This is a list of tectonic plates on the Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with basaltic rocks ("mafic") dominating oceanic crust, while continental crust consists principally of lower-density granitic rocks ("felsic"). See also Plate tectonics.
Geologists generally agree that the following tectonic plates currently exist on the Earth's surface with roughly definable boundaries. Tectonic plates are sometimes subdivided into three fairly arbitrary categories: major (or primary) plates, minor (or secondary) plates, and microplates (or tertiary plates).
These plates comprise the bulk of the continents and the Pacific Ocean. For purposes of this list, a major plate is any plate with an area greater than 20 million km2.
These smaller plates are often not shown on major plate maps, as the majority do not comprise significant land area. For purposes of this list, a minor plate is any plate with an area less than 20 million km2 but greater than 1 million km2.
These plates are often grouped with an adjacent major plate on a major plate map. For purposes of this list, a microplate is any plate with an area less than 1 million km2. Some models identify more minor plates within current orogens like the Apulian, Explorer, Gorda, and Philippine Mobile Belt plates. There may or may not be scientific consensus as to whether such plates should be considered distinct portions of the crust, thus new research could change this list.