The Aravali Range in Rajasthan
|Peak||Guru Shikhar, Mount Abu|
|Elevation||1,722 m (5,650 ft)|
|Length||692 km (430 mi)|
|Pronunciation||Hindi pronunciation: [ aa ra vli]|
|States||Rajasthan, Haryana, Delhi and Gujarat|
|Region||North India, Western India|
|Settlement||Delhi, Gurgaon, Mount Abu|
|Rivers||Banas, Luni, Sakhi and Sabarmati|
|Age of rock||Precambrian|
|Type of rock||Fold mountains from Plate tectonics|
The Aravalli Range (Devanagari, also spelled Aravali range, is a range of mountains running approximately 692 km (430 mi) in a southwest direction, starting in North India from Delhi and passing through southern Haryana, through to Western India across the states of Rajasthan and ending in Gujarat.Mount Abu is the highest peak in the mountain range at 5650 feet.
The Aravalli Range, an eroded stub of ancient mountains, is the oldest range of fold mountains in India. The natural history of the Aravalli Range dates back to times when the Indian Plate was separated from the Eurasian Plate by an ocean. The Proterozoic Aravalli-Delhi orogenic belt in northwest India is similar to the younger Himalayan-type orogenic belts of the Mesozoic-Cenozoic era (of the Phanerozoic) in terms of component parts and appears to have passed through a near-orderly Wilson supercontinental cycle of events. The range rose in a Precambrian event called the Aravalli-Delhi Orogen. The Aravalli Range is a northeast-southwest trending orogenic belt that is located in the northwestern part of Indian Peninsula. It is part of the Indian Shield that was formed from a series of cratonic collisions. In ancient times, Aravalli were extremely high but since have worn down almost completely by millions of years of weathering, whereas the Himalayas being young fold mountains are still continuously rising. Aravalli, being the old fold mountains, have stopped growing higher due to the cessation of upward thrust caused by the stopping of movement of the tectonic plates in the Earth's crust below them. The Aravalli Range joins two of the ancient earth's crust segments that make up the greater Indian craton, the Aravalli Craton which is the Marwar segment of earth's crust to the northwest of the Aravalli Range, and the Bundelkand Craton segment of earth's crust to the southeast of the Aravalli Range. Cratons, generally found in the interiors of tectonic plates, are old and stable parts of the continental lithosphere that has remained relatively undeformed during the cycles of merging and rifting of continents.
It consists of two main sequences formed in Proterozoic eon, metasedimentary rock (sedimentary rocks metamorphised under pressure and heat without melting) and metavolcanic rock (metamorphised volcanic rocks) sequences of the Aravalli Supergroup and Delhi Supergroup. These two supergroups rest over the Archean Bhilwara Gneissic Complex basement, which is a gneissic (high-grade metamorphism of sedimentary or igneous rocks) basement formed during the archean eon 4 Ga ago. It started as an inverted basin, that rifted and pulled apart into granitoid basement, initially during Aravalli passive rifting around 2.5 to 2.0 Ga years ago and then during Delhi active rifting around 1.9 to 1.6 Ga years ago. It started with rifting of a rigid Archaean continent banded gneissic complex around 2.2 Ga with the coexisting formation of the Bhilwara aulacogen in its eastern part and eventual rupturing and separation of the continent along a line parallel to the Rakhabdev (Rishabhdev) lineament to the west, simultaneous development of a passive continental margin with the undersea shelf rise sediments of the Aravalli-Jharol belts depositing on the attenuated crust on the eastern flank of the separated continent, subsequent destruction of the continental margin by accretion of the Delhi island arc (a type of archipelago composed of an arc-shaped chain of volcanoes closely situated parallel to a convergent boundary between two converging tectonic plates) from the west around 1.5 Ga. This tectonic plates collision event involved early thrusting with partial obduction (overthrusting of oceanic lithosphere onto continental lithosphere at a convergent plate boundary) of the oceanic crust along the Rakhabdev lineament, flattening and eventual wrenching (also called strike-slip plate fault, sideways horizontal movement of colliding plates with no vertical motion) parallel to the collision zone. Associated mafic igneous rocks show both continental and oceanic tholeiitic geochemistry (magnesium and iron-rich igneous rocks) from phanerozoic eon (541-0 million) with rift-related magmatic rock formations.
