Synthesis of amorphous MgO-rich peridotitic starting material for laser-heated diamond anvil cell experiments – application to iron partitioning in the mantle

We report the preparation of the starting material reflecting the complex composition of the Earth's mantle. With this aim, we synthesized two types of material: sol-gel and glass obtained by aerodynamic levitation. Thanks to their high homogeneity and reactivity, these materials are suitable for experimental petrology under extreme conditions, conducted in laser-heated diamond anvil cell. We then used this mantle analog to investigate the iron partitioning between high pressure phases under lower mantle conditions during solid-state reaction and partial melting of the material. Iron preferentially partitions into the (Mg,Fe)O, but the presence of aluminum slightly enriches iron in the silicate phase (Kpv-fp=0.41 +/- 0.04) compared to similar experiments in an Al-free system.