A because it’s based on the environment and the society
Answer:
Partial melting occurs when only a portion of solid is melted. It is thus enriched in the chemical components of minerals with lower melting temperatures and the remaining unmelted portion of the rock is composed of minerals with highest melting temperatures. Partial melting preferentially enriches melts with incompatible elements.
Partially melted rock do not usually experience complete melting inside the Earth, due to their different chemical composition and their melting points.
It is thought that partial-melting processes play a major role in generating more-defined liquids from less-evolved ones, so that many basalts may be the result of partial melting in the upper mantle, and many granites may have derived partly or completely from the partial melting of continental crust (anatexis).With increasing temperature and pressure, the subducted oceanic crust (of basic composition) first undergoes metamorphism and then begins to melt or release watery fluids; this material rises into the overlying mantle, which may also begin to melt, giving rise to intermediate magma.
Both plates are folded into mountain ranges
Oceanic Crust
Continental Crust
Oceanic crust is denser than continental, this is why continents are at higher elevation than oceans.
