PhD fellowship : Experimental magmatic geochemistry of sulfur isotopes

Sulfur has four stable isotopes: ³²S, ³³S, ³⁴S, and ³⁶S, with ³²S being the most common with 95% abundance. Typically, chemical reactions at high temperature do not differentiate between isotopes. However, fractionation of sulfur isotopes is observed in materials derived from volcanic eruptions, often attributed to fractionation during volcanic degassing. Though the mechanism and extent of this fractionation are not fully understood, several possible explanations exist. The proposed thesis project aims to quantify the fractionation of sulfur isotopes in geological settings related to volcanic eruptions, especially those involving silicic magmatic system. This research is conducted in a laboratory using one-of-a-kind gas mixing furnace system capable of replicating high-temperature magmatic conditions including redox states. The calibrated isotope fractionation values obtained are crucial for interpreting geochemical processes, allowing for quantitative assessments of sulfur budget and transfer inside the Earth. The applications of sulfur isotope geochemistry are diverse, encompassing topics such as Earth formation history, economic ore formation, and the assessment of magma flux beneath active volcanoes.