Sulfur biogeochemistry and global cycles
Sulfur isotope biogeochemistry, mainly focusing on microbial sulfate reduction and the reconstruction and interpretation of sulfur isotope variations in the geological record is long standing interest in our group.
Changes in the sulfur isotope composition of dissolved marine sulfate through time reflect changes in the global sulfur cycle and are also intimately related to changes in the carbon and oxygen cycles. A large shift in the sulfur isotope composition of sulfate at the Permian/Triassic boundary has been recognized for long time and a number of studies were carried out to understand the causes and significance of this shift. However, existing data for the rest of the Triassic are still relatively sparse and the stratigraphic evolution of the sulfur isotope composition of seawater is poorly constrained due to the small number of samples analyzed and/or due to the limited stratigraphic intervals studied. In addition, in the last few years the Triassic timescale has been significantly changed due to new radiometric data. Because of the inconsistencies in the timescales used, the correlation between different studies, and thus the construction of a generalized curve for the entire Triassic are very difficult. To obtain a more precise reconstruction of the evolution of the sulfur cycle in the Triassic we have analyzed Middle to Upper Triassic evaporites in Northern Switzerland and combined these new results with new and published data from evaporites from Germany, Austria and Italy to obtain a sulfur isotope reconstruction of most of the Triassic. We have revised the correlation between the well-dated marine Tethyan sections in northern Italy and the evaporites from the northern Switzerland and from the Germanic basin to improve the precision of the dating of the evaporites. We are now continuing by compiling carbon isotope records to better characterize changes in the carbon cycle and determine their links to the sulfur cycle.
Additionaly we are working on understanding the formation of native sulfur deposits around Salt diapirs, sulfate minerals in caves and sulfur cycling in lakes.
In collaboration with Dr. Peter Brack, Institute of Geochemistry and Petrology, ETH Zurich, Dr. Benjamin Brunner, University of Texas, El Paso , Prof. Mark Lever, D-USYS, ETH Zurich.
Contact
Geologisches Institut
Sonneggstrasse 5
8092
Zürich
Switzerland