a term applied to a group of related rocks and to the area in which they crop out. Adjacent terranes do not have rocks which formed in the same geogra-phical area or were formed by similar geological processes.
A rock formation or continental plate fragment of lesser density which rides upon an oceanic plate of greater density. It may either join with other fragments,merge with a microplate, or finally dock with a major continental plate. The terranes of southeast Alaska have moved from distant regions and are called exotic terranes.
A rock formation or assemblage of rock formations that share a common geologic history. A geologic terrane is distinguished from neighboring terranes by its different history, either in its formation or in its subsequent deformation and/or metamorphism. Terranes are separated by faults. An exotic terrane is one that has been transported into its present setting from some distance.
n. A general term used to refer to a piece of the crust that is usually smaller than a continent but larger than an island; exotic terrane- n. terrane that has an unknown origin or a different origin than its surrounding rocks.
A terrane in paleogeography is an accretion that has collided with a continental nucleus, or "craton" but can be recognized by the foreign origin of its rock strata. The boundaries of a terrane are usually represented by crustal faults. In the lithospheric scheme of plate tectonics, a terrane is not a microplate, but a piece of crust "riding" atop another plate.