GENERAL GEOLOGY

Detailed explanation-1: -Decompression melting takes place within Earth when a body of rock is held at approximately the same temperature but the pressure is reduced. This happens because the rock is being moved toward the surface, either at a mantle plume (a.k.a., hot spot), or in the upwelling part of a mantle convection cell.

Detailed explanation-2: -Decompression MeltingDecompression melting involves the upward movement of Earth’s mostly-solid mantle. This hot material rises to an area of lower pressure through the process of convection. Areas of lower pressure always have a lower melting point than areas of high pressure.

Detailed explanation-3: -Geothermal Gradient This heat is caused by residual heat left from the formation of Earth and ongoing radioactive decay. The rate at which temperature increases with depth is called the geothermal gradient. The average geothermal gradient in the upper 100 km (62 mi) of the crust is about 25°C per kilometer of depth.

Detailed explanation-4: -Magma are rocks that melted when subjected to high temperature and pressure. Magmatism is the activity or the motion of magma. Plutonism is the formation of intrusive igneous rocks through the solidification of magma beneath the Earth’s surface.

Detailed explanation-5: -Decompression melting commonly occurs at divergent plate boundaries, where two tectonic plates are moving away from each other. Mid-ocean ridges are the classic example, but adiabatic melting also occurs during continental lithospheric extension and in some mantle plumes.