- Yarrabubba crater
Yarrabubba crater refers to an
impact structure (orastrobleme ), the eroded remnant of a formerimpact crater , situated in the northernYilgarn Craton between the towns of Sandstone andMeekatharra , centralWestern Australia .Macdonald F.A., Bunting J.A. & Cina S.E. 2003. Yarrabubba—a large, deeply eroded impact structure in the Yilgarn Craton, Western Australia. Earth and Planetary Science Letters 213, 235–247. [http://dx.doi.org/10.1016/S0012-821X(03)00322-4 Abstract] ] ,Bunting J.A. & Macdonald F.A. 2004. The Yarrabubba structure, Western Australia—clues to identifying impact events in deeply eroded ancient cratons. Geological Society of Australia Abstracts 73, 227.]The original crater has been completely eroded and is not readily visible on aerial or satellite images; the evidence for impact comes rather from the presence of
shocked quartz and shatter cones in outcrops ofgranite interpreted the be near the centre of the original crater, and from geophysical data. The diameter of the original crater is uncertain, but has been estimated to be in the range 30–70 km. ] The age of the impact event is also uncertain, but it must be younger than the granite that has been shocked, which has been dated at about 2650 Ma (lateArchaean ). ] Veins ofpseudotachylite (rocks melted by friction) in the granite have given a date of 1134±26 Ma using the Ar-Ar method, and although the significance of this age is not fully clear it is currently considered by some to provide the best tentative estimate for the age.Pirajno F. 2005. Hydrothermal processes associated with meteorite impact structures: the evidence from three Australian examples and implications for economic resources. Australian Journal of Earth Sciences 52, 587–605. [http://journalsonline.tandf.co.uk/link.asp?id=gx253r5343746772 Abstract] ] TheEarth Impact Database prefers an intermediate estimate of about 2000 Ma. [http://www.unb.ca/passc/ImpactDatabase/images/yarrabubba.htm Yarrabubba] . "Earth Impact Database". Retrieved on2007-02-18 ]References
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