TheThar Desert (Hindi pronunciation:[t̪ʰaːɾ]), also known as theGreat Indian Desert, is anarid region in the north-western part of theIndian subcontinent stretching across India and Pakistan. Spread across an area of 264,091 km2 (101,966 sq mi), it is one of thelargestsubtropicaldeserts in Asia by area. About two-thirds of the desert area lies in India, with the remaining in Pakistan. It forms about six percent of the geographical area of India, with majority of the desert lying in thestate ofRajasthan, with portions extending intoGujarat,Haryana, andPunjab. Towards the west, it extends into theprovinces ofSindh andPunjab in Pakistan. It is bordered by theIndo-Gangetic Plain to the north, west and northeast,Rann of Kutch to the south, and theAravali Range to the east.
The topography consists of sandy plains intercepted by eroded hills of low elevation. The region has a tropicaldesert climate with extremely hotsummers and coolerwinters. Majority of the rainfall is obtained from thesouthwest monsoon, which on average is less than 500 mm (20 in) annually. The rainfall varies over the years, often with large spells of drought. There are very few sources of water, with the inlandLuni River system being the only major river system in the region. Rain water is often stored in natural and man-madereservoirs for use in the dry season.
The natural vegetation of the region is composed of trees, thornyscrubs and scatteredgrasslands. The desert is home to several animal and bird species. The Thar Desert is one of the most widely populated deserts in the world, with theThar people inhabiting the area. The population is clustered into small villages, with majority of themnomadic in nature. Limitedagriculture,herding of animals, andeco tourism drive the economy of the region.
The Thar Desert is located in the north-western part of theIndian subcontinent stretching across the border between India and Pakistan, and is the eastern most extension of theSahara–Arabian desert formation.[1][4] It is spread across an area of 264,091 km2 (101,966 sq mi), with 195,091 km2 (75,325 sq mi) of the desert area lying in India, with the remaining in Pakistan. The desert forms about six percent of the geographical area of India, with majority of the desert lying in the state ofRajasthan, with portions extending intoGujarat,Haryana, andPunjab.[1][4] Towards the west, it extends into the provinces ofSindh andPunjab in Pakistan.[1][5] The northeastern part of the Thar Desert lies between theAravalli Hills, which separates the same from theCentral highlands and theIndo-Gangetic Plain to the east. The desert stretches from the alluvial plains of theIndus River in the west and northwest, to theGreat Rann of Kutch in the south.[1]
In theMesozoic era (252 to 66mya), the area was a low lyingpeneplain, covered by shallow waters.Erosion resulted in the formation of three layers ofplanation surfaces during the post-Mesozoic (66 to 2.6 mya), and earlyPleistocene (2.6 mya to 11,000 years ago) periods. As theHimalayas arose during the mid-Miocene period (23.4 to 5.3 mya), it gave rise to themonsoon.[4]
During theLast Glacial Maximum (26,000–20,000 years ago), an estimated 2,400,000 km2 (930,000 sq mi)ice sheet covered theTibetan Plateau.[6][7][8] The lowlatitude ice sheet significantly affectedradiative forcing, and reflected at least four times moresolar radiation per unit area into space than ice at higher latitudes, resulting in further cooling of the overlying atmosphere during that period.[9] Without thethermal low pressure caused by the heating, there was no monsoon over theIndian subcontinent. This lack of monsoon causedextensive rainfall over the Sahara region, while resulted in more dust deposited towards theArabian Sea in the east. It also resulted in changes to thebiotic life zones on the Indian subcontinent, as fauna responded to this shift in climate with species likeJavan rusa deer migrating into India.[10]
