Projects
Project P-34238 - The evolution of the earliest marine habitats on Earth (2021 - 2024)
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:
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.
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.