Oceanic lithosphere

Oceanic lithosphere is the rigid, outermost layer of Earth's crust beneath the oceans. Composed mainly of dense basaltic rocks, it forms the ocean floors and the upper part of the mantle. This layer is relatively thin, typically about 5-10 kilometers thick, but it is vital for plate tectonics because it moves and interacts with neighboring plates. As it cools and thickens over time, oceanic lithosphere becomes denser, eventually sinking back into the Earth's mantle at subduction zones. It plays a crucial role in shaping Earth's surface through processes like seafloor spreading, earthquakes, and volcanic activity.