Earth crust is the Thinnest and lightest layer. differentiated into Oceanic crust and Continental Crust.
|Oceanic crust||Continental Crust|
|Thinner 5km||thicker 80km|
|Fundamental. Recycled||continents were formed from oceans. Indestructible|
|Denser 3 - 3.5||?|
|NFMS, Silica ??|
The first crust - The first crust formed was probably because of cooling of the planet from ancient nebulae.
meteorite impact - In the absence of the atmosphere, the earths Surface must have been ovewhelmed by meteorite impact
volcanic eruptions - meteorite impact must have cracked the earth crust at numerous places resulting in pressure release of mantle, mantle turbulence, first convection cells and numerous volcanic eruptions on the surface.
volcanic eruptions must have been extremely mafic even after partial melting of the mantle rocks.
first ocean/ Basalt - Those Mafic eruptions must have subducted many times and recycled before the first ocean. Basalt was formed.
first continental andesite / micro continent - The subduction of this first ocean basalt must have created the first continental andesite. These were the first micro continent and once formed can float and resist subduction.
first fold mountains / proto continent - The micro continents must have collided with one another fused forming larger continent and first fold mountains must have been formed - proto continent
Eg. Peninsular India has numerous, such micro continent which have been fused.
The 3 major micro / proto continents were Singbhum proto continent, Dharwad proto continent and aravalis proto continent which fused along Narmada - Son - Godavari lineament
ancient fold Mountains - Every time the continents collide, there must have formed ancient fold Mountains. The aravalis are remnants of such ancient fold mountains.
This process of techtonic dynamism is found in no other planet and may to some extent in venus hence No other planethas the type of crust our earth has or the fold Mountain our earth has.
The process in the origin / evolution of earth is not same as the theories and processes in the origin of earths crust.