• Chemical changes in the late Precambrian surface system

The latet Neoproterozoic to Cambrian time marks the appearance of the animals and major changes in the oxygen content of the atmosphere-ocean system. In the context of the DFG research group “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents” (FOR 736), we have obtained geochronological constraints on black shale deposition using the Re-Os system. We also study the response of Neoproterozoic marine carbonates to diagenetic alteration and fluid flow in order to identify “primary” compositions in such rocks that yield information on the chemical and isotopic composition of seawater at that time.

 Projects:

 - Sr, Nd and Li isotopes in carbonates of the Yangtze Platform and from Kazakhstan as tracers for the Ediacaran and Cambrian weathering history. S. Hohl, H. Becker, K. Hammerschmidt, U. Wiechert. Sub-project DFG FOR 736 (2011-2014) “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents”.

- Re-Os geochronology of black shales from the Neoproterozoic Doushantuo Formation, Yangtze platform, South China. B. Zhu, H. Becker, S.-Y. Jiang, D. Pi, M. Fischer-Gödde (2009-2011).

- U-Th-Pb Geochronology of Sediments from the Precambrian-Cambrian Transition, Yangtze Platform, China. W. Bäro, H. Becker, K. Hammerschmidt, Sub-project DFG FOR 736 (2008-2010) “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents”.