, Joachim (Dendrochronologia, 2011)
Stable isotopes in tree rings have widely been used for palaeoclimate reconstructions since tree rings record climatic information at annual resolution. However, various wood components or different parts of an annual tree-ring may differ in their isotopic compositions. Thus, sample preparation and subsequent laboratory analysis are crucial for the isotopic signal retained in the final tree-ring isotope series used for climate reconstruction and must therefore be considered for the interpretation of isotope–climate relationships. This study focuses on wood of Corsican Pine trees (Pinus nigra ssp. laricio) as this tree species allows to reconstruct the long-term climate evolution in the western Mediterranean. In a pilot study, we concentrated on methodological issues of sample preparation techniques in order to evaluate isotope records measured on pooled whole tree-ring cellulose and whole tree-ring bulk wood samples. We analysed 80-year long carbon and oxygen chronologies of Corsican Pine trees growing near the upper tree line on Corsica. Carbon and oxygen isotope records of whole tree-ring bulk wood and whole tree-ring cellulose from a pooled sample of 5 trees were correlated with the climate parameters monthly precipitation, temperature and the self-calibrating Palmer Drought Severity Index (sc-PDSI). Results show that the offsets in carbon and oxygen isotopes of bulk wood and cellulose are not constant over time. Both isotopes correlate with climate parameters from late winter and summer. The carbon and oxygen isotope ratios of cellulose are more sensitive to climatic variables than those of bulk wood. The results of this study imply that extraction of cellulose is a pre-requisite for the reconstruction of high-resolution climate records from stable isotope series of P. nigra ssp. laricio.
UnivIS-Import:2015-03-09:Pub.2011.nat.dgeo.IGM.LG.compar
Keywords: Pinus nigra ssp. laricio; Corsica

Compositional variation and 226Ra-230Th model ages of axial lavas from the southern Mid-Atlantic Ridge, 8°48′S - Haase, Karsten; Brandl, Philipp; Devey, Colin; Hauff, Folkmar; Melcher, Bernd; Garbe-Schönberg, Dieter; Kokfelt, Thomas; Paulick, Holger (Geochemistry Geophysics Geosystems, 2016)
We present geological observations and geochemical data for the youngest volcanic features on the slow spreading Mid-Atlantic Ridge at 8°48′S that shows seismic evidence for a thickened crust and excess magma formation. Young lava flows with high sonar reflectivity cover about 14 km in the axial rift and were probably erupted from two axial volcanic ridges each of about 3 km in length. Three different lava units occur along an about 11 km long portion of the ridge, and lavas from the northern axial volcanic ridge differ from those of the southern axial volcanic ridge and surrounding lava flows. Basalts from the axial rift flanks and from a pillow mound within the young flows are more incompatible element depleted than those from the young volcanic field. Lavas from this volcanic area have Ra-Th disequilibria model ages of 1000 and 4000 years whereas the older lavas from the rift flank and the pillow mound, but also some of the lava field, are older than 8000 years. Glasses from the northern and southern ends of the southern lava unit indicate up to 100°C cooler magma temperatures than in the center and increased assimilation of hydrothermally altered material. The compositional heterogeneity on a scale of 3 km suggests small magma batches rising vertically from the mantle to the surface without significant lateral flow and mixing. The observations on the 8°48′S lava field support the model of low-frequency eruptions from single ascending magma batches that has been developed for slow spreading ridges.
Keywords: basalt; mid-ocean ridge; volcanism