TheAravalli Range formed rapidly, and reached significant altitude during the earlyHolocene period (11,700 years ago).[4] Between 10,000 and 8,000 years ago, a channel of theGhaggar-Hakra River, identified with the paleoSarasvati River, after its confluence with theSutlej River flowed into theNara River, adelta channel of theIndus River, but then changed its course. The upliftment of the Aravallis brought about changes in the hydrography of the region, with increase in waters flowing through theYamuna River, while depriving the headwaters of the Ghaggar-Hakra system.[4] This left the Ghaggar-Hakra as a system of monsoon-fed rivers that no longer reached the sea, which ended up in the Thar desert.[11][12][13][14] Starting from around 4,500 to 5,000 years ago, when the monsoons that fed the river system diminished further, as the Aravallis blocked the monsoon winds from the east, the region becameincreasingly arid. TheIndus Valley Civilisation had prospered in the area,[11][13][14][a] with several settlements along the course of the river system.[15][16] When monsoons diminished even further, the dried-up Hakra became an intermittent river, and the urban Harappan civilisation declined, becoming localized in smaller agricultural communities.[11][b][13][12][14] Over the years, sand accumulated due to wind blownsediments from the alluvial plains and the coast.[4]
The eastern part of the Thar Desert, that lies in the western foothills of the Aravallis, consists of sandy plains intercepted by eroded hills of low elevation. It rises to about 325 m (1,066 ft) in elevations as it reaches the Aravallis, which continue as the plateau of the central India beyond the range. The sandy plains extend across to the west, with the altitude dropping to 150 m (490 ft) at theIndia-Pakistan border.[1] Much of the desert area is covered bysand dunes that are formed due to accumulation of wind blown sand deposited over thesediments from the alluvial plains. The sand is highly mobile due to the strong winds that rise each year before the onset of the monsoon.[17][18] Much of the bedrock is composed ofigneous andmetamorphic rocks.[1]
The geology of the region varies across its area. The oldest rocks are found in theBarmer region in the south, which arevolcanic rocks composed offelsite. In thePokhran area, there are various coloredshales, with varying hardness. Pale coloredsandstones composed primarily ofquartz are found south ofJodhpur. Sandstones withfossils belonging to theJurassic period (201.4 to 143.1 mya) are found to the east of Balmer, and to the east and north ofJaisalmer. In the Jaisalmer region, the underlying sandstone beds are covered with layers of sandstone andlimestone, which also consist of numerous fossils, and are used extensively as building materials. Towards the west and north west of Jaisalmer, a tract of dark coloured sandstone rocks withcalcium, capped by red coloured red sandstone layer, and interspersed with yellowammonite rocks.[18]
The region has adesert climate. In the summer months of April to June, average maximum temperature ranges 40–42 °C (104–108 °F) with average minimum of 23–27 °C (73–81 °F). The maximum temperature often reaches above 50 °C (122 °F) during the peak summer. In the winter months of December to February, the minimum temperature reaches −2 °C (28 °F), with average maximum of 18–24 °C (64–75 °F) with average minimum of 3.5–10 °C (38.3–50.0 °F).[1] The region receives most of the rainfall during the southwest monsoon from June to September.[1] Average annual rainfall ranges from 100–300 mm (3.9–11.8 in), and occurs during the short July-to-September southwest monsoon.[1][19] The distribution of rainfall also varies significantly across years.[1] The semi arid parts in the east have fewer sand dunes and receive slightly more precipitation.[20]
The depth of thewater table in the region varies between 10–40 m (33–131 ft), and the water is mostlybrackish.[1] The region is drained by a minor inland river system.Luni River is the longest and major river in the desert.[21] Other minor rivers that form part of the Luni river system includeBandi,Ghaggar,Guhiya,Jawai,Jojari,Liladi, andSukri rivers.[22] There are numerousendorheic salt water lakes–Sambhar,Kharaghoda,Didwana,Pachpadra, andPhalodi. These lakes accumulate water during the monsoon rains and often evaporate slowly during the dry season. The salt content of these lakes comes from the weathering of the surrounding rocks in the region.[23] The 649 km (403 mi)-longIndira Gandhi Canal, which channels water from theIndus River system, is a major source forirrigation anddrinking water.[24] Water reservoirs known as tobas,johads andtaankas are used to store rain water.[1][25][26]
