Island arc systems now on the tibet plateau record subduction prior to the collision of india with eurasia. geologists would map these pre-collisional arc rocks as

Geologists would map these pre-collisional arc rocks as terranes. A terrane is a piece of a landmass, limited by structural flaws, which is diverse from various perspectives from the principal landmass to which it is connected. Geologists attribute this to the terranes having initially been separate from the principal landmass, and being borne up against the edge of the landmass by the movement of plates.