Abstract:
The Earth formed 4.5Gy ago through a series of high-energy collisions between planetesimals and planetary embryos. The heat dissipated during this period induced widespread melting and the formation of magma oceans in which metal and silicates segregated to form the core and mantle. Importantly, core formation has been accompanied by a partitioning of composition and primordial heat between the core and mantle, which set the stage for the Earth' subsequent evolution and dynamics.
I will first discuss how geochemical data can be used to constrain the timing of core-formation and the distribution of equilibration conditions during Earth's accretion, and discuss the extent to which the interpretation of the geochemical data depends on assumptions made on the physical processes of metal-silicate separation. I will then present fluid dynamics experiments on metal-silicate separation following an impact, and propose simple models for the dispersion and fragmentation of the metal phase in a magma ocean, and for metal-silicate chemical exchange.