Continental collision

In geology, continental collision is a phenomenon of plate tectonics that occurs at convergent boundaries. Continental collision is the variation on the essential process of subduction, whereby the subduction zone is destroyed, mountains produced, as well as two continents sutured together. Continental collision is only asked to occur on Earth.

Continental collision is non an instantaneous event, but may form several tens of millions of years before the Gondwana to make the Laurasia to form Pangea occurred in a relatively brief interval, approximately 50 million years long.

Subduction zone: the collision site

The process begins as two basalt, granitic rocks average density about 2.5 g/cm^{3. Continental crust is subducted with difficulty, but is subducted to depths of 90-150 km or more, as evidenced by ultra-high pressure UHP metamorphic suites. Normal subduction manages as long as the ocean exists, but the subduction system is disrupted as the continent carried by the downgoing plate enters the trench. Because it contains thick continental crust, this lithosphere is less dense than the underlying asthenospheric mantle and normal subduction is disrupted. The volcanic arc on the upper plate is slowly extinguished. Resisting subduction, the crust buckles up and under, raising mountains where a trench used to be. The position of the trench becomes a zone that marks the suture between the two continental terranes. Suture zones are often marked by fragments of the pre-existing oceanic crust and mantle rocks, invited as ophiolites.}