The geology of the Himalayas is a record of the most dramatic and visible creations of the immense

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...

formed by

plate tectonic Plate may refer to: Cooking * Plate (dishware), broad, mainly flat vessel commonly used to serve food * Plates, tableware, dishes or dishware used for setting a table, serving food and dining * Plate, the content of such a plate (for example: r ...

forces and sculpted by

weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...

and

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

. The

Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...

, 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 Orogeny () is a mountain-mountain formation, building process that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is tectonic uplift, u ...

— the collision of the

continental crust Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as '' continental shelves''. This layer is sometimes called '' si ...

of two

tectonic plates Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

, namely, the

Indian Plate The Indian plate (or India plate) is or was a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian plate broke away from the other fragments of Gondwana an ...

thrusting into the Eurasian Plate. The Himalaya-Tibet region supplies fresh water for more than one-fifth of the

world population In demographics of the world, world demographics, the world population is the total number of humans currently alive. It was estimated by the United Nations to have exceeded eight billion in mid-November 2022. It took around 300,000 years of h ...

, 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

rates at 2–12 mm/yr, the source of some of the greatest rivers and the highest concentration of

glaciers A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

outside of the

polar regions The polar regions, also called the frigid geographical zone, zones or polar zones, of Earth are Earth's polar ice caps, the regions of the planet that surround its geographical poles (the North Pole, North and South Poles), lying within the pol ...

. This last feature earned the Himalaya its name, originating from the

Sanskrit Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...

for "the abode of the snow". From south to north the Himalaya (Himalaya orogen) is divided into 4 parallel tectonostratigraphic zones and 5

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...

s which extend across the length of Himalaya orogen. Each zone, flanked by the thrust faults on its north and south, has

stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

(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

Nappe In geology, a nappe or thrust sheet is a large sheetlike body of rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the ...

s (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 The Trans himalaya (also spelled Trans-Himalaya), or "Gangdise – Nyenchen Tanglha range" ( zh, s=冈底斯-念青唐古拉山脉, p=Gāngdǐsī-Niànqīngtánggǔlā Shānmài), is a mountain range in China, India and Nepal, extending in a we ...

in Tibet which is outside the Himalayas. The Himalayas border the

Indo-Gangetic Plain The Indo-Gangetic Plain, also known as the Northern Plain or North Indian River Plain, is a fertile plain spanning across the northern and north-eastern part of the Indian subcontinent. It encompasses North India, northern and East India, easte ...

to the south,

Pamir Mountains The Pamir Mountains are a Mountain range, range of mountains between Central Asia and South Asia. They are located at a junction with other notable mountains, namely the Tian Shan, Karakoram, Kunlun Mountains, Kunlun, Hindu Kush and the Himalaya ...

to the west in

Central Asia Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...

, and the

Hengduan Mountains The Hengduan Mountains () are a group of mountain ranges in southwest China, southwest China that connect the southeast portions of the Tibetan Plateau with the Yunnan–Guizhou Plateau. The Hengduan Mountains are primarily large north-south ...

to the east on the China–Myanmar border. From east to west the Himalayas are divided into 3 regions,

Eastern Himalaya ] The Eastern Himalayas extend from eastern Nepal across Northeast India, Bhutan, the Tibet Autonomous Region to Yunnan in China and northern Myanmar. The climate of this region is influenced by the monsoon of South Asia from June to September. It ...

, Central Himalaya, and Western Himalaya, which collectively house Himalayan states, several nations and states.

Making of the Himalayas

During Late

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

and the

Palaeozoic The Paleozoic ( , , ; or Palaeozoic) Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of ...

, the

Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...

, bounded to the north by the Cimmerian Superterranes, was part of

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

and was separated from

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

by the

Paleo-Tethys Ocean The Paleo-Tethys or Palaeo-Tethys Ocean was an ocean located along the northern margin of the paleocontinent Gondwana that started to open during the Middle Cambrian, grew throughout the Paleozoic, and finally closed during the Late Triassic; ex ...

(Fig. 1). During that period, the northern part of

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

was affected by a late phase of the

Pan-African orogeny The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Oro ...

which is marked by an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

between

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

continental conglomerates and the underlying

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

marine

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

s. Numerous

granitic A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

intrusions dated at around 500 Ma are also attributed to this event. In the Early

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

, an early stage of rifting developed between the

and the Cimmerian Superterranes. During the Early

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

, this

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

developed into the Neotethys ocean (Fig. 2). From that time on, the Cimmerian Superterranes drifted away from Gondwana towards the north. Nowadays,

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central Asia and South Asia. It is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran borde ...

and

Tibet Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups s ...

are partly made up of these terranes. In the

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

(210 Ma), a major rifting episode split Gondwana in two parts. The Indian continent became part of East Gondwana, together with

