Stability of S-bearing minerals in the Earth's lower mantle

Sulfur is one of the five most abundant elements on Earth and it has played an important role in many geodynamic processes throughout the Earth's history, from core formation to modern subduction systems. While the behavior of sulfur in upper mantle processes is relatively well-studied due to direct access to natural samples, its behavior in the lower mantle remains unclear. We started investigating the reactions occuring between relevant oxidised phases, such as siderite (FeCO3) and hematite (Fe2O3), and CS2, as a source of sulfur and carbon. We will extend the characterization to Fe3O4 and FeO to investigate different redox conditions (spanning from the Fe3+ in Fe2O3 to Fe2+ in FeO passing through the mixed states of Fe3O4) and Al-bridgmanite in representation of different mantle geodynamic settings. This research aims to develop a deeper understanding of sulfur's behavior in complex Fe-S-C-O systems in the lower mantle and to provide insights on the deep sulfur cycle.