Lithic tools belonging to the prehistoricAterian culture of theMaghreb from theMiddle Paleolithic era have been found in the Thar Desert.[27] TheIndus Valley Civilization flourished along the vicinity of the Ghaggar-Hakra River between 3300 BCE to 1300 BCE.[28][29] After the collapse of the Indus Valley Civilisation, which occurred around 1900 BCE, groups ofIndo-Aryan peoplesmigrated into north-western India and started to inhabit the region.[30][31] During theVedic period (1500 BCE to 500 BCE), varioustribes inhabited the region, and theKuru kingdom, the earliest Vedic state was formed by a super-tribe which joined several tribes in a new unit.[32][33] Prior to the "second urbanisation" that occurred in the Indo-Gangetic Plains, small settlements of thePainted Grey Ware culture arose in the Ghaggar-Hakra valley.[34]
By the third century BCE, a large part of the Indian subcontinent was under the control of theMauryan Empire, including portions of the desert.[35] TheKushan Empire expanded out of what is now Afghanistan into the northwest of the Indian subcontinent in the middle of the 1st century CE.[36] TheGupta Empire flourished between the 2nd and 6th centuries CE, reaching its peak in the 5th century CE, when its territory incorporated the present Thar Desert region.[37] In the eastern part of the region, theBrahmin dynasty ruled in the 7th to 8th centuries CE, which was later annexed to theUmayyad Caliphate in early 8th century CE, and theAbbasid Caliphate later.[38][39] ThePratihara dynasty ruled the eastern part of the region between the 8th and 11th centuries CE.[40]Mahmud of Ghazni annexed the region to theGhaznavid Empire in the 11th century CE.[41][42]
Expanse of Thar Desert along the India-Pakistan border
In the laterMiddle Ages, the western part of the region was ruled by severalRajput states. These states started forming in the late 7th century CE, and rose to political prominence later.[43][44][45][46] The eastern part of the region was ruled by theSoomras,[47][48][49] and theSammas from later 11th to early 16th century CE.[50][51] The period was marked by the conflict between theMughal Empire and the other dynasties that ruled the region. The conflict originated with the invasion byTimurid kingBabur, which was resisted by the Rajput states underRana Sanga.[52] The conflicts continued for over 200 years, with the initial phase remaining indecisive. The Mughals gained an upper hand between the mid 15th and late 16th centuries, while the Rajputs retook control later after the Mughal empire began to collapse in the late 16th century.[53][54] TheMarathas took control over most of the region in the 18th century CE.[55] In 19th century CE, the region came under the suzerainty of theBritish Raj, wherein it was composed of a large number ofprincely states, with powers divided amongst the local rulers and the British.[56]
Thepartition of India resulted in the formation of the independent states of India and Pakistan, and the Thar Desert region was split between the two countries. It resulted in large scale conflicts, and mass migration of people across the borders.[57][58][59] After thePolitical integration of India, andreorganisation of Indian states, majority of the eastern part of the desert became part of theRajasthan state, with minor portions inHaryana,Punjab, andGujarat.[1][4][60] The western third became part of theSindh andPunjab provinces in Pakistan.[1][4] In 1965 and 1971, further population exchanges took place in the Thar region between India and Pakistan; 3,500 people, mostly Muslims, moved from India to Pakistan, while thousands of Hindu families migrated from Pakistani to the Indian section.[61][62][63]
TheThar people are the natives of the region.[64][65] The Thar Desert is the most widely populated desert in the world, with a population density of 83 people per km2.[66] The inhabitants are composed of various religions includingHindus, andMuslims, and belong to different ethnicities.[67][68] The most spoken languages areRajasthani languages such asMarwari in central and eastern regions,Sindhi in the southwest, andLahnda in the northwest region of the Thar.[69][70]
Huts in the Thar Desert
Majority of the people live in rural nomadic communities in the harsh environment of the Thar Desert.[69] People live in small huts which are shaped like a cylindricalbee hive topped by a conical thatched roof.[71] The huts are distributed in small randomly formed clusters, while carefully planned for privacy so that the entrances of adjacent huts never face each other.[72]Middle class people in permanent settlements live in single-storeyed dwellings with large rectangular courtyards, and wideverandahs. It is supported bytimber made from local wood and plastered on the upper side with a type of clay.[73] The wood ofProsopis cineraria (khejri) provides high-quality fuel wood, and building material. Its roots also encouragenitrogen fixation, which produces higher crop yields.[74]