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. However, the separation of East and West Gondwana, together with the formation of oceanic crust, occurred later, in the Callovian (160-155 Ma). The Indian plate then broke off from Australia and Antarctica in the Early

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

(130-125 Ma) with the opening of the "South Indian Ocean" (Fig. 3). In the Late

(84 Ma), the Indian plate began its very rapid northward drift covering a distance of about 6000 km, with the oceanic-oceanic

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

continuing until the final closure of the oceanic basin and the obduction of oceanic

ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle (Earth), upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is ...

onto India and the beginning of continent-continent

tectonic Tectonics ( via Latin ) are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of ''planetary tectonics'' extends the concept to other planets and moons. These processes ...

interaction starting at about 65 Ma in the Central Himalaya. The change of the relative speed between the Indian and Asian plates from very fast (18-19.5 cm/yr) to fast (4.5 cm/yr) at about 55 Ma is circumstantial support for collision then. Since then there has been about 2500 km of crustal shortening and rotating of India by 45° counterclockwise in the Northwestern Himalaya to 10°-15° counterclockwise in North Central Nepal relative to Asia (Fig. 4). While most of the

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramaf ...

was "simply" subducted below the Tibetan block during the northward motion of India, at least three major mechanisms have been put forward, either separately or jointly, to explain what happened, since collision, to the 2500 km of "missing

". * The first mechanism also calls upon the subduction of the Indian continental crust below Tibet. * Second is the extrusion or escape tectonics mechanism which sees the Indian plate as an indenter that squeezed the

Indochina Mainland Southeast Asia (historically known as Indochina and the Indochinese Peninsula) is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to th ...

block out of its way. * The third proposed mechanism is that a large part (~1000 km () or ~800 to ~1200 km) of the 2500 km of crustal shortening was accommodated by thrusting and folding of the sediments of the

passive Passive may refer to: * Passive voice, a grammatical voice common in many languages, see also Pseudopassive * Passive language, a language from which an interpreter works * Passivity (behavior), the condition of submitting to the influence of ...

Indian margin together with the deformation of the Tibetan crust. Even though it is more than reasonable to argue that this huge amount of crustal shortening most probably results from a combination of these three mechanisms, it is nevertheless the last mechanism which created the high topographic relief of the Himalaya. The Himalayan tectonics result in long term deformation. This includes shortening across the Himalayas that range from 900 to 1,500 km. Said shortening is a product of the significant ongoing seismic activity. The continued convergence of the Indian plate with the Eurasian plate results in mega earthquakes. These seismic events can reach greater than MW 8 and result in intense damage to infrastructure. The mid-crustal ramp in the Himalayas is a key geologic feature in the history for both long-term and short-term seismic processes linked to deformation and shortening. Over the last 15 Ma, the ramp has gradually moved south due to duplexing, accretion, and tectonic undercutting. The ongoing active collision of the Indian and Eurasian continental plates challenges one hypothesis for plate motion which relies on subduction.

Major tectonic subdivisions of the Himalaya

One of the most striking aspects of the Himalayan orogen is the lateral continuity of its major tectonic elements. The Himalaya is classically divided into four

units that can be followed for more than 2400 km along the belt (Fig. 5 and Fig. 7).

Sub-Himalayan (Churia Hills or Sivaliks) tectonic plate

The Sub-Himalayan tectonic plate is sometimes referred to as the ''Cis-Himalayan tectonic plate'' in the older literature. It forms the southern foothills of the Himalayan Range and is essentially composed of

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

molassic sediments derived from the erosion of the Himalaya. These

molasse __NOTOC__ In geology, "molasse" () are sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flys ...

deposits, known as the ''" Murree and Sivaliks Formations"'', are internally folded and imbricated. The Sub-Himalayan Range is thrust along the Main Frontal Thrust over the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

alluvium Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

deposited by the rivers coming from the Himalaya (

Ganges The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary rive ...

Indus The Indus ( ) is a transboundary river of Asia and a trans- Himalayan river of South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in the Western Tibet region of China, flows northwest through the dis ...

Brahmaputra The Brahmaputra is a trans-boundary river which flows through Southwestern China, Northeastern India, and Bangladesh. It is known as Brahmaputra or Luit in Assamese, Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, and ...

and others), which demonstrates that the Himalaya is still a very active orogen.

Lesser Himalaya (LH) tectonic plate

The Lesser Himalaya (LH) tectonic plate is mainly formed by Upper

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

to lower

detrital sediments from the passive Indian margin intercalated with some

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

s and

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

s (1840 ±70 Ma). These

sediments Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

are thrust over the Sub-himalayan range along the Main Boundary Thrust (MBT). The Lesser Himalaya often appears in tectonic windows (Kishtwar or Larji-Kulu-Rampur windows) within the High Himalaya Crystalline Sequence.

