title: Bedout: a possible end-Permian impact crater offshore of northwestern Australia.
abstract: The Bedout High, located on the northwestern continental margin of Australia, has emerged as a prime candidate for an end-Permian impact structure. Seismic imaging, gravity data, and the identification of melt rocks and impact breccias from drill cores located on top of Bedout are consistent with the presence of a buried impact crater. The impact breccias contain nearly pure silica glass (SiO2), fractured and shock-melted plagioclases, and spherulitic glass. The distribution of glass and shocked minerals over hundreds of meters of core material implies that a melt sheet is present. Available gravity and seismic data suggest that the Bedout High represents the central uplift of a crater similar in size to Chicxulub. A plagioclase separate from the Lagrange-1 exploration well has an Ar/Ar age of 250.1 +/- 4.5 million years. The location, size, and age of the Bedout crater can account for reported occurrences of impact debris in Permian-Triassic boundary sediments worldwide.
authors.affiliation: Institute for Crustal Studies, Department of Geological Sciences, University of California, Santa Barbara, CA 93106, USA. lbecker@crustal.ucsb.edu
authors.forename: L
authors.initials: L
authors.lastname: Becker
authors.forename: R J
authors.initials: RJ
authors.lastname: Poreda
authors.forename: A R
authors.initials: AR
authors.lastname: Basu
authors.forename: K O
authors.initials: KO
authors.lastname: Pope
authors.forename: T M
authors.initials: TM
authors.lastname: Harrison
authors.forename: C
authors.initials: C
authors.lastname: Nicholson
authors.forename: R
authors.initials: R
authors.lastname: Iasky
mesh_terms: D001128:Argon; D001315:Australia; D003460:Crystallization; D005843:Geography; D019015:Geologic Sediments; D005898:Glass; D019110:Meteoroids; D008903:Minerals; D011868:Radioisotopes; D012822:Silicon Dioxide
chemical_list: D008903:Minerals; D011868:Radioisotopes; D001128:Argon; D012822:Silicon Dioxide