Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia
Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia
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DOI：
10.1126/science.1093925
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发表时间：
2004-06
期刊：
影响因子：
56.9
通讯作者：
L. Becker;R. Poreda;A. Basu;K. Pope;T. Harrison;C. Nicholson;R. Iasky
中科院分区：
文献类型：
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作者：
L. Becker;R. Poreda;A. Basu;K. Pope;T. Harrison;C. Nicholson;R. Iasky
位于澳大利亚西北部大陆边缘的Bedout High已成为二叠纪末撞击构造的主要候选者。地震成像、重力数据以及从位于Bedout顶部的岩芯中识别出的熔融岩石和撞击角砾岩与埋藏的撞击坑的存在一致。冲击角砾岩含有几乎纯的二氧化硅玻璃（SiO2），破碎和冲击熔融斜长石，和球晶玻璃。在数百米的核心材料的玻璃和冲击矿物的分布意味着熔融片的存在。现有的重力和地震数据表明，Bedout High代表了一个与希克苏鲁布大小相似的陨石坑的中央隆起。从拉格朗日-1勘探井中分离出的斜长石的Ar/Ar年龄为250.1 ± 4.5百万年。Bedout陨石坑的位置、大小和年龄可以解释世界各地二叠纪-三叠纪边界沉积物中所报告的撞击碎片的出现。
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.