10 Works

Magnesium and calcium isotope fractionation during microbial dolomite formation

Michael Tatzel , Adina Paytan , Samantha Carter , Daniel A. Frick , Francisca Martinez-Ruiz , Zach A. DiLoreto , Maria Dittrich , Tomaso R. R. Bontognali & Mónica Sanchez-Román
Microbial mediation is considered an important process for the formation of primary dolomite at ambient temperature. Yet, no structural, mineralogical, chemical or isotopic means exist to discern this mode of dolomite formation from secondary dolomite. To explore the utility of metal isotopes in allowing this distinction we characterize magnesium and calcium stable isotope ratios in primary (proto)dolomites from a modern hypersaline environment. Samples from the Khor Al-Adaid sabkhas in Qatar show consistent isotopic differences of...

Large regional structures from puzzle pieces - the hidden Triassic rift on the western flank of the Eichsfeld-Altmark-Swell

Alexander Malz, Jonas Kley & Heinz-Gerd Röhling
The incorporation of regional geologic knowledge is essential to solve multiple geological questions in any defined research area meaning that small-scale observations must fit with general regional interpretations as well as the tectonic and sedimentary setting. Conversely, in areas with sparse subsurface information, a conceptional knowledge of the observed area must be developed by incorporating and combining small-scale indications into a sound regional geologic model. In this contribution, we collect some of these small-scale “puzzle...

Habitability of early Earth: Liquid water under a faint young Sun facilitated by tidal heating due to a closer Moon

René Heller , Jan-Peter Duda , Max Winkler , Joachim Reitner & Laurent Gizon
Carbonatites crystallize from mantle-derived carbonate- and volatile-rich melts that exsolve large amounts of fluids during their ascent through and emplacement into the crust. A global review of available fluid inclusion data for carbonatitic systems from variable emplacement depths identified four types of fluid inclusions: (type-I) vapour-poor H2O-NaCl fluids with <50 wt.% salinity; (type-II) vapour-rich H2O-NaCl-CO2 fluids with <5 wt.% salinity; (type-III) multi-component fluids with high salinity without CO2; and (type-IV) multi-component fluids with high salinity...

OneGeochemistry: Enabling a coordinated online global network of multiple distributed geochemical repositories and databases

Kerstin Annette Lehnert , Lesley Wyborn , Dominik Hezel , Alexander Prent , Kirsten Elger , Geertje ter Maat , Marthe Klöcking & Jens Klump
Since the discipline of ‘geochemistry’ was first defined in 1838, geochemical data has been pervasively acquired and used in the Earth, environmental and planetary sciences and become fundamental for understanding past, present, and future processes in natural systems. Initially, geochemical data was published in hard-copy literature, but as analytical systems became computerised, major digital databases emerged (EarthChem, PetDB, OZCHEM and GEOROC) which revolutionised data access. They have proven the power of re-use of geochemical data...

Combined architectural-element and microfacies analyses in carbonate sedimentology: the intra-basin shoal complex of the Lower Muschelkalk (Rüdersdorf Formation, Anisian)

Fabian Käsbohrer & Matthias Franz
The layer-cake strata of the epeiric Anisian-Ladinian Muschelkalk are devoid of large-scale architectural elements, e. g. steep clinoforms of a progradional platform slope. This resulted in a simplified approach in facies analysis, in which results of classical microfacies analysis (microscale) are used directly to conclude on depositional models (macroscale). In coastal settings, depositional cycles (mesoscale) are often defined in an intermediate step to visualize progradational or retrogradational patterns of shorelines or shoreline-detached shoals. Apart from...

Exhumation and erosion rates in the flat-topped Nock Mountains in the Eastern Alps constrained by low-temperature and cosmogenic 10Be data

Andreas Wölfler , Andrea Hampel , Christoph Glotzbach & István Dunkl
Constraining rates of landscape evolution is a necessary pre-requisite for reconstructing the spatiotemporal evolution of the Earth´s surface. In our study, we present new zircon and apatite fission track and (U-Th)/He ages as well as catchment-wide 10Be-derived erosion rates to determine exhumation and erosion rates in the Nock Mountains, an elevated-low relief landscape in the Eastern Alps. Zircon fission track and zircon (U-Th)/He analyses yielded cooling ages of ~90 and ~80 Ma, respectively, which we...

Does regional geology help to assess earthquake hazard in continental interiors?

Tim Hahn, Jonas Kley, Diethelm Kaiser & Thomas Spies
Earthquake hazard assessment is crucial for different planning tasks, including the search for a German nuclear waste repository. Germany is located in an intraplate setting with a low level of seismicity and the seismically active faults are incompletely known. To solve this problem, seismotectonic regions (SR) of assumed uniform seismicity can be defined and used as a basis to define seismic area sources to be used in seismic hazard analyses. We have elaborated a new...

Late Anisian microbe-metazoan build-ups (“stromatolites”) in the Germanic Basin – aftermath of the Permian – Triassic Crisis

Yu Pei , Jan-Peter Duda , Jan Schönig , Cui Luo & Joachim Reitner
The so-called Permian – Triassic mass extinction was followed by a prolonged period of ecological recovery that lasted until the Middle Triassic. Triassic stromatolites from the Germanic Basin seem to be an important part of the puzzle, but have barely been investigated so far. Here we analyzed late Anisian (upper Middle Muschelkalk) stromatolites from across the Germanic Basin by combining petrographic approaches (optical microscopy, micro X-ray fluorescence, Raman imaging) and geochemical analyses (sedimentary hydrocarbons, stable...

Automated heavy mineral analysis of silt-sized sediment by artificial-intelligence guided Raman Spectroscopy

Nils Keno Lünsdorf , Jan Ontje Lünsdorf , Gábor Újvári & Hilmar von Eynatten
Compositional data on heavy minerals is fundamental in sedimentary provenance analysis. Typically, this data is gathered by optical microscopy and more recently, by mineral chemical analysis (MLA, QEMSCAN) or Raman micro-spectroscopy. In silt-sized sediments optical microscopy is unfeasible. We introduce a systematic and highly efficient approach to assess the heavy mineral composition in fine grain-size fractions (10-30 µm and 30-62 µm) by Raman micro-spectroscopy. The approach starts with a web-application that creates and visualizes large...

Si isotope thermometry in silicified carbonate

Michael Tatzel , Marcus Oelze , Moritz Liesegang , Maria Stuff & Michael Wiedenbeck
Cherts, including silicified carbonates, are one of the most detailed and alteration resistant archives of near-surface environments. Yet, the information disclosed in form of stable isotope ratios of Si and O cannot be confidently translated into conditions prevailing at the Earth surface in deep time. Thermometry based on δ18O is compromised by the lack of knowledge about the fluid’s δ18O value and attempts to determine Si sources or temperatures from δ30Si remain unsatisfying. We investigated...

Registration Year

  • 2022
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Resource Types

  • Text
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Affiliations

  • University of Göttingen
    9
  • University of Tübingen
    3
  • Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
    3
  • Göttingen Academy of Sciences and Humanities
    2
  • VU Amsterdam
    1
  • Columbia University
    1
  • University of Münster
    1
  • Nanjing Institute of Geology and Paleontology
    1
  • Australian National University
    1
  • Institute for Geological and Geochemical Research
    1