page_title: Plate tectonics
section_title: Thickness of plates
hierarchical_section_title: Plate tectonics / Earth's crust / Thickness of plates
caption_attribution_description: A cross section illustrating the main types of plate boundaries.
context_page_description: Plate tectonics is a theory of geology. It explains movement of the Earth's lithosphere: this is the earth's crust and the upper part of the mantle. The lithosphere is divided into plates, some of which are very large and can be entire continents.
  Heat from the mantle is the source of energy driving plate tectonics. Exactly how this works is still a matter of debate.
context_section_description: Ocean lithosphere varies in thickness. Because it is formed at mid-ocean ridges and spreads outwards, it gets thicker as it moves further away from the mid-ocean ridge. Typically, the thickness varies from about 6 kilometres (3.7 mi) thick at mid-ocean ridges to greater than 100 kilometres (62 mi) at subduction zones.
  Continental lithosphere is about 200 kilometres (120 mi) thick. It varies between basins, mountain ranges, and the stable cratonic interiors of continents. The two types of crust differ in thickness, with continental crust being much thicker than oceanic: 35 kilometres (22 mi) vs. 6 kilometres (3.7 mi).
caption: Three types of plate boundaries and a hot spot
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