Craton

A craton is an ancient, tectonically stable part of a continent, made of thick continental crust and its underlying lithospheric mantle. Its resistant interior has survived repeated cycles of continental assembly and breakup.

Continental crust: The low-density, silica-rich outer layer of Earth that forms the continents. Its thick, buoyant roots form the upper part of a craton.
Continental lithosphere: The rigid crust and uppermost mantle that make up the tectonic plates beneath continents. A craton is an especially thick and stable portion of continental lithosphere.
Hadean: The earliest geological eon, from Earth's formation to about four billion years ago. The processes that produced Earth's first continental nuclei began in this poorly preserved interval.
Kaapvaal Craton: An ancient craton in southern Africa that preserves extensive Archean crust and mantle rocks. Its exposed rocks and diamonds make it a major record of cratonic evolution.
Lithospheric mantle: The rigid uppermost mantle attached to Earth's crust and moving with it as a tectonic plate. Its deep, cool root helps make cratonic interiors mechanically stable.
Lithospheric keel: A deep, thick root of strong lithosphere extending beneath a tectonic plate. Cratonic keels anchor ancient continental interiors far below ordinary crust.
Archean: The geological eon from about four billion to 2.5 billion years ago. Much of the oldest surviving cratonic basement formed during the Archean.
Pilbara Craton: An ancient craton in Western Australia containing exceptionally old continental rocks. Its well-preserved Archean sequences offer a detailed case of early crustal development.
Shield (geology): A broad area of ancient crystalline rocks exposed at Earth's surface. Shields expose the old basement that lies beneath many cratons.
Geotherm: The variation of temperature with depth inside Earth. Cratonic geotherms are relatively cool, helping preserve strong mantle roots.

Linked from 28 pages