The Aravalli-Delhi Orogen is an orogen event that led to a large structural deformation of the Earth's lithosphere (crust and uppermost mantle, such as Aravalli and Himalayas fold mountains) due to the interaction between tectonic plates when a continental plate is crumpled and is pushed upwards to form mountain ranges, and involve a great range of geological processes collectively called orogenesis.
The archean basement had served as a rigid indentor which controlled the overall wedge shaped geometry of the orogen. Lithology of area shows that the base rocks of Aravalli are of Mewar Gneiss formed by high-grade regional metamorphic processes from preexisting formations that were originally sedimentary rock with earliest life form that were formed during the archean eon, these contain fossils of unicellular organism such as green algae and cyanobacteria in stromatolitic carbonate ocean reefs formed during the paleoproterozoic era. Sedimentary exhalative deposits of base metal sulfide ores formed extensively along several, long, linear zones in the Bhilwara aulacogen or produced local concentration in the rifted Aravalli continental margin, where rich stromatolitic phosphorites also formed. Tectonic evolution of the Aravalli Mountains shows Mewar Geniss rocks are overlain by Delhi Supergroup type of rocks that also have post-Aravalli intrusions. Metal sulfide ores were formed in two different epochs, lead and zinc sulfide ores were formed in the sedimentary rocks around 1.8 Ga years ago during Paleoproterozoic phase. The tectonic setting of Zinc-lead-copper sulfides mineralisation in Delhi supergroup rocks in Haryana-Delhi were formed in mantle plume volcanic action around 1 Ga years ago covering Haryana and Rajasthan during mesoproterozoic. In the southern part of Aravalli supergroup arc base metal sulfides were generated near the subduction zone on the western fringe and in zones of back-arc extension to the south-east. Continued subduction produced W-Sn (Tungsten-Tin) mineralisation in S-type (sedimentary unmetamorphosed rock) felsic (volcanic rock) plutons (underground crystallised solidified magma). This includes commercially viable quantities of minerals, such as rock phosphate, lead-zinc-silver mineral deposits at Zawar, Rikahbdev serpentinite, talc and pyrophyllite) and asbestos, apatite, kyanite and beryl.
Mining of copper and other metals in the Aravalli range dates back to at least the 5th century BCE, based on carbon dating. Recent research indicates that copper was already mined here during the Sothi-Siswal period going back to c. 4000 BCE. Ancient Kalibangan and Kunal, Haryana settlements obtained copper here.
The Indian Craton includes five major cratons. Cratons are part of continental crust made up of upper layer called platforms and older bottom layer called basement rocks. sheilds are part of a craton where basement rock crops out at the surface and it is the relatively oldest and most stable part that are undeformed by the plate tectonics. The Aravalli Craton (Marwar-Mewar Craton or Western Indian Craton) covers Rajasthan as well as western and southern Haryana. It includes the Mewar Craton in the east and Marwar Craton in the west. It is limited by the Great Boundary Fault in the east, the Thar desert in the west, Indo-ganetic alluvium in the north, and the Son River-Narmada River-Tapti River basins in the south. It mainly has quartzite, marble, pelite, greywacke and extinct volcanos exposed in the Aravalli-Delhi Orogen. Malani Igneous Suite is the largest in India and third largest igneous suit in the world. The uniqueness of the geological feature of Malani Igneous Suite at Jodhpur prompted the Geological Survey of India to declare the site as a National Geological Monument.
Tatctonic-stratigraphic evolution of the Aravalli Range:
The Stratigraphic classification Aravalli Range can be divided into the following parts (north to south direction):
The Aravalli Range has been site of three broad stages of human history, early stone age saw the use of flint stones; mid-stone age starting from 20,000 BP saw the domestication of cattle for agriculture; and post stone age starting from 10,000 BP saw the development of the Kalibangan civilisation, 4,000 years old Aahar civilisation and 2,800 years old Gneshwar civilisation, Aarayan civilisation and Vedic era civilisations.
