What is a craton?
Q: What is a craton?
A: A craton is the oldest part of a continental plate, made up of ancient crystalline basement rock, and is an old and stable part of the continental lithosphere.
Q: Where are cratons usually found?
A: After surviving cycles of merging and rifting of continents, cratons are usually found in the interiors of tectonic plates.
Q: What is the composition of a craton?
A: Cratons are composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep roots that extend as much as several hundred kilometers into the Earth's mantle.
Q: How does the age of cratonic lithosphere compare to the age of oceanic lithosphere?
A: Cratonic lithosphere is much older than oceanic lithosphere – up to 4 billion years versus 180 million years.
Q: What is the purpose of using the term "craton"?
A: The term craton is used to distinguish the stable portion of the continental crust from regions that are more geologically active and unstable.
Q: What are shields and platforms when referring to cratons?
A: Cratons can be described as shields, in which the basement rock crops out at the surface, and platforms, in which the basement is overlain by sediments and sedimentary rock.
Q: How are cratons subdivided geographically?
A: Cratons are subdivided geographically into geologic provinces, which are areas with common geologic properties.