Compositional variation of mafic calc-alkaline lavas at the submarine Pausanias Volcanic Field, western South Aegean Volcanic Arc: Implications for magma formation and ascent - Wölki, Dominic; Beier, Christoph; Haase, Karsten; Günther, Thomas (Lithos, 2022)
The calc-alkaline lavas of the submarine Pausanias Volcanic Field and the neighboring Methana peninsula represent the largest volcanic edifices of the western South Aegean Volcanic Arc (SAVA) in the Mediterranean Sea and erupted on 30–35 km thick continental crust. We report the first whole rock major and trace elements together with Sr-Nd-Pb isotope ratios for basaltic to andesitic lavas from the submarine Pausanias Volcanic Field consisting of six smaller, volcanic structures. The mafic lavas have the most primitive compositions of the SAVA with MgO of up to 9 wt% and Ni concentrations >100 ppm. The incompatible trace element abundance patterns of the Pausanias and Methana lavas overlap and have typical island arc patterns, but Pausanias lavas display a larger geochemical heterogeneity on a smaller spatial scale compared to those from Methana. The Pausanias lavas resemble those from Methana in Sr, Nd, and Pb isotopes reflecting higher sediment subduction in the western SAVA than in the central arc at Santorini. The variability of incompatible element concentrations at relatively constant isotope compositions suggests variable degrees of partial melting of a peridotite-sediment mélange diapir in the mantle wedge. The Pausanias magmas formed from a less depleted mantle source compared to the central SAVA and their ascent in an extensional basin supported relatively rapid ascent without the extensive stagnation in the crust observed in the Methana magmas. The compositional differences between Pausanias and Methana imply differences in their composition and/or transport in the mantle wedge and the crust, allowing highly variable melts to reach the surface within a spatial distance of few kilometers.
CRIS-Team Scopus Importer:2022-07-01
Keywords: Aegean Arc; Mediterranean Sea; Olivine; Spinel; Submarine volcanism; Submarine volcano

Compositional zoning in dolomite from lawsonite-bearing eclogite (SW Tianshan, China): Evidence for prograde metamorphism during subduction of oceanic crust. - Li, Jilei; Klemd, Reiner; Gao, Jun; Meyer, Melanie (American Mineralogist, 2014)
Dolomite with compositional zoning was discovered in carbonate-lawsonite- bearing eclogites in the Tianshan (ultra-)high-pressure/low-temperature metamorphic belt, northwestern China. The eclogite-facies dolomite occurs as matrix porphyroblast and as inclusion in garnet, both of which display the same chemical zoning pattern. The dolomite contains inclusions of calcite (probably after aragonite), magnesite, glaucophane, lawsonite (and its pseudomorphs), allanite, epidote, paragonite, phengite, and omphacite. The chemical zoning in dolomite is well defined by a continuous core-to-rim Mg increase and Fe-Mn decrease. The concentrations of transition metal elements, REE, and Y also decrease from core to rim of the dolomite. Thermodynamic modeling demonstrates that the Fe-Mg zoning of dolomite is largely temperature dependent and, thus, is interpreted as prograde growth zoning, which developed during subduction of carbonate-bearing oceanic crust. It is suggested that dolomite in equilibrium with garnet formed as a result of changing matrix compositions due to increasing temperatures. In addition, thermodynamic modeling demonstrates that during subduction at high-pressure conditions prograde-formed aragonite and dolomite were transformed to dolomite and magnesite. Furthermore, Fe-rich magnesite inclusions in matrix dolomite and in dolomite inclusions in garnet are shown to have formed during high-pressure conditions prior to peak metamorphic conditions and, therefore caution is warranted using Fe-bearing magnesite occurrences in eclogite-facies rocks as an unambiguous ultrahigh pressure indicator as previously suggested. © 1997 - 2014 Mineralogical Society of America. All rights reserved.
UnivIS-Import:2015-03-09:Pub.2014.nat.dgeo.IGM.c3geoc.compos_1
Keywords: Dolomite; Eclogite; High pressure; Magnesite; Prograde zoning; Tianshan

Composition and distinction of white nephrite from Asian deposits - Schmädicke, Esther; et al. (Neues Jahrbuch für Mineralogie-Abhandlungen, 2013)
Keywords: Asian nephrite deposits; Archaeology; Tremolite; Electron microprobe analysis; White nephrite

CONCH - ammonoid morphometric software - Hoffmann, René; Weinkauf, Manuel; Wiedenroth, Kurt; Goeddertz, Peter; de Baets, Kenneth (2019)
Morphological analyses of ammonites are a time-consuming process. The software CONCH allows to gather the established sets of morphological characteristics (i.e., diameter, whorl height, whorl interspace, umbilical width) as well as the traditionally derived parameters and three different rib density parameters in steps of 10, 30 or 45 radial degrees. Data can be exported as .csv files, images of the ammonites with set landmarks can be saved, and projects can be stored for later continuation. The software thus streamlines ammonite analyses and allows scientists to converge on a single software to perform all ammonite morphological analyses for enhanced compatibility in the futur

