Geology of the Himalaya

The geology of the Himalaya is a record of the most dramatic and visible creations of modern plate tectonic forces. The Himalayas, which stretch over 2400 km between the Namche Barwa in Tibet and the Nanga Parbat syntaxis in India, are the result of an ongoing orogeny — the result of a collision between two continental tectonic plates. This immense mountain range was formed by tectonic forces and sculpted by weathering and erosion. The Himalaya-Tibet region supplies fresh water for more than one-fifth of the world population, and accounts for a quarter of the global sedimentary budget. Topographically, the belt has many superlatives: the highest rate of uplift (nearly 10 mm/year at Nanga Parbat), the highest relief (8848 m at Mt. Everest Chomolangma), among the highest erosion rates at 2–12 mm/yr, the source of some of the greatest rivers and the highest concentration of glaciers outside of the polar regions. This last feature earned the Himalaya its name, originating from the Sanskrit for "the abode of the snow".

During Late Precambrian and the Palaeozoic, the Indian Subcontinent, bounded to the north by the Cimmerian Superterranes, was part of Gondwana and was separated from Eurasia by the Paleo-Tethys Ocean (Fig. 1). During that period, the northern part of India was affected by a late phase of the Pan-African orogeny which is marked by an unconformity between Ordovician continental conglomerates and the underlying Cambrian marine sediments. Numerous granitic intrusions dated at around 500 Ma are also attributed to this event.

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