Forty million years ago, the continent of India, which was being carried northward by the Indo-Australian plate, collided with Asia. Since the initial encounter, the subcontinent of India has moved 2,000 kilometers farther north at a rate of 5 centimeters a year, sliding beneath Asia as it moves. Consequently, the crust has become unusually thick, reaching a maximum of 78 kilo-meters beneath the Tibetan plateau. This thick, light crust rides atop the denser mantle, adding to the Himalayas’ great height.