Concluding IGCP 503: Towards a holistic view of Ordovician and Silurian earth systems - Harper, David A.T.; Li, Jun; Munnecke, Axel; Owen, Alan W.; Servais, Thomas; Sheehan, Peter M. (EPISODES, 2011)
IGCP 503 'Ordovician Palaeogeography and Palaeoclimaté was established in 2004 primarily to identify the main drivers, both biological and geological, of the Great Ordovician Biodiversification Event. From the outset of the project it was clear that this event was part of a larger-scale, long-term, multifaceted process that included the end Ordovician extinction and Silurian recovery, if not more. IGCP 503 thus developed a major network that included scientists whose interests spanned the entire Lower Palaeozoic and encompassed a range of disciplines from classical palaeontology and palaeoecology through isotope geochemistry to climate modellin
Keywords: Ordovician; palaeogeography; palaeoclimate; GOBE; great ordovician biodiversification event; IGCP; Silurian recovery; Ordovician event; lower palaeozoic

Concurrent kinetics of crystallization and toughening in multicomponent biomedical SiO2-Li2O-P2O5-ZrO2 glass-ceramics - Lubauer, Julia; Belli, Renan; Petschelt, Anselm; Cicconi, Maria Rita; Hurle, Katrin; Lohbauer, Ulrich (Journal of Non-Crystalline Solids, 2021)
We investigate here the crystallization kinetics of two pre-crystallized multicomponent dental glass-ceramics (IPS e.max® CAD, Ivoclar-Vivadent; Suprinity® PC, Vita Zahnfabrik) by interrupting the heat treatment at different periods of the non-isothermal and isothermal stage at 840°C. Differential scanning calorimetry (DSC) was used to characterize the crystallization peaks of the pre-crystallized and the base glass, and dilatometry was used to determine the coefficient of thermal expansion and Tg after different times at the maximum temperature. The evolution of crystallinity was tracked by XRD, while the evolution of fracture toughness was obtained by the ball-on-three-balls surface crack in flexure method. The change in microstructural features was made visible using FE-SEM. We show that the isothermal stage is dominated by the transformation of Li2SiO3 in Li2Si2O5, inducing the impingement of nanocrystals into clusters. The residual glass became thereby less polymerized. The kinetics of toughening followed closely the evolution of crystallinity in both systems.
CRIS-Team Scopus Importer:2021-02-12

Conditions of melting beneath the Azores - Beier, Christoph; Haase, Karsten; Turner, Simon P. (Lithos, 2012)
The depth and temperatures of melting beneath Ocean Islands provide important constraints on mantle melting dynamics. The central Azores islands of Faial, Pico, Graciosa and São Jorge are ideally suited for calculating depth and temperatures of melting because they are situated orthogonal to the slow spreading Mid-Atlantic Ridge and thus supposedly on variable lithosphere thicknesses which allow to constrain on the influence of lithosphere thickness on average melting depth. The dataset presented here is used to test the spatial pattern of potential temperature anomalies in the Azores mantle plume. Trace elements indicate comparable degrees of partial melting for all three islands, while Sr-Nd-Pb isotope ratios and incompatible trace element ratios imply only small-scale source heterogeneity that is not related to the major element systematics. Thus, the observed differences in calculated, primary SiO , FeO and TiO (and Al O ) are inferred to reflect changes in melting pressures and temperatures that are independent of source composition. Melting temperatures in the Azores are lower and melting starts deeper than at other mantle plumes (e.g., Hawaii). This implies that the smaller size of the Azores compared to other mantle plumes might be the result of a much smaller anomaly with a large variability of depths and temperatures of melting even on the scale of an individual island. This small-scale variability is of importance when comparing pressures and temperatures between different islands or even globally. The Azores lavas have temperatures lower than predicted for a dry mantle solidus indicating the presence of at least 200ppm H O in the Azores mantle source. © 2012 Elsevier B.V.
Keywords: Azores; Geodynamics; Major elements; Ocean Island Basalts; P-T estimates

