A craton is the oldest part of a continental plate. It is an old and stable part of the continental lithosphere.After surviving cycles of merging and rifting of continents, cratons are usually found in the interiors of tectonic plates.ratonic lithosphere is much older than oceanic lithosphere – up to 4 billion years versus 180 million years. The term craton is used to distinguish the stable portion of the continental crust from regions that are more geologically active and unstable.