Overthrusting

Overthrusting is a geological process in which a large block of rock is thrust over an adjacent block of rock along a nearly horizontal fault. This process is often associated with the formation of mountain ranges and is a key component of orogenic processes, which are the forces that shape the Earth's crust. Overthrusting typically occurs in convergent plate boundaries, where two tectonic plates collide, and one plate is forced beneath the other in a process known as subduction. However, in some cases, the overriding plate can become so thick and buoyant that it is unable to subduct, leading to overthrusting instead.

The rocks involved in overthrusting are subjected to intense pressure and deformation, leading to the formation of complex structures such as folds, faults, and thrust faults. These structures can be observed in the field as a series of parallel ridges and valleys, known as anticlines and synclines, respectively. Overthrusting can also lead to the formation of metamorphic rocks, as the rocks are subjected to high temperatures and pressures.

Overthrusting is a significant process in the formation of mountain ranges, such as the Himalayas and the Alps. In these regions, the collision of two continental plates has led to the overthrusting of one plate over the other, resulting in the uplift of the Earth's crust and the formation of high, rugged mountains. The process of overthrusting is ongoing in these regions, and the mountains continue to grow and change shape over time.