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Introduction - changed "It is presently (2019)" to "As of 2019" using "As of" template

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{{Infobox terrestrial impact site
| name = Shiva crater
| other_name =
| photo =
| photo_size =
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| map = India
| map_alt =
| map_caption = Location of the crater offshore India
| map_size =
| location = [[Mumbai]] Offshore Basin
| label =
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| coordinates = {{coord|18|40|N|70|14|E|type:landmark_region:IN_scale:10000000|display=inline,title}}
| coordinates_ref =
| confidence =
| diameter = {{convert|500|km|mi|abbr=on}}
| depth =
| rise =
| imp_size =
| age = ~66 million years<br>[[Cretaceous–Paleogene boundary]]
| exposed = No
| drilled = No
| bolide =
| translation =
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| country = [[India]]
| state =
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}}

The '''Shiva Crater''' is a geologic structure, which is hypothesized by [[Sankar Chatterjee]]<ref name="chatterjee 1997">{{cite book|last=Chatterjee|first=S.|title=Comparative Planetology, Geological Education, History of Geology: Proceedings of the 30th International Geological Congress, Beijing, China, 4–14 August 1996|chapter-url=https://books.google.com/books?id=3IORF1Ei3LIC&pg=PA31|year=1997|publisher=VSP|isbn=978-90-6764-254-5|pages=31–54|chapter='Multiple impacts at the KT boundary and the death of the dinosaurs}}</ref> and colleagues to be a {{convert|500|km|mi|adj=on}} diameter asteroid 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 [[Hinduism|Hindu]] god of destruction and renewal.<ref name="chatterjee 1997"/><ref name="chatterjee 5">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.</ref> {{As of|2019}}, it is on the [[List of possible impact structures on Earth|list of probable impact craters]]<ref>[http://labmpg.sscc.ru/a633.html Shiva]</ref> 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),<ref name=Mikheeva>* {{cite LSA |last=Mikheeva |first=Anna |year=2019 |title=The Complete Catalog of the Earth's Impact structures |url=http://labmpg.sscc.ru/index1.html |publisher=Institute of Computational Mathematics and Mathematical Geophysics SB RAS |pages=1 |access-date=2019-04-02}}, 2017</ref> 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)<ref>[http://impacts.rajmon.cz/ Impact Field Studies Group]</ref> and/or Expert Database on Earth Impact Structures (EDEIS).<ref>[http://tsun.sscc.ru/nh/edeis.html Expert Database on Earth Impact Structures]</ref>
{{refn|group=note|name=EID|Wikipedia uses the [[Earth Impact Database]] (EID) as the most authoritative at for confirming the craters;<ref>[http://www.passc.net/EarthImpactDatabase/index.html Earth Impact Database]</ref> however, as of 22 December 2019, confirmation of the Shiva crater has not been added to the EID.}}

== 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 {{convert|600|km|abbr=off}} long by {{convert|400|km|abbr=on}} wide. If its status as an impact crater is ever confirmed, the Shiva crater would be the largest-known impact crater on Earth. It is estimated that this proposed crater would have been made by an [[asteroid]] or [[comet]] approximately {{convert|40|km|abbr=on}} in diameter.<ref name="chatterjee 1997"/><ref name="chatterjee 5"/>

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 (geology)|mantle]] flooded portions of India with a vast amount of [[flood basalt|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.<ref>{{cite journal |author=Agrawal, P., Pandey, O. |date=November 2000 |title= Thermal regime, hydrocarbon maturation and geodynamic events along the western margin of India since late Cretaceous|journal= Journal of Geodynamics|volume= 30|issue=4 |pages=439–459 |doi= 10.1016/S0264-3707(00)00002-8 |bibcode = 2000JGeo...30..439P }}</ref>

=== Geology and morphology ===
Unlike typical known extraterrestrial impact structures, Shiva is teardrop shaped, roughly {{convert|600|x|400|km|abbr=on}}. 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.<ref name="chatterjee 5"/> The age of the structure is inferred from the [[Deccan Traps]] which overlie part of it.<ref name="chatterjee 5"/>

=== Shiva and mass extinction ===
{{Main|Cretaceous–Paleogene extinction event}}
The proposed Shiva Crater and other possible impact craters along with the [[Chicxulub crater|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."<ref name= Rampino>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.</ref> 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.<ref name="Davis2004a">Davis, J. W. (2006)
[https://web.archive.org/web/20070505021703/http://www.depts.ttu.edu/communications/news/stories/06-11-dinosaur.php archived copy] of [http://www.depts.ttu.edu/communications/news/stories/06-11-dinosaur.php ''Texas Tech Paleontologist Finds Evidence That Meteorite Strike Near Bombay May Have Wiped Out Dinosaurs.''] Texas Tech Today, Texas Tech University, Lubbock, Texas.</ref> Evidence published in a 2013 ''[[Science (journal)|Science]]'' article by [[Paul Renne|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.<ref>{{cite journal|last1=Renne|first1=Paul|url=https://eps.harvard.edu/files/eps/files/renne.kt_.science.2013.pdf|title=Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary|journal=Science|date=8 February 2013|volume=339|issue=6120|pages=684–7|bibcode=2013Sci...339..684R|doi=10.1126/science.1230492|pmid=23393261}}</ref>

== See also ==
{{Portal|Astronomy|India}}

; Impact craters in India
* [[Lonar lake|Lonar crater]] at [[Lonar]] in [[Buldhana district]] of Maharashtra
* [[Luna crater]] at [[Kutch district]] of Gujarat
* [[Ramgarh crater|Ramgarh Crater]] in [[Mangrol, Rajasthan|Mangrol]] tehsil of [[Baran district]] of Rajasthan
* Shiva crater, an undersea super crater west of India

; Other related topics
* [[List of impact craters on Earth]]
* [[List of possible impact structures on Earth]]

==Notes==
{{Reflist|group=note}}

== References ==
{{Reflist}}

== External links ==
* [http://gsa.confex.com/gsa/2003AM/finalprogram/abstract_58126.htm The Shiva Crater: Implications for Deccan Volcanism, India-seychelles Rifting, Dinosaur Extinction, and Petroleum Entrapment at the Kt Boundary] by Chatterjee, Sankar; Guven, Necip; Yoshinobu, Aaaron; and Donofrio, Richard; Paper No. 60-8, 2003 Seattle Annual Meeting of Geological Society of America (November 2–5, 2003).
* [http://www.spacedaily.com/news/deepimpact-04r.html Deep Impact - Shiva: Another K-T Impact?] by Leslie Mullen for Astrobiology Magazine (Nov. 2004).
* [http://labmpg.sscc.ru/impact/index1.html The Complete Catalog of the Earth's Impact structures]
* [http://www.depts.ttu.edu/gesc/Fac_pages/Yoshinobu/Published_pdfs/Chatterjee%20et%20al.%202006.pdf Shiva Structure: A Possible KT Boundary Impact Crater on the Western Shelf of India]

{{KT boundary}}
{{Impact cratering on Earth}}
{{Authority control}}

[[Category:Impact craters of India]]
[[Category:Possible impact craters on Earth]]
[[Category:Cretaceous impact craters]]
[[Category:Geology of the Indian Ocean]]

Shiva crater - Revision history

imported>GeoWriter: Introduction - changed "It is presently (2019)" to "As of 2019" using "As of" template