Bedout: A possible end-Permian impact crater offshore of Northwestern Australia

被引:139
作者
Becker, L [1 ]
Poreda, RJ
Basu, AR
Pope, KO
Harrison, TM
Nicholson, C
Iasky, R
机构
[1] Univ Calif Santa Barbara, Dept Geol Sci, Inst Crustal Studies, Santa Barbara, CA 93106 USA
[2] Univ Rochester, Dept Earth & Environm Sci, Rochester, NY 14627 USA
[3] Geo Eco Arc Res, Aquasco, MD 20608 USA
[4] Australian Natl Univ, Canberra, ACT, Australia
[5] Geol Survey Western Australia, Perth, WA 6004, Australia
关键词
D O I
10.1126/science.1093925
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
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.
引用
收藏
页码:1469 / 1476
页数:8
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