1. n. [Geology]
An interaction of lithospheric plates that can result in the formation of mountain belts and subduction zones. The collision of two plates of continental lithosphere, known as an A-type collision, can produce high mountains as rocks are folded, faulted and uplifted to accommodate the converging plates, as observed in the Alps and the Himalayas. B-type collisions, in which oceanic lithospheric plates collide with continental lithospheric plates, typically produce a subduction zone where the relatively denser oceanic plate descends below the relatively lighter continental plate, as seen on the Pacific coast of South America.