Craton

Uncommon card · No. 136031

In geology, a craton ( KRAYT-on, KRAT-on, or KRAY-tən; from Ancient Greek κράτος (kratos) 'strength') is an old and stable part of continental lithosphere (the Earth's two topmost layers, the crust and the lithospheric mantle). Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates; the exceptions occur where geologically recent rifting events have separated cratons and created passive margins along their edges. Cratons are composed of ancient crystalline basement rocks covered by younger sedimentary rocks. They have a thick crust and deep lithospheric roots extending several hundred kilometres into Earth's mantle. This crust consists of shields and platforms. Shields are made of basement rock and are visible, while platforms are the portion not visible made up of sedimentary rock. Cratons contain the oldest continental crust rocks on Earth. They were formed in the Archaean (4 to 2.5 billion years ago) and the...

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