Ramgarh crater

Ramgarh crater, also known as Ramgarh structure, Ramgarh Dome and Ramgarh astrobleme,[1] is a meteor impact crater of 3.5 kilometres (2.2 mi) diameter in Kota plateau of Vindhya range located adjacent to Ramgarh village in Mangrol tehsil of Baran district in Rajasthan state of India.[1] When formally accepted as the third crater in India, its diameter size would be between the two already confirmed craters in India - Dhala in Madhya Pradesh with 14 km diameter and Lonar in Buldhana district of Maharashtra with 1.8 km diameter.[2][3][4][5]

The Ramgarh Crater as seen from an aeroplane

It is designated as a National Geological Monument.[6] The Bhand Deva Temple, a 10th-century Shiva temple in the style of the Khajuraho Group of Monuments, is located near the centre of the crater. Kuno National Park, 50-60 km away, is accessible by multiple entry points via minor roads or NH6. Crater lies 110 km from Kota, 250 from Jaipur and 500 km from Delhi.

Scientific studies

The crater is yet to be fully investigated in a systematic way.[7] In 1869, crater was first visited by geologist Frederick Richard Mallet[8] of Geological Survey of India (GSI).[7] Rai Bahadur Kishan Singh Rawat (1850-1921), a colonial era Indian explorer and cartographer, was first to map it on a small scale (1 : 63,360).[9][10] Other studies include by those of Arthur Lennox Coulson (1927–28), Sharma and Singh and Jaganathan and Rao (1969–70), Crowford (1972),[11] Rakshit (1973), Ramaswamy (1981), Vimal Kumar Reddy(1984) etc.[1] A rootless mass of sheared sandstone found near Bandewara temple in the crater indicates a fall back material.[1] Crawford,[11] after discovering shatter coned colluvium in the middle of the crater, was first to suggest that this was an impact crater.[7] Auden suggested that the crater in upper Vindhya Range might be kimberlite intrusion similar to Majhgawan kimberlite intrusion.[7] In 1960, Geological Society of London recognised it as an impact crater.[2] In addition, the Ramgarh crater is already among the confirmed/proven list of impact craters[12][13][14] based on three-step confidence level criteria of Anna Mikheeva of Russian Academy of Sciences (1 for probable, 2 for potential, 3 for questionable),[15] applied to the impact sites that have appeared several times in the literature and/or have been endorsed by the Impact Field Studies Group (IFSG)[16] and/or Expert Database on Earth Impact Structures (EDEIS).[17]

The Earth Impact Database (EID), at the University of New Brunswick in Canada,[18] is used as the most authoritative for confirming the impact craters.[19] The confirmation of Ramgrah being impact crater from EID is pending. In January 2018 Professor Vinod Agrawal and Geologists Pushpendra Singh Ranawat, members of team composed of GSI, INTACH and Mohanlal Sukhadia University, which visited the crater to collect samples for the scientific study of the genesis of the crater, said the several types of evidence at crater meets the established criteria for the meteorite impact and that is a very rare site in India of multi-faceted significance including geological heritage.[2] Team stated that the ample research on the site has been conducted to gather geochemical and other evidence published in peer reviewed journals, hence once the evidence is accepted by the national and global approving entities in India and Canada respectively the crater will be likely recognised as 191th impact crater in the world and 3rd in India by 2020 by the Earth Impact Database.[20][2]

Geology
See also: Geology of Vindhya Range

Topography

Located on a 240m MSL high plateau, the 3.2 kilometres (2.0 mi) diameter Ramgarh ring crater rise further 150 to 200 m above the surrounding plateau. Located in Vindhya Range it is part of Bhander Group of Vindhyan Supergroup it has a raised rim and a circular depression in its centre forming a plain with average elevation of 260 m above sea level.

Hydrology

Ramgarh rivulet flows from the south-west chasm of the crater and it becomes a tributary of Parvati river 4 km in the west. There are several other gullies (deeper channel and ditches cut into rocks and soil by the erosive action of fast flowing forceful water) and rills (shallow channel cut into soil by the erosive action of flowing water) formed with radial (flowing out of crater) and centripetal (flowing in to crater) drainage. Radial streams flow into the Parbati River, a tributary of Chambal River,[21][22]

Mineralogy

Glass resembling rock samples were collected and investigated. These spherules contain very high percentage of iron, along with very high ratios of nickel and cobalt. This high ratios suggests a meteorite strike or extraterrestrial rocks.[3]

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See also

References
  1. GSI. "The curious ring structure of Ramgarh in Vindhyas of Rajastan". Geological Survey of India. Geological Survey of India. Archived from the original on 3 February 2016. Retrieved 27 July 2015.
  2. Ramgarh crater caused by meteorite impact, claim experts, Economic Times, 9 January 2019.
  3. Misra, S; G. Lashkari; D. Panda; A. Dube; M. S. Sisodia; H. E. Newsom; D. Sengupta (2008). "Geochemical Evidence for the Meteorite Impact Origin of Ramgarh Structure, India" (PDF). Lunar and Planetary Science XXXIX. Houston, Texas: Lunar and Planetary Institute. Retrieved 2009-08-25.
  4. Misra, S; A. Dube; P. K. Srivastava; H. E. Newsow (2008). "Time of Formation of Ramgarh Crater, India – Constraints from Geological Structures" (PDF). Lunar and Planetary Science XXXIX. Houston, Texas: Lunar and Planetary Institute. Retrieved 2009-08-25.
  5. Sisodia, M.S; G. Lashkari; N.Bhandari (2006). "Impact Origin Of the Ramgarh Structure, Rajasthan : Some New Evidences". Journal of the Geological Society of India vol 67 pp 423–431. Retrieved 2011-07-06.
  6. "Ramgarh, Zawar accepted as geo-heritage sites in Rajasthan". The Times of India. Retrieved 2018-09-14.
  7. BALASUNDARAM, M., DUBE, A. Ramgarh, 1973, "Structure, India", Nature (journal), 242, 40 doi:10.1038/242040a0.
  8. Mallet, F. R., 1869, Memoir, Geological Survey of India, vol 7, page 129.
  9. Kenneth Mason, 1923, "Kishen Singh and the Indian Explorers", The Geographical Journal, Vol. LXII-July to December.
  10. Derek J. Waller, 2004, "The Pundits: British Exploration of Tibet and Central Asia," University Press of Kentucky.
  11. Crawford, A. R., 1972, Nature (journal), 237, 96.
  12. Ramgarh
  13. Nayak V.K. (1997). The circular structure at Ramgarh, India: an astrobleme(?). LPI Contrib., No.922, P. 31
  14. Master S., Pandit M.K. (1999). New evidence for an impact origin of the Ramgarh structure, Rajasthan, India . Meteorit. and Planet. Sci., Vol.34, No.4, P. 79
  16. Impact Field Studies Group
  17. Expert Database on Earth Impact Structures
  18. "Earth Impact Database". University of New Brunswick. Retrieved 1 April 2019.
  19. Earth Impact Database
  20. "Rajasthan's Crater Mystery Finally Solved? Scientists Point to Meteorite Impact". News18. Retrieved 2018-09-14.
  21. Pratiyogita Darpan, August, 2007; p. 268
  22. Ram Narayan Yadava (2003). Water resources system operation: proceedings of the International Conference on Water and Environment (WE-2003), December 15-18, 2003, Bhopal, India. Allied Publishers. pp. 545–546. ISBN 978-81-7764-548-4. Retrieved 1 May 2011.

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