litosferic

Litosferic, in geology, refers to anything related to the lithosphere, the rigid outer shell of the Earth. The lithosphere comprises the crust and the rigid, uppermost portion of the mantle. Its thickness varies: continental lithosphere is roughly 100 to 200 kilometers thick, while oceanic lithosphere is thinner, about 65 to 100 kilometers, and generally more dense.

Mechanically, the lithosphere behaves as a solid shell that moves as a set of tectonic plates. These plates ride over the underlying, more ductile asthenosphere, allowing relative motion that drives plate tectonics. The base of the lithosphere is marked by a transition into the partially molten mantle, where the asthenosphere begins; the crust–mantle boundary within the lithosphere is commonly referred to as the Mohorovičić discontinuity (Moho).

Composition varies by type. Continental lithosphere contains granitic or granodioritic crust with underlying mantle lithosphere composed mainly of peridotite. Oceanic lithosphere consists largely of basaltic crust overlying depleted mantle peridotite. The two types differ in density, composition, and age, which influences their buoyancy and behavior at plate boundaries.

Age and dynamics: oceanic lithosphere is continually created at mid-ocean ridges and recycled back into the mantle through subduction, generally remaining younger than about 200 million years. Continental lithosphere can be far older and is less readily recycled. Lithospheric processes underpin many geologic phenomena, including earthquakes, volcanic activity, and orogeny, through the movement and interaction of tectonic plates.