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Strangways is a large impact structure, the eroded remnant of a former impact crater, situated in the Northern Territory, Australia. It was named after the nearby Strangways River. The location is remote and difficult to access. The circular topographic feature that marks the site was originally thought to be volcanic, with an impact origin first proposed in 1971 after the discovery of evidence diagnostic of impact including shatter cones and shocked quartz.〔 〕 The circular topographic feature is about in diameter and lies within Mesoproterozoic sedimentary rocks of the McArthur Basin. However, this is only a relic of the original crater after considerable erosion. Estimates of the original rim diameter vary between different researchers in the range ;〔 (Abstract ) 〕 the Earth Impact Database〔 prefers a diameter of . The age of the impact event has been determined at 646 ± 42 Ma (Neoproterozoic) based on radiometric dating of impact melt rocks.〔 (Abstract ) 〕 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Strangways crater」の詳細全文を読む スポンサード リンク
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