Geology Himalaya

The Himalayan range is one of the youngest mountain ranges on the planet and consists mostly of uplifted sedimentary and metamorphic rock. According to the

modern theory of plate tectonics, its formation is a result of a continental collision or orogeny along the convergent boundary (Main Himalayan Thrust) between the Indo-Australian Plate and the Eurasian Plate. The Arakan Yoma highlands in Myanmar and the Andaman and Nicobar Islands in the Bay of Bengal were also formed as a result of this collision.

During the Upper Cretaceous, about 70 million years ago, the north-moving Indo-Australian Plate (which has subsequently broken into the Indian Plate and the

Australian Plate[14]) was moving at about 15 cm (5.9 in) per year. About 50 million years ago this fast moving Indo-Australian Plate had completely closed the Tethys Ocean, the existence of which has been determined by sedimentary rocks settled on the ocean floor and

the volcanoes that fringed its edges. Since both plates were composed of low density continental crust, they were thrust faulted and folded into mountain ranges rather than subducting into the mantle along an oceanic trench.[13] An often-cited fact used to illustrate this process is that the summit of Mount Everest is made of marine limestone from this ancient ocean.[15]