Experimental constraints on melting of mélanges in subduction zones

Basic data for this project

Description

In subduction zones, oceanic plates are recycled back into the Earth’s mantle. A typical plate consists of a large layer of peridotite, a km of altered basalt, and a thin layer of sediments of very variable compositions. Recent studies showed that the metabasalts do not melt in most subduction zones, but that pure sediments may get hot enough to allow for partial melting. However, field studies show that pure sediments are not frequently observed in nature and that subducted are mostly tectonic melanges, i.e., physical mixtures of sediments with metabasalt. The research project aims to study the behavior of tectonic melanges systematically. Experiments will be performed to study the solidus of different melanges at high pressures and high temperatures relevant to subduction zones. Furthermore, the experiments will constrain the chemical composition of partial melts and how these melts interact with the overlying mantle wedge in subduction zones.