Cone morphologies associated with shallow marine eruptions: East Pico Island, Azores - Mitchell, Neil C.; Stretch, Rachelle; Oppenheimer, Clive; Kay, Daniel; Beier, Christoph (Bulletin of Volcanology, 2012)
Eruptions in shallow water typically produce cones of volcaniclastic material. In order to identify any systematic effects of water depth and other environmental parameters on cone morphology, we have measured the heights and widths of cones in multibeam echo-sounder data from a submarine ridge extending southeast from Pico Island, Azores. XRF analyses of dredged samples show that lavas here vary compositionally from alkali basalt to trachybasalt and trachyandesite. Cones in deeper water are generally steep-sided with upper flanks close to 30°, the dip of talus at the angle of repose. However, height/width ratios of cones vary more in shallow water (200-400-m summit depth) with extreme values below 0. 1; while some shallow-water cones are steep-sided as in deep water, others are much flatter. Three such cones lie on a bench at 300-m depth immediately east of Pico Island and have flank slopes of only 10-20°. We speculate that exceptionally shallow cone slopes here were produced by forced spreading of the erupting columns on reaching the water-air density barrier. © 2012 Springer-Verlag Berlin Heidelberg.
Keywords: Cone morphologies; Pico Island; Shallow marine eruptions; Volcaniclastic material

Conodont and carbon isotope stratigraphy near the Frasnian/Famennian (Devonian) boundary at Wulankeshun, Junggar Basin, NW China - Wang, Z. H.; Becker, R. T.; Aboussalam, Z. S.; Hartenfels, S.; Joachimski, Michael; Gong, Y. M. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2016)
Conodont faunas from the Wulankeshun section in the northwestern Junggar Basin of Xinjiang, NW China, are characterized by shallow-water assemblages with many endemic taxa. This study presents separate local icriodid and polygnathid conodont zonations for the Lower Member of the Hongguleleng Formation, which can only roughly be correlated with the pelagic "standard zonation". The basal beds of the Hongguleleng Formation are assigned to a low diverse Icriodus praealternatus ferus n. ssp. Zone, which possibly includes latest Frasnian strata but it continues into the basal Famennian. At present, the Frasnian/Famennian boundary cannot be defined unequivocally by conodonts and there are no obvious Upper Kellwasser equivalents. However, the carbon isotope data are comparable with the Bulongguor Reservoir stratotype, where the top-Frasnian lies within the basal Hongguleleng Formation. In the early Famennian, partly endemic icriodid lineages provide successive Icriodus cornutus, I. stenoancylus junggarensis n. ssp., and I. plurinodosus n. sp. (sub)zones. The basal Famennian is possibly marked by the oldest, endemic species of Neopolygnathus, Neo. huijunae n. sp. It is followed by local Neo. communis communis, "Polygnathus" pomeranicus, Po. cf. szulczewskii, and "Po." pseudocommunis n. sp. zones. The new local conodont zonations provide a high biostratigraphic resolution for further future studies. The Wulankeshun shallow-water conodont faunas show restricted similarities with contemporaneous faunas from eastern Europe, Kazakhstan, and Iran. There are a few taxa that were originally described from other distant regions, such as NW Canada and eastern Australia. The local high number of endemic taxa (17 (sub)species, 46%) points to a significant plate tectonic isolation of the Junggar Basin in the early Famennian.
Keywords: Carbon isotopes; Conodonts; Frasnian/Famennian; Junggar Basin; Late Devonian

Conodont apatite oxygen isotope record of the Permian: ice volume and palaeotemperature evolution - Chen, Bo; Joachimski, Michael; Shen, Shu-Zhong; Lambert, Lance L.; Lai, Xu-Long; Wang, Xiang-Dong; Chen, Jun; Yuan, Dong-Xun (Gondwana Research, 2013)
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.conodo_6

Conodont apatite δ18O signatures indicate climatic cooling as a trigger of the Late Devonian mass extinction - Buggisch, Werner; Joachimski, Michael (Geology, 2002)
UnivIS-Import:2015-03-09:Pub.2002.nat.dgeo.IGM.LG.conodo
Keywords: 18O/16O; Apatite; Late Devonian; Mass extinction; Paleotemperature

Conodont apatite δ18O signatures indicate climatic cooling as a trigger of the Late Devonian mass extinction: Reply - Joachimski, Michael; Buggisch, Werner (Geology, 2003)

Conodont biostratigraphy and carbon isotope stratigraphy of the middle Ordovician (Darriwilian) Komstad Limestone Formation, southern Sweden - Wu, Rongchang; Calner, Mikael; Lehnert, Oliver; Lindskog, Anders; Erlström, Mikael; Joachimski, Michael (GFF, 2018)

