- Shoemaker crater
Shoemaker (formerly known as Teague Ring) is an
impact structure (orastrobleme ), the deeply eroded remnant of a formerimpact crater , situated inarid centralWestern Australia , about 100 km north-northeast of Wiluna. It is named in honour of planetary geologistEugene Shoemaker .Pirajno F. & Glikson A.Y. 1998. Shoemaker impact structure Western Australia (formerly Teague ring structure). Celestial Mechanics and Dynamical Astronomy 69, 25–30.] The prominent ring-like topographic feature, easily seen in satellite images, lies on the boundary between thePalaeoproterozoic Earaheedy Basin and theArchaean Yilgarn Craton . The area contains a number of seasonalsalt lakes, the largest being Lake Teague.The first suggestion that the ring-like topographic feature may be an impact structure was published in 1974.Butler H. 1974. The Lake Teague ring structure, Western Australia: an astrobleme? Search 5, 536–537.] Subsequent research revealed definitive evidence for this hypothesis, including the presence of shatter cones and
shocked quartz .Bunting J.A., De Laeter J.R. & Libby W.G. 1980. Evidence for the age and cryptoexplosive origin of the Teague Ring structure, Western Australia. Geological Survey of Western Australia, Annual Review 1980, 81–85. [http://geodocs.doir.wa.gov.au/document/documentSearchCriteria.do?from=topNav&cabinetId=1101 GSWA download search] ] ,Pirajno F., Hawke P., Glikson A.Y., Haines P.W. & Uysal T. 2003. Shoemaker impact structure, Western Australia. Australian Journal of Earth Sciences 50, 775–796. [http://www.ingentaconnect.com/content/tandf/aes/2003/00000050/00000005/art00008 Abstract] ] ,Shoemaker E.M. & Shoemaker C.S. 1996. The Proterozoic impact record of Australia. AGSO Journal of Australian Geology and Geophysics 16, 379-398.] The feature has a central circular region of uplifted Archaean Granite (Teague Granite) about 12 km in diameter, surrounded by a downwarped ring (ringsyncline ) of sedimentary rocks with an outer limit of disturbance at about 30 km diameter, which is a minimum estimate of the size of the original crater. ]The age of the impact event is uncertain. It must be younger than the Teague Granite in the centre, dated at 2648 ± 8 Ma. ] The most commonly cited age of about 1630 Ma ] represents a re-heating event affecting the granite; while this may be the impact event it could simply be a regional
tectonic event. ] More recent dating by K–Ar methods yield ages as young as 568 ± 20 Ma;Pirajno F. 2002. Geology of the Shoemaker impact structure. Geological Survey of Western Australia Report 82. [http://geodocs.doir.wa.gov.au/document/documentSearchCriteria.do?from=topNav&cabinetId=1101 GSWA download search] ] , this age could also date the impact event or represent tectonic activity. ]References
External links
* [http://www.unb.ca/passc/ImpactDatabase/images/shoemaker.htm Shoemaker] at
Earth Impact Database , retrieved 27 March 2007.
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