Accretion of the Earth and the formation of the Earth's Crust

Danilo Antón

At the time of the original accretion of the Earth due to the strong impactsl various physical and mineralogical changes occurred. According to Vicente Sanchez Cela, because of these impacts, predominantly crystalline silicate structures, composed of dense mineral.
This influenced the initial composition of the original earth materials. The aforementioned author considers that the minerals formed under these conditions would be the Coesite: SiO2, density: 2.92, the stishovite, SiO2, density 4.35, K-Na Holandita: (K, Na) AlSi3O8, density: 4.5, the silicate perovskite (Mg, Fe) SiO 3 and CaSiO3, density. 4.y post-perovskite MgSiO3; PPV, .densidad 4.0.
The composition of meteorites, particularly the most common ones, the L-chondrites give an idea about other minerals that may have been present in the planetesimals. By order of abundance they are: olivine (Mg, Fe) 2SiO4 density: 3.27-3.37; hypersthene (Mg, Fe) SiO3d, density: 3.3-3.9; FeS troilite, density 4.67-4.79; FeCr2O4, chromite, density: 4.5-4.8; sodium feldspar: NaSi3AlO8, density; 2.61; calcium phosphate: Ca (H2PO4) 2 Density: 2.2.
This chondrite composition reaffirms the notion of dominance of silicate minerals with abundant iron and magnesium. Lesser extent are found of sulfides and oxides, alumino-silicates and sodium and calcium phosphates
In conclusion, the original materials of the planet were mainly composed of silicates. The diifferences between different levels would not compositional,  but related to the respective densities of the  different mineral phases.
The gradual phase shift of the silicate minerals meant that, on the outer levels of the planet, a crust was gradually formed with smaller density. This layer is what we call "the crust".