Tosham hills have several Indus Valley Civilization sites in and around this hill range as the area falls under copper-bearing zone of Southwest Haryana & Northeast Rajasthan of Aravalli hill range. Investigation of IVC network of mineral ore needs for the metallurgical work and trade shows that most common type of grinding stone at Harappa is of Delhi quartzite type found only in the westernmost outliers of the Aravalli range in southern Haryana near Kaliana and Makanwas villages of Bhiwani district has bears red-pink to pinkish grey colour, crisscrossed with thin haematite and quartz filled fractures in sugary size grain texture.
Ravindra Singh and Dheerendra Singh of Banaras Hindu University, in association with Cambridge University, carried out ASI-financed excavations of Indus Valley Civilization site at the ground of Government School in Khanak, during September 2014 and Feb-May 2016. They found early to mature Harappan phase IVC materials, pottery, semiprecious beads of lapis lazuli, carnelian and others. They also found evidence of matallurgical activities, such as crucible (used for pouring molten metal), furnace lining, burnt floor, ash and ore slugs. Ceramic petrography, Metallography, Scanning electron microscope (SEM, non-destructive, surface images of nanoscale resolution), Energy-dispersive X-ray spectroscopy (EDXA and EDXMA, trade name EDAX, non-destructive, qualitative and quantitative elemental composition) and Transmission electron microscopy (TEM, destructive method) scientific studies of the material found prove that the Khanak site was inhabited by the IVC metal-workers who used the locally mined polymetalic tin, and they were also familiar with metallurgical work with copper and bronze. Since excavation did not reach natural soil, it is believed that finds at Khanak site might go as far back as pre-Harappan era to Sothi-Siswal culture (4600 BCE or 6600 BP).
Ganeshwar sunari Cultural Complex (GSCC) is a collection of third millennium BC settlements in the area of the Aravalli Hill Range. Among them, there are similarities in material culture, and in the production of copper tools. They are located near the copper mines.
"The GSCC is east of the Harappan culture, to the north-east of Ahar-Banas Complex, north/north west to the Kayatha Culture and at a later date, west of the OCP-Copper Hoard sites (Ochre Coloured Pottery culture-Copper Hoard Culture). Located within the regions of the Aravalli Hill Range, primarily along the Kantli, Sabi, Sota, Dohan and Bondi rivers, the GJCC is the largest copper producing community in third millennium BC South Asia, with 385 sites documented. Archaeological indicators of the GSCC were documented primarily in Jaipur, Jhunjhunu, and Sikar districts of Rajasthan, India ..."
Among their pottery, we find the incised ware, and reserved slipware.
The Northern Aravalli range in Delhi and Haryana has humid subtropical climate and hot semi-arid climate continental climate with very hot summers and relatively cool winters. The main characteristics of climate in Hisar are dryness, extremes of temperature, and scanty rainfall. The maximum daytime temperature during the summer varies between 40 and 46 °C (104 and 115 °F). During winter, its ranges between 1.5 and 4 °C.
The Central Aravalli range in Rajasthan has an arid and dry climate.
The Sariska-Delhi leopard wildlife corridor or the Northern Aravalli leopard wildlife corridor is a 200 km long important biodiversity and wildlife corridor which runs from the Sariska Tiger Reserve in Rajasthan to Delhi Ridge.
This corridor is an important habitat for the Indian leopards and jackals of Aravalli. In January 2019, the Wildlife Institute of India announced that they will undertake the survey of leopard and wildlife, using pugmarks and trap cameras, subsequently, leopards and jackals will be tracked via the radio collars. Urban development, especially the highways and railways bisecting the Aravalli range and wildlife corridor in several places pose a great risk. Large parts of Aravalli are legally and physically unprotected, with no wildlife passages and little or no wildlife conservation work resulting in deaths of over 10 leopards in 4 years between January 2015 to January 2019.
