What term refers to the great pressure that causes deformation in rock layers?

The term that refers to the great pressure causing deformation in rock layers is diastrophism. Diastrophism encompasses the processes that lead to changes in the shape, position, or volume of the Earth's crust due to tectonic forces. This transformation can result in various geological phenomena, including folds, faults, and other structural features of the Earth's crust.

Diastrophism often involves the interplay of compressive forces, which can lead to the deformation of rocks. Unlike compression, which specifically refers to the type of stress exerted on materials, diastrophism describes the broader spectrum of tectonic activity resulting from these forces over extended periods. This makes diastrophism a more comprehensive term when discussing the ultimate effects of such pressures on rock formations.

Subduction refers to a specific geological process where one tectonic plate moves under another, plunging into the mantle, while metamorphism involves changes in rock composition and structure due to heat and pressure, but it doesn't primarily denote the cause of deformation.