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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 ...
Metasomatism (from the Greek μετά metá "change" and σῶμα sôma "body") is the chemical alteration of a rock by hydrothermal and other fluids. [1] It is traditionally defined as metamorphism which involves a change in the chemical composition, excluding volatile components. [2]
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.
For example, if the protolith is known to be basalt, the rock will be described as a metabasalt. Likewise, a metamorphic rock whose protolith is known to be a conglomerate will be described as a metaconglomerate. For a metamorphic rock to be classified in this manner, the protolith should be identifiable from the characteristics of the ...
A metamorphic rock, deformed during the Variscan orogeny, at Vall de Cardós, Lérida, Spain. To many geologists, regional metamorphism is practically synonymous with dynamothermal metamorphism. [30] This form of metamorphism takes place at convergent plate boundaries, where two continental plates or a continental plate and an island arc collide
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.
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.
The Vishnu Basement Rocks is the name recommended for all Early Proterozoic crystalline rocks (metamorphic and igneous) exposed in the Grand Canyon region. They form the crystalline basement rocks that underlie the Bass Limestone of the Unkar Group of the Grand Canyon Supergroup and the Tapeats Sandstone of the Tonto Group.