lithosfeer

The lithosfeer, also known as the lithosphere in English, is the rigid outer shell of the Earth. It comprises the crust combined with the uppermost mantle and forms the layer on which tectonic plates move. The lithosphere sits above the more ductile asthenosphere, a part of the mantle that can flow slowly under stress.

There are two main types of lithosphere: continental and oceanic. Continental lithosphere is thicker and less dense, built largely from granitic rocks, and can reach depths of 150–250 kilometers or more. Oceanic lithosphere is thinner and more dense, consisting mainly of basaltic rocks, with typical thicknesses around 60–100 kilometers. The thickness and composition reflect the distinct processes that form the two types of crust.

The lithosphere is mechanically rigid, though it breaks and deforms at plate boundaries. The lithosphere-asthenosphere boundary (LAB) marks the transition to the underlying, more plastic mantle. Tectonic plates, which are portions of the lithosphere, move relative to each other at rates of a few centimeters per year. Their interactions at divergent, convergent, and transform boundaries drive earthquakes, volcanism, and mountain-building processes, and they control the creation and recycling of crust.

Age and recycling differ between the two types: oceanic lithosphere is relatively young and continually subducted back into the mantle, while continental lithosphere can be billions of years old and is not generally consumed at plate boundaries. The lithosfeer thus plays a central role in Earth's geodynamics and surface evolution.