Formation of the Earth and the other terrestrial planets of our Solar System (Mercury, Venus and Mars) commenced 4.567 billion years ago and occurred on a time scale of about 100 million years. These planets grew by the process of accretion, which involved numerous collisions with smaller (Moon- to Mars-size) bodies. The energy of such collisions caused large-scale melting and the formation of deep “magma oceans”. Such magma oceans enabled liquid metal to separate from liquid silicate, sink and accumulate to form the metallic cores of the planets. Thus core formation in terrestrial planets was a multistage process, intimately related to major collisions during accretion, which determined the resulting chemistry of planetary mantles. The aim of this interdisciplinary ERC project is to integrate astrophysical models of planetary accretion with geochemical models of planetary differentiation, with cosmochemical constraints also being provided by meteorites. The research will involve integrating new models of planetary accretion with core formation models based on the partitioning of elements between liquid metal and liquid silicate that we will determine experimentally at pressures up to about 100 gigapascals (equivalent to 2400 km deep in the Earth). By comparing our results with the known physical and chemical characteristics of the terrestrial planets, we will obtain a comprehensive understanding of how these planets formed, grew and evolved, both physically and chemically, with time.
