SPP 1006 - Subproject: Peering into the Cradle of Life: multiple sulphur isotopes reveal insights into environmental conditions and early sulphur metabolism some 3.5 Ga ago (2nd funding period)

Basic data for this project

Description

Environmental conditions under which life emerged on Earth were much different from today. Unravelling respective boundary conditions and searching for signs of early life is limited to a few well preserved rock units with an age of 3500 Ma. One of the key localities is the Barberton Greenstone Belt in southern Africa where rocks contain clear traces of life: microscopic structures composed of carbonaceous material and interpreted as microfossils, stromatolites, and geochemical and isotopic evidence that document the early presence of a rich microbial ecosystem on Earth. Microbial sulphur cycling appears to be among the most ancient metabolic processes prevailing in these communities, based on evidence from molecular biology and (isotope) geochemistry. Multiple sulphur isotopes have proven to be an environmental proxy as much as a biosignature, in particular in deep time research. Mass-independent sulphur isotope fractionation allows constraining important environmental parameters such as the composition of Earth’s atmosphere and the availability of sulphate in the early ocean. In concert with mass-dependent sulphur isotope fractionation, some of the key metabolic pathways on the early Earth have been identified. Consequently, multiple sulphur isotopes and complementary geochemical analyses will be used in order to peer into the cradle of life.