SPP 1006 - Subproject: Resolving sedimentary sulphur cycling during the Shunga Event (early Paleoproterozoic) with sulphur isotopes

Basic data for this project

Description

Organic- and sulphide-rich sediments of the ca. 2000 million year old Zaonezhkaya Formation have archived one of the major global perturbations of Earth's surface environments in the early Paleoproterozoic: the deposition of an unprecedented amount of organic matter (termed the Shunga Event). Much if not all of the subsequent mineralization of this sedimentary organic matter was achieved via microbially mediated (largely anaerobic) pathways. Sulphur isotopic evidence suggests that microbial sulphur cycling, and most prominently bacterial sulphate reduction appears to be of prime importance but that it occurred under highly variable conditions. Resulting sedimentary sulphides display a wide textural spectrum, underlining the temporal and spatial variability of respective boundary conditions in the diagenetic realm. A full understanding of the Shunga event requires a firm assessment of its depositional and diagenetic history. This will be achieved through the integration of petrographic, geochemical, and stable isotopic data. A two-fold analytical approach will combine detailed temporal records and data obtained at high spatial resolution. It is the ultimate goal to unravel the history of these sediments in the context of global perturbations across the Archean-Proterozoic transition.