Figure 4: Schematic model of chemical fractionation by collisional erosion.
From: Cosmochemical fractionation by collisional erosion during the Earth’s accretion
(a,b) Early heating leads to the rapid segregation of Fe-rich metal into the core. It is accompanied with the formation of a deep magma ocean1 (a) and/or small-scale partial melting and formation of complex networks of veins and dikes4 (b) which allows fast transfer of melts to the surface4. Both can yield compositional stratification of the mantle and the formation of an SiO2-rich proto-crust. (c) The repeated collisions induce erosion of the proto-crust enriched in incompatible elements, as well as part of the planetary mantle. (d) Within the fraction of material volatilized by meteoritic impacts, re-condensation of refractory elements is favoured compared with the volatile elements.
