Projects
The evolution of the earliest marine habitats on Earth (2021 - today)
Summary:
This project aims to reconstruct marine environments and the geodynamical evolution of continental landmasses in the time frame between 2.9 and 3.5 billion years ago. The results provide fundamental insights into how landmasses and marine environments evolved through the Archean and improve our current understanding from the interplay of weathering and erosion processes of emerged landmasses with marine environments on Early Earth.
In particular, the results provide unique information on the evolution of local and global Archean seawater chemistry, the atmos- and hydrosphere systems, as well as the sources of elements affecting Archean seawater. Additionally, Hf-Nd isotope compositions determine the impact of elemental fluxes from emerged continents into Archean marine environments. For the first time, this project traces the Hf-Nd isotope record of oceans from 2.7 billion years back until ~3.5 billion years ago and establishes Hf-Nd isotopes in marine chemical sediments as novel geochemical proxy for weathering and erosion processes on Precambrian continents. In particular, the results pinpoint the time in Earth's history when landmasses were - for the first time - emerged and significantly affected seawater chemistry via chemical weathering.
The project was funded by the Austrian Science Foundation FWF-Der Wissenschaftsfonds under grant number P-34238.
related publications:
Krayer J., Jodder J., Hofmann A., Weyer S., Willbold M., Schulz T., Koeberl C., Viehmann S., 2025. The influence of mafic and felsic crust on the seawater chemistry ca. 3.0 billion years ago: Evidence from Nd isotopes in banded iron formations from the Murchison Greenstone Belt. Precambrian Research 418, 107701.
Wainwright A.N., Debaille V., Hoffmann J.E., Viehmann S., Bau M. 2024. Neoarchean marine chemical sediments as archives of Hadean silicate differentiation. Geochemical Perspective Letters v30
Mundl-Petermeier A.*, Viehmann S.*, Tusch J., Bau M., Kurzweil F., Münker C., 2022: Earth's geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13:2701.
Bau M., Frei R., Garbe-Schönberg D., Viehmann S., 2022: High-resolution Ge-Si-Fe, Cr isotopes and Th/U data for the Neoarchean Temagami BIF, Canada, suggest primary origin of BIF bands and oxidative terrestrial weathering 2.7 Ga ago. Earth and Planetary Science Letters 589, 117579.
Fractionation of stable antimony isotopes as fingerprinting tool to determine sources and distribution of contamination (2024 - today)
Summary:
Antimony (Sb) is a toxic element that primarily occurs in sulfur-rich ore bodies, and its uptake into the human body over extended periods can lead to cancer, disturbances in the optical nerves (e.g., uveitis, retinal hemorrhages), and heart disease. In recent years, Sb isotope ratios have been used as a geochemical environmental tracer due to Sb's high redox sensitivity, to trace contamination pathways from spoil heaps into soils and waters, and to better control human health impacts. Additionally, it has recently been shown that Sb isotopes in Sb-rich minerals can serve as an exploration tool, providing clues about the formation of undiscovered Au, Ag, and Cu-Sb deposits underground.
In the proposed project, Sb isotope ratios will be used to(I) determine the environmental impact of Sb (and other toxic elements in sulfides such as As) on soils, waters, and drinking water near mines, thereby assessing the direct impact on humans. (II) Furthermore, Ag- and Au-rich mines such as the Rammelsberg, St. Lorenz, or Agezucht mines in the Harz region will be used as case studies to apply Sb isotopy as an exploration tool in Sb minerals to potentially locate additional undiscovered ore bodies underground.
The project is a granting project ("Vergabeprojekt)" by the Federal Institute for Geosciences and Natural Resources (BGR) under project number P-204-4500139869.
related publications:
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Project ELEMIN - How the earliest life on Earth became mineralised (2017 - 2019)
Summary
Project ELEMIN targets geochemical and petrographic investigations of Proterozoic and Archean stromatolites, i.e. lithified microbial mats, to (I) determine the genesis of mineral phases preserved within the stromatolites and (II) reconstruct physico-chemical environmental conditions prevailing in microbial habitats. The timing and conditions of individual mineral phases in stromatolites is under debate and, thus, their reliability as geochemical archives is highly uncertain. One controversy is centered on the question of whether different mineral phases record the elemental composition of the seawater in which the stromatolites grew, was mainly derived from continental weathering or from submarine hydrothermal sources.
This project was funded by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie action [grant no. 746033].
related Publications:
Viehmann S., et al.., 2020: Carbonates and cherts as archives of seawater chemistry and habitability on a carbonate platform 3.35 Ga ago: Insights from Sm/Nd dating and trace element analysis from the Strelley Pool Formation, Western Australia. Precambrian Research 344, 105742.
Viehmann S. et al. 2019:
Kraemer D. et al. 2019: Regional variations in fluid formation and metal sources in MVT mineralization in the Pennine Orefield, UK: Implications from rare earth element and yttrium distribution, Sr-Nd isotopes and fluid inclusion compositions of hydrothermal vein fluorites. Ore Geol. Rev. 107, 960-972.
Viehmann S., 2018: Hf-Nd Isotopes in Archean Marine Chemical Sediments: Implications for the Geodynamical History of Early Earth and Its Impact on Earliest Marine Habitats. Geosciences 8 (7), 263, 1-15.