Central Himalayan Domain, (CHD) or High Himalaya tectonic plate

The Central Himalayan Domain forms the backbone of the Himalayan orogen and encompasses the areas with the highest topographic relief (highest peaks). It is commonly separated into four zones.

High Himalayan Crystalline Sequence (HHCS)

Approximately 30 different names exist in the literature to describe this unit; the most frequently found equivalents are ''"Greater Himalayan Sequence"'', ''" Tibetan Slab"'' and ''"High Himalayan Crystalline"''. It is a 30-km-thick, medium- to high-grade metamorphic sequence of metasedimentary rocks which are intruded in many places by granites of

(c. 500 Ma) and early

(c. 22 Ma) age. Although most of the metasediments forming the HHCS are of late

to early

age, much younger metasediments can also be found in several areas, e.g.

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

in the Tandi syncline of

Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...

and Warwan Valley of Kistwar in

Kashmir Kashmir ( or ) is the Northwestern Indian subcontinent, northernmost geographical region of the Indian subcontinent. Until the mid-19th century, the term ''Kashmir'' denoted only the Kashmir Valley between the Great Himalayas and the Pir P ...

in the ''"Tschuldo slice"'',

in the ''" Sarchu area"'' on Leh-Manali Highway. It is now generally accepted that the metasediments of the HHCS represent the

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

equivalents of the sedimentary series forming the base of the overlying ''" Tethys Himalaya"''. The HHCS forms a major

nappe In geology, a nappe or thrust sheet is a large sheetlike body of rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the ...

which is thrust over the Lesser Himalaya along the ''" Main Central Thrust"'' (MCT).

Tethys Himalaya (TH)

The Tethys Himalaya is an approximately 100-km-wide synclinorium formed by strongly folded and imbricated, weakly

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

sedimentary series. Several nappes, termed the ''"North Himalayan Nappes"'', have also been described within this unit. An almost complete

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

record ranging from the Upper Proterozoic to the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

is preserved within the

of the TH. Stratigraphic analysis of these sediments yields important indications on the geological history of the northern

continental margin A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental marg ...

of the Indian sub-continent from its Gondwanian evolution to its continental collision with

. The transition between the generally low-grade sediments of the ''"Tethys Himalaya"'' and the underlying low- to high-grade rocks of the ''"High Himalayan Crystalline Sequence"'' is usually progressive. But in many places along the Himalayan belt, this transition zone is marked by a major structure, the ''"Central Himalayan Detachment System"'', also known as the ''" South Tibetan Detachment System"'' or ''"North Himalayan Normal Fault"'', which has indicators of both extension and compression. See ''ongoing geologic studies'' section below.

Nyimaling-Tso Morari Metamorphic Dome (NTMD)

''"Nyimaling- Tso Morari Metamorphic Dome"'' in the

Ladakh Ladakh () is a region administered by India as a union territory and constitutes an eastern portion of the larger Kashmir region that has been the subject of a Kashmir#Kashmir dispute, dispute between India and Pakistan since 1947 and India an ...

region, the ''"Tethys Himalaya synclinorium"'' passes gradually to the north in a large dome of

greenschist Greenschists are metamorphic rocks that formed under the lowest temperatures and pressures usually produced by regional metamorphism, typically and 2–10 kilobars (). Greenschists commonly have an abundance of green minerals such as Chlorite ...

to eclogitic

rocks. As with the HHCS, these metamorphic rocks represent the metamorphic equivalent of the sediments forming the base of the Tethys Himalaya. The ''"

Phe Formation"'' is also here intruded by several

(c. 480 Ma) granites.

Lamayuru and Markha Units (LMU)

The Lamayuru and Markha Units are formed by

flysch Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building ep ...

s and olistholiths deposited in a turbiditic environment, on the northern part of the Indian

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margi ...

and in the adjoining Neotethys basin. The age of these sediments ranges from

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

Exhumation of Metamorphic Rocks

The metamorphic rocks of the Himalaya can be very useful in deciphering and coming up with models of tectonic relationships. According to Kohn (2014), the exhumation of metamorphic rocks can be explained by the Main Himalayan Thrust. Although the mechanism of emplacing higher grade metamorphic rocks on top of lower grade metamorphic rocks still strongly debated, Kohn believes that it is due to long periods of transportation of higher grade metamorphic rocks on the Main Himalayan Thrust. Essentially, the longer the higher grade rocks were spatially interacting with the thrust, the farther they were transported. The exhumation of eclogite and granulite rocks can be explained by several different models. The first model includes slab tear where the lower plate tore off into the mantle leading to high amounts of rebound. The second model states that the rocks got to a certain point in subduction and then were forced back up through the channel they came down due to a space problem. The third model states that the thick continental crust of India further exacerbated the space problem and caused the corner flow of those rocks back up the channel. The fourth model includes the rocks being transported along the Main Himalayan Thrust. Research on the Kumaon section of the Himalayas in 2011 showed the Higher Himalayan Crystalline (HHC) metamorphic series recorded at least four major stages of metamorphism: a pre-Indian/Asian collision stage, two differently-oriented stages during collision, and one of extension. Using apatite and zircon fission-track analysis, the researchers were also able to show that the ages of their samples did not change as one moved further north into the complex (from the main central thrust) even though samples were taken at different elevations. This implies a steady-state exhumation system where isotherms are parallel, so the distance rock travels as it is pushed upwards is uniform and thus, so is the speed of exhumation. The rate of erosion with respect to exhumation is thus also balanced.

