Knowra Oceanic lithosphere Oceanic lithosphere Oceanic lithosphere is the rigid layer beneath ocean basins, comprising oceanic crust and the uppermost mantle. It forms at mid-ocean ridges and is recycled into the mantle at subduction zones.
Seafloor spreading : The process by which magma rising at mid-ocean ridges creates new ocean floor that moves away from the ridge. Spreading adds new crust and mantle to oceanic lithosphere at ridge axes.
Mohorovičić discontinuity : The seismic boundary between Earth's crust and mantle, marked by a sharp increase in seismic-wave velocity. It separates oceanic crust from the mantle portion of the lithosphere.
Mid-Atlantic Ridge : A divergent plate boundary running along the floor of the Atlantic Ocean where new oceanic crust forms. It is a prominent site where young oceanic lithosphere is created.
Continental lithosphere : The rigid outer layer beneath continents, comprising continental crust and the uppermost mantle. It is thicker, compositionally different, and generally older than oceanic lithosphere.
Oceanic crust : The thin, solid rock layer forming the seafloor, composed chiefly of basalt and gabbro. It is the upper component of oceanic lithosphere.
Asthenosphere : The weak, slowly deforming upper-mantle region beneath the lithosphere. Its ability to flow distinguishes it mechanically from the rigid layer above.
East Pacific Rise : A fast-spreading mid-ocean ridge in the eastern Pacific Ocean. Its rapid spreading provides a clear case of lithosphere formation at a ridge.
Continental crust : The relatively thick, low-density crust underlying continents, composed largely of granitic rocks. Its composition and buoyancy contrast with the thin, dense oceanic crust.
Lithospheric mantle : The cool, rigid uppermost mantle mechanically attached to the crust as part of a tectonic plate. It lies beneath oceanic crust and completes the lithosphere.
Oceanic plate : A moving tectonic plate that carries oceanic lithosphere and may also include continental lithosphere. The lithosphere is the rigid material that moves as part of a plate.
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