My PhD focuses on two main aspects, the isotopic composition of sulfur and the isotopic composition of selenium. The first one is a well-known technique in the lab and can be used to investigate Archean sediments as well as carbonatites. The second one is the subject of a methodological development based on the new high resolution mass spectrometer, the Mat253 Ultra.
The samples I am interested in are from the Precambrian of Brazil, from more recent sedimentary rocks with a focus on the organic sulfur fraction, and from carbonatites which are a special kind of volcanic rocks. The main goal is to define the redox state or the redox evolution of these sytems through time. I am using for this the sulfur multi-isotopic composition, which means the three isotopic ratios of sulfur. Other tools can be carbon or oxygen isotopes.