Question

How think is the crust under the mountain range?

Answer 1

Continental crust is thickest under mountain ranges, where it bulges downward into the mantle, forming a mountain root. Geophysical data also show that continental crust would “float” on oceanic crust because continental crust is less dense (continental crust, 2.7 g/cm 3; oceanic crust, 3.0 g/cm 3).

Answer 2

The crust is thickened by the compressive forces related to subduction or continental collision. The buoyancy of the crust forces it upwards, the forces of the collisional stress balanced by gravity and erosion. This forms a keel or mountain root beneath the mountain range, which is where the thickest crust is found.