Precise radiometric age establishes Yarrabubba, Western Australia, as Earth's oldest recognised meteorite impact structure.,Nature Communications

当前位置： X-MOL 学术 › Nat. Commun. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Precise radiometric age establishes Yarrabubba, Western Australia, as Earth's oldest recognised meteorite impact structure.
Nature Communications ( IF 14.7 ) Pub Date : 2020-01-21 , DOI: 10.1038/s41467-019-13985-7
Timmons M Erickson _{1,

2,

3} , Christopher L Kirkland ₄ , Nicholas E Timms ₂ , Aaron J Cavosie ₂ , Thomas M Davison ₅

Affiliation

The ~70 km-diameter Yarrabubba impact structure in Western Australia is regarded as among Earth's oldest, but has hitherto lacked precise age constraints. Here we present U-Pb ages for impact-driven shock-recrystallised accessory minerals. Shock-recrystallised monazite yields a precise impact age of 2229 ± 5 Ma, coeval with shock-reset zircon. This result establishes Yarrabubba as the oldest recognised meteorite impact structure on Earth, extending the terrestrial cratering record back >200 million years. The age of Yarrabubba coincides, within uncertainty, with temporal constraint for the youngest Palaeoproterozoic glacial deposits, the Rietfontein diamictite in South Africa. Numerical impact simulations indicate that a 70 km-diameter crater into a continental glacier could release between 8.7 × 1013 to 5.0 × 1015 kg of H2O vapour instantaneously into the atmosphere. These results provide new estimates of impact-produced H2O vapour abundances for models investigating termination of the Paleoproterozoic glaciations, and highlight the possible role of impact cratering in modifying Earth's climate.

中文翻译：

精确的辐射年龄使西澳大利亚州的亚拉布巴成为地球上公认的最古老的陨石撞击结构。

西澳大利亚州直径约70公里的Yarrabubba撞击结构被认为是地球上最古老的撞击结构，但迄今缺乏精确的年龄限制。在这里，我们介绍了冲击驱动的冲击重结晶的辅助矿物的U-Pb年龄。冲击重结晶的独居石产生的精确冲击年龄为2229±5 Ma，与冲击复位锆石相当。这一结果使Yarrabubba成为地球上公认的最古老的陨石撞击结构，将陆地陨石坑记录扩展了超过2亿年。Yarrabubba的年龄在不确定的情况下与南非最早的元古生代冰川沉积物Rietfontein钙钛矿的时间限制相吻合。数值撞击模拟表明，进入大陆冰川的直径70公里的火山口可能释放8.7×1013至5。立即将0×1015 kg的H2O蒸气排入大气。这些结果为研究古元古代冰川终止的模型提供了影响产生的H2O蒸气丰度的新估计，并强调了影响陨石坑在改变地球气候中的可能作用。

更新日期：2020-01-22

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11