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Shoemaker impact structure
Shoemaker (formerly known as Teague Ring) is an impact structure, the deeply eroded remnant of a former impact crater, situated in arid central Western Australia, about 100 kilometres (62 mi) north-northeast of Wiluna.[1] It is named in honour of planetary geologist Eugene Shoemaker.[2] Description The prominent ring-like topographic feature, easily seen in satellite images, lies on the boundary between the Palaeoproterozoic Earaheedy Basin and the Archaean Yilgarn Craton. The area contains a number of seasonal salt lakes, the largest being Lake Teague. The first suggestion that the ring-like topographic feature may be an impact structure was published in 1974.[3] Subsequent research revealed definitive evidence for this hypothesis, including the presence of shatter cones and shocked quartz.[4][5][6] The feature has a central circular region of uplifted Archaean Granite (Teague Granite) about 12 kilometres (7.5 mi) in diameter, surrounded by a downwarped ring (ring syncline) of sedimentary rocks with an outer limit of disturbance at about 30 kilometres (19 mi) diameter, which is a minimum estimate of the size of the original crater.[5] The age of the impact event is uncertain. It must be younger than the Teague Granite in the centre, dated at 2648 ± 8 Ma (million years ago).[5] The most commonly cited age of about 1630 Ma[4] represents a re-heating event affecting the granite; while this may be the impact event it could simply be a regional tectonic event.[5] More recent dating by K–Ar methods yield ages as young as 568 ± 20 Ma,[7] this age could also date the impact event or represent tectonic activity.[5] See alsoReferences
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