11 Works

Thermo-compositional models of the West Gondwana cratons

Nils-Peter Finger , Mikhail K. Kaban , Magdala Tesauro , Walter D. Mooney & Maik Thomas
When Western Gondwana broke apart into the South American and African continents ca.120 Ma ago, some of its cratons were broken apart as well. Following the isopycnic hypothesis, their long-term stability and often neutral to positive buoyancy can be explained by the counteracting effects of cooling (density increase) and iron depletion (density decrease). To separate these effects, we created the presented models following an iterative integrated approach using mainly seismic and gravity data. In the...

Recent headwall deglaciation and retreat from cosmogenic 10Be in medial moraine debris of a Swiss valley glacier

Katharina Wetterauer, Dirk Scherler , Leif S. Anderson & Hella Wittmann
Debris-covered glaciers are fed from steep bedrock hillslopes that tower above the ice, so-called headwalls. Recent observations in high-alpine glacial environments suggest that rock walls are increasingly destabilized due to climate warming. An increase in debris delivery to glacier surfaces will modify glacial mass balances, as surface debris cover impacts on the melt behavior of the ice underneath. Consequently, we expect that the response of debris-covered glaciers to climate change is likely linked to how...

Tectonic accretion controls erosional cyclicity in the Himalaya

Dirk Scherler , Sanjay Kumar Mandal & Hella Wittmann
Indian Institute of Science Education and Research Kolkata, Mohanpur, India(3);The evolution of Earth’s climate over geological timescales is linked to surface erosion by weathering of silicate minerals and burial of organic carbon. However, methodological difficulties in reconstructing erosion rates through time and feedbacks among tectonics, climate, and erosion spurred an ongoing debate on mountain erosion sensitivity to tectonic and climate forcing. A key question is whether late Cenozoic climate cooling has increased global erosion rates...

Millennial variability, hydrological and limnological changes during MIS3-2 in Lake Petén Itzá, Guatemala

Rodrigo Martinez-Abarca, Michelle Abstein , Philipp Hoelzmann , Thorsten Bauersachs , Liseth Pérez , Mona Stockhecke , Sergio Cohuo Duran & Antje Schwalb
Heinrich Stadials and Greenland Interstadials are abrupt climate variations that are observed in the Northern Hemisphere throughout Marine Isotopic Stages (MIS) 3-2. Lake Petén Itzá, northern Guatemala, is a key site for paleoclimate investigations due to its sensitivity to changes in climate forcing such as the Intertropical Convergence Zone (ITCZ) and the Atlantic Meridional Overturning Circulation (AMOC). In this study, we reconstructed the hydrology and limnology of Lake Petén Itzá during MIS3-2 based on geochemical...

In-situ silicon isotopes in mantle wedge serpentinites - a new proxy for slab dehydration reactions

Sonja Geilert , Elmar Albers , Daniel A. Frick , Christian T. Hansen & Friedhelm von Blanckenburg
The Mariana forearc provides a unique natural laboratory to study slab dehydration in an active subduction zone by its deep-rooted mud volcanism. To test if mantle wedge serpentinites would record the source fluid composition and thus the dehydration reactions in the slab, we investigated silicon (Si) isotopic compositions (δ30Si) in serpentine veins by in-situ femtosecond laser ablation ICP mass spectrometry. Our samples were recovered during IODP Expedition 366 and originate from three mud volcanoes that...

Redox conditions during deserpentinization in western Elba Island, Italy.

Malte Kalter & Wolfgang Bach
The observation of oxidized arc melts has led to a discussion about the redox conditions during the dehydration reactions of serpentinites in subduction zones. The discussed range of oxygen fugacities (fO2) between+5 and -2 log units relatively to the QFM buffer allows sulfur to be present either as oxidized or reduced species. This work investigates the development of the fO2 with serpentines form the western part of the island Elba in Italy. We compared observations...

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...

Comparison of high-resolution SIMS profiles with maximum resolution IRMS stable isotope data

Tobias Kluge , Philipp Holz , Elisabeth Eiche , Thomas Neumann , Alexander Land , Maximilian Schuh , Mario Trieloff & Axel K. Schmitt
High-resolution speleothem paleoclimate records with annual to seasonal resolution are helpful for detailed analysis of climatic changes with limited duration (e.g., volcanic climate impacts), but also for longer-duration events (e.g., at 8.2 ka or 4.2 ka). A high resolution paleoclimate data set is also mandatory for meaningful comparison with archaeological or historical records. Low stalagmite growth rates could impede the acquisition of high-resolution isotope data with the classical micro-milling approach and isotope ratio mass spectrometry...

Revised and improved geological model of the Waiwera geothermal reservoir, New Zealand

Andreas Grafe , Thomas Kempka , Michael Schneider & Michael Kühn
Following a thermal and photogrammetric outcrop mapping campaign undertaken at the Waiwera geothermal reservoir in 2019, a pre-existing 3D hydrogeological model was revised in the present study to assess the impact of the updated structural and lithological interpretation on the existing numerical model calibration. For the latter, well data comprising measured temperature and salinity profiles were employed to reconstruct the reservoir’s natural thermal state and spatial distribution of salinity, supported by numerical simulations of density-driven...

A global rate of denudation from cosmogenic nuclides in the Earth’s largest rivers

Hella Wittmann , Marcus Oelze , Jerome Gaillardet , Eduardo Garzanti & Friedhelm von Blanckenburg
Cosmogenic nuclide analysis in sediment from the Earth’s largest rivers yields mean denudation rates of the sediment-producing areas that average out local variations commonly found in small rivers. Using this approach, we measured in situ cosmogenic 26Al and 10Be in sand of >50 large rivers over a range of climatic and tectonic regimes covering 32% of the Earth’s terrestrial surface. In 35% of the analyzed rivers, 26Al/10Be ratios are significantly lower than these nuclides´ surface-production-rate...

LI@Geo.X – A Laboratory Infrastructure Search Portal for the Geo.X Network

Manja Luzi-Helbing , Christopher Hamann , Kirsten Elger , Damian Ulbricht , Florian Ott , Marc Hanisch , Nils Brinckmann , Hannes Fuchs , Hildegard Gödde , Roland Bertelmann & Lutz Hecht
Geo.X is the research network for geosciences in the Berlin and Potsdam metropolitan region and integrates five universities and six extramural research institutions. Our partners are committed to a FAIR and sustainable handling of research data and infrastructures. For this purpose, we established a search portal for the geoscientific laboratory infrastructure and related research data of the network partners (LI@Geo.X). The portal aims to increase the visibility and accessibility of the partner institutions’ infrastructures, data,...

Registration Year

  • 2022
    11

Resource Types

  • Text
    11

Affiliations

  • Freie Universität Berlin
    10
  • Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
    8
  • University of Bremen
    2
  • Institut de physique du globe de Paris
    1
  • University of Hohenheim
    1
  • Tecnológico Nacional de México, Mexico
    1
  • Indian Institute of Science Education and Research Kolkata
    1
  • TU-Braunschweig, Braunschweig, Germany
    1
  • University of Lausanne
    1
  • University of Minnesota-Duluth, USA
    1