Kirkland Christopher L, Johnson Tim E, Kaempf Jonas, Ribeiro Bruno V, Zametzer Andreas, Smithies R Hugh, McDonald Brad
Curtin Frontier Institute for Geoscience Solutions, Timescales of Mineral Systems Group, School of Earth and Planetary Sciences, Curtin University, Perth, WA, Australia.
Geological Survey of Western Australia, Department of Mines, Industry Regulation and Safety, 100 Plain Street, East Perth, WA, Australia.
Nat Commun. 2025 Mar 6;16(1):2224. doi: 10.1038/s41467-025-57558-3.
The role of meteorite impacts in the origin, modification, and destruction of crust during the first two billion years of Earth history (4.5-2.5 billion years ago; Ga) is disputed. Whereas some argue for a relatively minor contribution overall, others have proposed that individual giant impactors (>10-50 km diameter) can initiate subduction zones and deep mantle plumes, arguably triggering a chain of events that formed cratons, the ancient nuclei of the continents. The uncertainty is compounded by the seeming absence of impact structures older than 2.23 Ga, such that the evidence for the terrestrial impact flux in the Hadean and Archaean eons is circumstantial. Here, we report the discovery of shatter cones in a complex, dominantly metasedimentary layer, the Antarctic Creek Member (ACM), in the centre of the East Pilbara Terrane, Western Australia, which provide unequivocal evidence for a hypervelocity meteorite impact. The shocked rocks of the crater floor are overlain by (unshocked) carbonate breccias and pillow lavas, stratigraphically constraining the age of the impact to 3.47 Ga and confirming discovery of the only Archaean crater known thus far.
在地球历史的前20亿年（45亿至25亿年前；Ga）中，陨石撞击在地壳的起源、改造和破坏过程中所起的作用存在争议。一些人认为总体贡献相对较小，而另一些人则提出，个别巨型撞击体（直径>10 - 50千米）能够引发俯冲带和深部地幔柱，这可以说是引发了一系列形成克拉通（大陆古老核心）的事件。由于似乎不存在年龄超过22.3亿年的撞击构造，使得冥古宙和太古宙时期地球撞击通量的证据只是间接的，这进一步加剧了不确定性。在此，我们报告在西澳大利亚皮尔巴拉地块东部中心一个复杂的、以变质沉积岩为主的层位——南极溪组（ACM）中发现了震裂锥，这为超高速陨石撞击提供了明确证据。撞击坑底部的冲击岩石被（未冲击的）碳酸盐角砾岩和枕状熔岩覆盖，从地层学上确定撞击年龄为34.7亿年，并证实发现了迄今为止已知的唯一太古宙撞击坑。