Conodont biostratigraphy and carbon isotope stratigraphy of the Middle Ordovician (Darriwilian) Komstad Limestone, southern Sweden - Wu, Rong Chang; Calner, Mikael; Lehnert, Oliver; Lindskog, Anders; Joachimski, Michael (GFF, 2018)
Keywords: carbon isotope stratigraphy; conodont biostratigraphy; Darriwilian; Komstad Limestone; Middle Ordovician; Sweden

Conodont biostratigraphy and palaeoenvironmental trends during the Famennian (Late Devonian) in the thuringian buschteich section (Germany) - Girard, C.; Cornée, J. J.; Charruault, A. L.; Corradini, C.; Weyer, D.; Bartzsch, K.; Joachimski, Michael; Feist, R. (Newsletters on Stratigraphy, 2017)
This study characterizes the stratigraphical context as well as the palaeoenvironmental and sealevel trends during the Late Frasnian and Famennian in the Buschteich section (Thuringia, Germany). An integrated approach combines conodont biostratigraphy, chemostratigraphy based on carbon and oxygen isotopes, conodont biofacies analyses and investigations of the morphotypes of foraminifera that occur in the section was applied. Conodonts provided a fine-scale biostratigraphical framework. All the Famennian conodont biozones were identified, with the exception of the three lowest. The Frasnian-Famennian transition was further identified by a positive carbon isotope excursion. This continuous Famennian record is developed in a condensed limestone succession. The reddish Griotte facies, typical of strata of this period, were not documented. Black shales were not developed except for an interval of dark colored mud rocks corresponding to the Hangenberg event at the top of the section. The carbonate succession of Buschteich was deposited in an outer ramp environment, pelagic organisms are the dominant fauna. This is corroborated by the overall dominance of the deep-water conodont genus Palmatolepis. Microfacies, conodont biofacies and foramini - fera indicated a deepening trend from the Lower crepida to the Lower rhomboidea Zone, followed by a shallowing trend from the Upper rhomboidea to the praesulcata Zone. This sequence overall matches the sea level reference curve for Euramerica. The timing of maximum water depth at Buschteich, as well as the general sea-level reference record, differs from the Col des Tribes (Montagne Noire, France). Differential uplift or overprinting of the long-term eustatic changes may be the cause of the discrepancy in the local sea-level records.
Keywords: Conodonts; Depositional environment; Microfacies; Saxo-thuringian; Sea level; Upper devonian

Conodont biostratigraphy in the Early to Middle Ordovician strata of the Oslobreen Group in Ny Friesland, Svalbard - Lehnert, Oliver; Stouge, Svend; Brandl, Philipp (Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 2013)
The remotely located Cambro-Ordovician strata in Ny Friesland, NE Spitsbergen, Svalbard, are referred to the Oslobreen Group, which is composed of the Tokammane, Kirtonryggen and Valhallfonna formations. Herein we record the conodont succession of the Kirtonryggen and Valhallfonna formations. Collections of well-preserved conodonts (CAI 1) have been recovered from the Lower to lower Middle Ordovician interval in the region. Eight regional conodont zones are established in this preliminary study of the Oslobreen Group exposed at Hinlopenstretet, NE Svalbard. In ascending order these zones are: Rossodus manitouensis, Macerodus dianae, Oneotodus costatus, Oepikodus communis, O. evae, O. inter-medius, Periodon aff. flabellum-Periodon hankensis and Periodon macrodentatus. The yield is relatively poor for the Kirtonryggen Formation, but the oldest Ordovician conodont faunas span the Trema-docian Rossodus manitouesis through Macerodus dianae zones followed by the Floian Oepikodus communis Zone. The taxa are typical of the tropical North American Midcontinent faunal province that dominated the region until open marine associations invaded the shallow shelf (i.e. Evae transgression). The pandemic Oepikodus evae becomes frequent and is succeeded by O. intermedius in abundance in the lower Valhallfonna Formation (Olenidsletta Member). The upper strata are characterised by the Periodon-Paroistodus assemblage characteristic for outer shelf and slope environments around Laurentia. In total, this formation comprises the Floian and Dapingian stages and ends in the early Darriwilian Periodon macroden-tatus Zone in this region. The Ny Friesland faunas show affinities to coeval assemblages from Northeast Greenland and West Newfoundland. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
UnivIS-Import:2015-03-09:Pub.2013.nat.dgeo.IGM.LG.conodo
Keywords: Conodont biostratigraphy; Ny Friesland; Ordovician; Svalbard (Spitsbergen); Tremadocian