Shiva crater

The Shiva Crater is a geologic structure, which is hypothesized by Sankar Chatterjee[1] and colleagues to be a 500-kilometre (310 mi) diameter impact structure. This geologic structure consists of the Bombay High and Surat Depression. They lie beneath the Indian continental shelf and the Arabian Sea west of Mumbai, India. Chatterjee named this structure after Shiva, the Hindu god of destruction and renewal.[1][2] It is presently (2019) on the list of probable impact craters[3] and is rated '1' based on three-step confidence level criteria of Anna Mikheeva of Russian Academy of Sciences (0 for proven, 1 for probable, 2 for potential, 3 for questionable and 4 for discredited),[4] 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)[5] and/or Expert Database on Earth Impact Structures (EDEIS).[6] [note 1]

Shiva crater
Location of the crater offshore India
Impact crater/structure
Diameter500 km (310 mi)
Age~66 million years
Cretaceous–Paleogene boundary
ExposedNo
DrilledNo
Location
LocationMumbai Offshore Basin
Coordinates18°40′N 70°14′E
CountryIndia

Arguments

Chatterjee argues that the Shiva Crater was formed around 65 million years ago, about the same time as a number of other impact craters and the Cretaceous–Paleogene extinction event (Cretaceous–Paleogene boundary / K-Pg boundary). Although the site has shifted since its formation because of sea floor spreading, the formation is approximately 600 kilometres (370 miles) long by 400 km (250 mi) wide. It is estimated that this proposed crater would have been made by an asteroid or comet approximately 40 km (25 mi) in diameter.[1][2]

At the time of the Cretaceous–Paleogene extinction, India was located over the Réunion hotspot of the Indian Ocean. Hot material rising from the mantle flooded portions of India with a vast amount of lava, creating a plateau known as the Deccan Traps. It has been hypothesized that either the crater or the Deccan Traps associated with the area are the reason for the high level of oil and natural gas reserves in the region.[8]

Geology and morphology

Unlike typical known extraterrestrial impact structures, Shiva is teardrop shaped, roughly 600 km × 400 km (370 mi × 250 mi). It is also unusually rectangular. Chatterjee argues that the low angle of an impact combined with boundary fault lines and unstable rock led to this unusual formation.[2] The age of the structure is inferred from the Deccan Traps which overlie part of it.[2]

Shiva and mass extinction
Main article: Cretaceous–Paleogene extinction event

The proposed Shiva Crater and other possible impact craters along with the Chicxulub have led to the hypothesis that multiple impacts caused the massive extinction event at the end of the Cretaceous period. Chatterjee is confident that Shiva was one of many impacts, stating that "the K-T extinction was definitely a multiple-impact scenario."[9] Other theories have argued that since the Chicxulub impact is believed by some researchers to have occurred earlier than the extinction of the non-avian dinosaurs, Shiva's impact was enough to cause the mass extinction by itself.[10] Evidence published in a 2013 Science article by Paul R. Renne at the University of California at Berkeley suggests that the Chicxulub crater is in fact within the time frame of when the mass extinction occurred.[11]

See also
Impact craters in India
Other related topics

Notes
  1. Wikipedia uses the Earth Impact Database (EID) as the most authoritative at for confirming the craters;[7] however, as of 22 December 2019, confirmation of the Shiva crater has not been added to the EID.

References
  1. Chatterjee, S. (1997). "'Multiple impacts at the KT boundary and the death of the dinosaurs". Comparative Planetology, Geological Education, History of Geology: Proceedings of the 30th International Geological Congress, Beijing, China, 4–14 August 1996. VSP. pp. 31–54. ISBN 978-90-6764-254-5.
  2. Chatterjee, S., N. Guven, A. Yoshinobu, and R. Donofrio. (2006) Shiva Structure: a possible KT boundary impact crater on the western shelf of India. Museum of Texas Tech University Special Publications. 50, 39pp.
  3. Shiva
  5. Impact Field Studies Group
  6. Expert Database on Earth Impact Structures
  7. Earth Impact Database
  8. Agrawal, P., Pandey, O. (November 2000). "Thermal regime, hydrocarbon maturation and geodynamic events along the western margin of India since late Cretaceous". Journal of Geodynamics. 30 (4): 439–459. Bibcode:2000JGeo...30..439P. doi:10.1016/S0264-3707(00)00002-8.CS1 maint: multiple names: authors list (link)
  9. Rampino, M. R., and B. M. Haggerty (1996) The “Shiva Hypothesis”: Impacts, mass extinctions, and the galaxy. Earth, Moon, and Planets. 72(1–3):441–460.
  10. Davis, J. W. (2006) archived copy of Texas Tech Paleontologist Finds Evidence That Meteorite Strike Near Bombay May Have Wiped Out Dinosaurs. Texas Tech Today, Texas Tech University, Lubbock, Texas.
  11. Renne, Paul (8 February 2013). "Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary" (PDF). Science. 339 (6120): 684–7. Bibcode:2013Sci...339..684R. doi:10.1126/science.1230492. PMID 23393261.
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