Water scarcity remains the major problem in the desert with dependence on temporary storage of rain water, and prolonged periods of drought.[75] Villages often consists of a few water sources such as temporary wells, and storage ponds.[71] The people spend a considerable amount of time fetching water for themselves or their animals.[76] The Thar desert region has offered suffered from poor development due to the harsh environment and access to outside world.[77]
Most of the people are involved in herding animals, limitedagriculture, and in handicrafts.[78][79][80] Agriculture happens in specifc areas supplanted by stored water, or irrigation from canals. Khadins are special crop enbankments which prevent water run off and used for agriculture. Drought resistant varieties ofgreen gram,sesame,millets,cluster beans,chickpea, andjowar are grown in the region. Shrubs likemelon,cucumber,citrus fruits, anddate palms, are grown near water bodies.[81] The Thar region is a majoropium production and consumption area.[82][83] TheThari cow breed originated fromTharparkar.[84]
TheGovernment of India initiated departmental exploration for oil in 1955 and 1956 in the area,[85] andnatural gas was discovered in 1988 in theJaisalmer basin.[86] The region is also home to severalsolar energy generation units, such as theBhadla Solar Park, with a generation capacity of over 2 gigawatts.[87]Desert safari oncamels have become increasingly popular with tourists frequenting the desert seeking adventure on camels, resulting in the development of theecotourism industry.[88]
The soil of the Thar Desert remains dry for much of the year, so it is prone towind erosion. High-velocity winds blow soil from the desert, depositing some of it on neighboring fertile lands, and causing sand dunes within the desert to shift. To counteract this problem, sand dunes are stabilised by erecting microwindbreak barriers with scrub material and then byafforestation of the treated dunes by planting the seedlings of shrubs such asCalligonum polygonoides,Cassia auriculata, andRicinus communis, and trees such asAcacia senegal,Prosopis juliflora, andAlbizzia lebbeck.[19]
"Contrary to earlier assumptions that a large glacier-fed Himalayan river, identified by some with the mythical Sarasvati, watered the Harappan heartland on the interfluve between the Indus and Ganges basins, we show that only monsoonal-fed rivers were active there during the Holocene."
"Numerous speculations have advanced the idea that the Ghaggar-Hakra fluvial system, at times identified with the lost mythical river of Sarasvati (e.g., 4, 5, 7, 19), was a large glacier fed Himalayan river. Potential sources for this river include the Yamuna River, the Sutlej River, or both rivers. However, the lack of large-scale incision on the interfluve demonstrates that large, glacier-fed rivers did not flow across the Ghaggar-Hakra region during the Holocene
"The present Ghaggar-Hakra valley and its tributary rivers are currently dry or have seasonal flows. Yet rivers were undoubtedly active in this region during the Urban Harappan Phase. We recovered sandy fluvial deposits approximately 5;400 y old at Fort Abbas in Pakistan (SI Text), and recent work (33) on the upper Ghaggar-Hakra interfluve in India also documented Holocene channel sands that are approximately 4;300 y old. On the upper interfluve, fine-grained floodplain deposition continued until the end of the Late Harappan Phase, as recent as 2,900 y ago (33) (Fig. 2B). This widespread fluvial redistribution of sediment suggests that reliable monsoon rains were able to sustain perennial rivers earlier during the Holocene and explains why Harappan settlements flourished along the entire Ghaggar-Hakra system without access to a glacier-fed river."
Valdiya (2013) dispute this, arguing that it was a large perennial river draining the high mountains as late as 3700–2500 years ago.Giosan et al. (2013) have responded to, and rejected, Valdiya's arguments.
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