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In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment. Then, the rock was buried underneath subsequent rock and was subjected to high pressures and temperatures, causing the rock to recrystallize. The overall composition of a metasedimentary rock can be ...
Metavolcanic rock is volcanic rock that shows signs of having experienced metamorphism. [1] In other words, the rock was originally produced by a volcano , either as lava or tephra . The rock was then subjected to high pressure, high temperature or both, for example by burial under younger rocks, causing the original volcanic rock to ...
the Lesser Himalayan Sequence, which is mainly composed of low-grade Proterozoic metasediments to unmetamorphosed rocks, fringed by the Main Boundary Thrust and the Main Central Thrust; the Greater Himalayan Crystalline complex, which is mainly composed by high-grade gneiss and migmatite , fringed below by the Main Central Thrust and the South ...
The rocks range in age from Precambrian to Miocene. The geology is complicated due to folding, faulting, and thrusting and are largely unfossiliferous. Tectonically, the entire Lesser Himalayas consists of two sequences of rocks: allochthonous, and autochthonous-para autochthonous units; with various nappes, klippes and tectonic windows.
Diabase, also known as dolerite – Type of igneous rock; Diorite – Igneous rock type Napoleonite, also known as corsite – Variety of diorite with orbicular structure; Dunite – Ultramafic and ultrabasic rock from Earth's mantle which is made of the mineral olivine; Essexite – Igneous rock type
The Greater Himalayan Crystalline complex, also known as the High Himalayan Crystalline Sequence, [14] is composed of high-grade metamorphic rocks aged between Paleoproterozoic and Ordovician. [4] Over the 4.5–8 km thick layer, paragneiss , schist and orthogneiss are observed.
Satellite image of the Himalayas Spatial arrangement of the Himalayan tectonostratigraphic zones. Modified from N.R. McKenzie et al 2011 [1]. Pre-collisional Himalaya is the arrangement of the Himalayan rock units before mountain-building processes resulted in the collision of Asia and India.
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. From east to west the Himalayas are divided into 3 regions, Eastern Himalaya, Central Himalaya, and Western Himalaya, which collectively house several nations and states.