Paired garnet-clinopyroxene inclusions in diamonds – implications to the fate of subducted slab

During crystallisation, a small proportion of diamonds (no more than 2%), captures tiny inclusions of other minerals. In rare cases, inclusions of different minerals are captured simultaneously. Here we propose to implement the Synchrotron Mössbauer Source (beamline ID14) in order to measure Fe3+/Fe2+ in paired garnet-clinopyroxene inclusions. These inclusions are of eclogitic origin meaning that at some point in time they were at the surface, and were later transported into the deep mantle by subduction. The study of these inclusions will permit us not only to identify the oxidation state of the upper mantle eclogitic rocks, but to also assess how oxidised is the material transported by subduction. This study will have important implications to the mantle rheology and transport properties as well as to mantle convection and material circulation by subduction