Calvin crater

{{Short description|Impact crater in the US}}

{{Infobox terrestrial impact site

| name = Calvin crater

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| map = Michigan

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| location = Calvin Township, Michigan

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| coordinates = {{coord|41.83|-85.95}}

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| confidence = Confirmed

| diameter = {{convert|8.5|km}}

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| age = 450 ± 10 Ma

| exposed = No

| drilled = Yes

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| country = US

| state = Michigan

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Calvin is an impact crater located in Calvin Township, Cass County, in the U.S. state of Michigan. It was discovered in 1987 by Randall Milstein of the Michigan Geological Survey while examining data from about 100 test wells drilled in the area.{{cite web | date = September 12, 1994 | url = http://www.umich.edu/~urecord/9495/Sep12_94/23.htm | title = Craters are evidence of ancient meteorite strikes | publisher = The University Record | accessdate = May 26, 2006 | archive-date = June 6, 2007 | archive-url = https://web.archive.org/web/20070606122044/http://www.umich.edu/~urecord/9495/Sep12_94/23.htm | url-status = dead }}

It is {{convert|8.5|km}} in diameter and the age is estimated to be 450 ± 10 million years (Ordovician).{{cite Earth Impact DB | name = Calvin | accessdate = 2009-08-12}} The crater is not exposed to the surface. It lies about 100 to 400 feet (30–120 m) below today's ground level.