Geology of the Himalaya in the context of China–Myanmar border

⭐ Core Definition: Geology of the Himalaya

The geology of the Himalayas is one of the most dramatic and visible creations of the immense mountain range formed by plate tectonic forces and sculpted by weathering and erosion. The Himalayas, which stretch over 2400 km between the Namcha Barwa syntaxis at the eastern end of the mountain range and the Nanga Parbat syntaxis at the western end, are the result of an ongoing orogeny — the collision of the continental crust of two tectonic plates, the Indian Plate thrusting into the Eurasian Plate. 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.

From south to north the Himalaya (Himalaya orogen) is divided into 4 parallel tectonostratigraphic zones and 5 thrust faults which extend across the length of Himalaya orogen. Each zone, flanked by the thrust faults on its north and south, has stratigraphy (type of rocks and their layering) different from the adjacent zones. From south to north, the zones and the major faults separating them are the Main Frontal Thrust (MFT), Subhimalaya Zone (also called Sivalik), Main Boundary Thrust (MBT), Lesser Himalaya (further subdivided into the "Lesser Himalayan Sedimentary Zone (LHSZ) and the Lesser Himalayan Crystalline Nappes (LHCN)), Main Central thrust (MCT), Higher (or Greater) Himalayan crystallines (HHC), South Tibetan detachment system (STD), Tethys Himalaya (TH), and the Indus‐Tsangpo Suture Zone (ISZ). North of this lies the Transhimalaya in Tibet which is outside the Himalayas. The Himalayas border the Indo-Gangetic Plain to the south, Pamir Mountains to the west in Central Asia, and the Hengduan Mountains to the east on the China–Myanmar border.

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⭐ Core Definition: Geology of the Himalaya
Geology of the Himalaya in the context of Continental collision
Geology of the Himalaya in the context of Zanskar Range
Geology of the Himalaya in the context of Leucogranite

Geology of the Himalaya in the context of Continental collision

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

Continental collision is not an instantaneous event, but may take several tens of millions of years before the faulting and folding caused by collisions stops. The collision between India and Asia has been going on for about 50 million years already and shows no signs of abating. Collision between East and West Gondwana to form the East African Orogen took about 100 million years from beginning (610 Ma) to end (510 Ma). The collision between Gondwana and Laurasia to form Pangea occurred in a relatively brief interval, about 50 million years long.

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Geology of the Himalaya in the context of Zanskar Range

The Zanskar Range is a mountain range in the union territory of Ladakh that separates the Zanskar valley from Indus valley at Leh. The range lies between and runs parallel to the Great Himalayas to the southwest and the Ladakh Range to the northeast. Geologically, the Zanskar Range is part of the Tethys Himalaya. There are a number of peaks higher than 6,500 m (21,300 ft). Its eastern part is known as Rupshu.

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Geology of the Himalaya in the context of Leucogranite

Leucogranite is a light-colored, granitic, igneous rock containing almost no dark minerals.

Leucogranites have been reported from a variety of orogenies involving continental collisions. Examples include the Black Hills (Trans-Hudson orogeny of Proterozoic age), the Blue Ridge basement complex (Grenville orogeny of Proterozoic age), the Paleozoic Appalachian orogeny in Maine, and the currently active Himalayan orogeny. The leucogranite magmas are interpreted to have been derived by partial melting of pelitic rocks in the upper portions of thickened crust. These melts result following deformation and metamorphism, but the heat source is uncertain. Shear-heating associated with large shear zones in the crust has been proposed as the mechanism.

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