The Haryana side of the Gurugram-Faridabad Aravalli hill forests lack availability of water due to which wild animals are seldom seen there. The Government of Haryana used drones for aerial surveys and dug 22 ephemeral pits in 2018 to store the rainwater which became dry during the summer months. In January 2019, the government announced the plan to make the pit perennial by connecting those with pipelines from the nearby villages.
Human activity, such as unplanned urbanisation and polluting plants, also pose a great threat. There is often reluctance and denial on part of the government officials of the presence of wildlife such as leopard so that the forest land can be exploited and opened up for the intrusive human development.
This corridor runs from Sariska and Ranthmbor to Gujarat.
The following national parks, wildlife reserves, and forests lie in the Aravalli Range.
The Aravalli Range has several forests with a diversity of environment.
The Aravalli Range is rich in wildlife. The first-ever 2017 wildlife survey of a 200 square kilometre area crossing five districts (Gurgaon, Faridabad, Mewat, Rewari and Mahendergarh) of Haryana by the Wildlife Institute of India (WII) found 14 species, including leopards, striped hyena (7 sightings), golden jackal (9 sightings, with 92% occupancy across the survey area), nilgai (55 sightings), palm civet (7 sightings), wild pig (14 sightings), rhesus macaque (55 sightings), peafowl (57 sightings) and Indian crested porcupine (12 sightings). Encouraged by the first survey, the wildlife department has prepared a plan for a comprehensive study and census of wildlife across the whole Aravalli Range, including radio collar tracking of the wild animals. Well known leopard and hyena habitat is along the Ferozpure Jhirka-Nuh Aravali range as well as Delhi South Ridge (Faridabad-Gurugram) to Farrukhnagar area on the Delhi-Haryana border, with reports of sightings in Saidpur, Lokri and Jhund Sarai Viran villages near the KMP expressway; Bhukarka 7 km from Pataudi; Pathkori, Bhond, Mandawar in Ferozepur Jirka region.
In May 1992, some parts of the Aravalli hills in Rajasthan and Haryana were protected from mining through the Ecologically Sensitive Areas clauses of Indian laws. In 2003, the central government of India prohibited mining operations in these areas. In 2004, India's Supreme Court banned mining in the notified areas of Aravalli Range. In May 2009, the Supreme Court extended the ban on mining in an area of 448 km2 across the Faridabad, Gurgaon and Mewat districts in Haryana, covering the Aravalli Range.
A 2013 report used high-resolution Cartosat-1 & LISS-IV satellite imaging to determine the existence and condition of mines in the Aravalli Range. In the Guru Gram district, the Aravalli hills occupy an area of 11,256 hectares, of which 491 (4.36%) hectares had mines, of which 16 hectares (0.14%) were abandoned flooded mines. In the Faridabad and Mewat districts, about 3610 hectares were part of mining industry, out of a total of 49,300 hectares. These mines were primarily granite and marble quarries for India's residential and real estate construction applications. In the Central Rajasthan region, Sharma states that the presence of some mining has had both positive and negative effects on neighbouring agriculture and the ecosystem. The rain-induced erosion brings nutrients as well as potential contaminants.
The Aravali Range is the source area of many rivers, resulting in development of human settlements with sustainable economy since pre-historic times. The Delhi Mumbai Industrial Corridor Project, Western Dedicated Freight Corridor, Mumbai-Ahmedabad high-speed rail corridor, North Western Railway network, Jaipur-Kishangarh Expressway and Delhi-Jaipur Expressway, all run parallel to the length of the Aravalli Range providing an economic boost.
Aravali range is the home of several forests, wildlife, and protected areas, UNESCO heritage listed forts, hundreds of rivers and ancient history to sustain a large tourism industry.
Damage to the environment and ecology from the unorganised urbanisation, overexploitation of the natural resources including water and minerals, mining, untreated human waste and disposal, pollution, loss of forest cover and wildlife habitat, unprotected status of most of the Aravalli and the lack of an integrated Aravalli management agency are the major causes of concern. Bad implementation of ban on mining in Aravali hills. Current government is more responsible for this scenario.
Sunset from the sunset point of Mount Abu