Indus Suture Zone (ISZ) (or Yarlung-Tsangpo Suture Zone) tectonic plate

ISZ, also called Indus-Yarlung suture zone, Yarlung-Zangpo Suture Zone or Yarlung-Tsangpo Suture Zone, defines the zone of collision between the

and the Ladakh Batholith (also

or Karakoram-Lhasa Block) to the north. This suture zone is formed by: :* ''

Ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle (Earth), upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is ...

Mélange In geology, a mélange is a large-scale breccia, a mappable body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all sizes, contained in a fine-grained deformed matrix. The mélange typically con ...

s'', composed of an intercalation of

and

s from the Neotethys oceanic crust. :* '' Dras Volcanics'',

relicts A relict is a surviving remnant of a natural phenomenon. Biology A relict (or relic) is an organism that at an earlier time was abundant in a large area but now occurs at only one or a few small areas. Geology and geomorphology In geology, a r ...

of a

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

to Late

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

volcanic island arc and consist of

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

s, volcanoclastites,

pillow lava Pillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or ''subaqueous extrusion''. Pillow lavas in volcanic rock are characterized by thick sequences of discontinu ...

s and minor radiolarian

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

s :* ''

Molasse __NOTOC__ In geology, "molasse" () are sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flys ...

'', a continental

clastic rock Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks b ...

sequence (with rare interbeds of marine saltwater sediments) comprising

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

, braided stream and fluvio- lacustrine sediments derived mainly from the Ladakh batholith but also from the suture zone itself and the ''Tethys Himalaya''. These molasses are post-collisional and thus Eocene to post-Eocene. :* '' Indus Suture Zone'', representing the northern limit of the Himalaya. Further to the North is the so-called ''

'', or more locally ''

Batholith'', which corresponds essentially to an active margin of Andean type. Widespread

volcanism Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

in this

volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...

was caused by the melting of the mantle at the base of the Tibetan bloc, triggered by the

dehydration In physiology, dehydration is a lack of total body water that disrupts metabolic processes. It occurs when free water loss exceeds intake, often resulting from excessive sweating, health conditions, or inadequate consumption of water. Mild deh ...

of the

subducting Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second pla ...

Indian oceanic crust.

Seismic activity

The modern day rate of convergence between the Indian and Eurasian plates is measured to be approximately 17 mm/yr. This convergence is accommodated through seismic activity in active fault zones. As a result, the Himalayan range is one of the most seismically active regions in the world. This region has experienced many high magnitude earthquakes in the last 100 years, including the 1905 Kangra Earthquake, 1975 Kinnaur Earthquake, 1991 Uttarkashi Earthquake, and the 1999 Chamoli Earthquake, all of which were recorded at magnitudes equal or greater than Mw 6.6. A recent study (Parija et al, 2021) sought to quantify the

Coulomb Stress Transfer Coulomb stress transfer is a Seismology, seismic-related geology, geological process of Stress (mechanics), stress changes to surrounding material caused by local discrete deformation events. Using mapped displacements of the Earth's surface during ...

in the Western Himalayas. Coulomb stress transfer is used to quantify how earthquakes release stress, identifying areas that are put under increased stress and those that have been unloaded. This study and those like it are important in understanding the current state of fault zones in the region, as well as their potential for rupture in the future.

Notes

References

Citations

Sources

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

External links

*
"Geology and Petrographic study of the area from Chiraundi Khola to Thulo Khola, Dhading/Nawakot district, central Nepal".
MS Thesis by Gyanendra Gurung
Granitoids of the Himalayan Collisional Belt.
Special Edition of "The Journal of the Virtual Explorer"
Reconstruction of the evolution of the Alpine-Himalayan orogeny.
Special Edition of "The Journal of the Virtual Explorer"
"Engineering Geology of Nepal"Wadia Institute of Himalayan Geology, Dehradun, India, main page
{{DEFAULTSORT:Geology of the Himalaya Geology of Asia Himalayas Plate tectonics Geography of South Asia Landforms of South Asia Natural history of Asia Geology of Bhutan Geology of China Geology of India Geology of Nepal Geology of Pakistan Geology of Tibet

Himalaya The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than 100 pea ...