A collective of geologists affiliated with Curtin University has unearthed compelling evidence of a hypervelocity meteoritic impact that occurred approximately 3.47 billion years ago, during the Archean Eon, within the central Pilbara region of Western Australia. Prior to this groundbreaking revelation, the oldest identified impact structure dated back 2.2 billion years, positioning this recent finding as unequivocally the most ancient impact crater ever documented on our planet.
“The Moon, possessing a rich record of over a million craters larger than 1 km in diameter, and approximately forty that exceed 100 km across, offers an exceptional chronicle of the intense bombardment experienced by inner Solar System bodies during their initial billion-year tenure,” remarked Professor Tim Johnson of Curtin University and his associates.
“Conversely, on Earth, this primordial impact record appears to have been largely effaced, a consequence of formidable erosional processes and subduction that relentlessly recycle nascent crustal material back into a convecting mantle.”
“Notwithstanding these terrestrial processes, the most venerable segments of numerous cratons – the ancient Archean nuclei (dating from 4 to 2.5 billion years ago) of continental landmasses – formed at or before 3.5 billion years ago. These should, in principle, retain vestiges of an impact flux that would have surpassed that observed in comparable lunar areas of similar age.”
“Yet, the most ancient recognized terrestrial impact formation, located at Yarrabubba in Western Australia, is dated to 2.23 billion years ago. The pressing question remains: where are the multitude of Archean craters?”
Professor Johnson and his co-authors undertook a meticulous examination of Archean rock strata at the North Pole Dome in the Pilbara region, discerning definitive indicators of a significant meteoritic impact dating back 3.5 billion years.
“This revelation has profoundly challenged prevailing assumptions regarding our planet’s deep historical trajectory,” stated Professor Johnson.
The researchers’ identification of the Archean crater was facilitated by the presence of shatter cones – unique geological formations exclusively generated by the extreme pressures associated with extraterrestrial impacts.
The specific shatter cones discovered at this locale, situated roughly 40 km west of Marble Bar, were precipitated by the cataclysmic impact of a meteoroid travelling at speeds exceeding 36,000 km/h.
This event represented a monumental geological occurrence, generating a crater in excess of 100 km in width and dispersing ejected material across the global landscape.
“Our observations of the Moon confirm that colossal impacts were a commonplace phenomenon in the nascent solar system,” articulated Professor Johnson.
“Until this juncture, the conspicuous absence of truly ancient craters meant that such features were largely overlooked by the geological community.
“This investigation furnishes a vital component for reconstructing Earth’s impact history and strongly suggests the potential for discovering numerous other ancient impact structures over time.”
“The unearthed discovery casts new illumination on the mechanisms by which meteorites influenced Earth’s primordial environmental conditions,” commented Professor Chris Kirkland of Curtin University.
“The identification of this impact event, and potentially others from the same epoch, could offer substantial insights into the origins of life, given that impact craters historically engendered environments conducive to microbial existence, such as hydrothermal pools.
“Furthermore, it substantially refines our comprehension of crustal evolution: the immense kinetic energy released by this impact may have played a pivotal role in shaping the early terrestrial crust, potentially through processes such as crustal underthrusting or by facilitating the ascent of magma from the deep Earth’s mantle towards the surface.
“It is even conceivable that this event contributed to the genesis of cratons, which are extensive, geologically stable landmasses that serve as the fundamental basis for continental formations.”
The details of this remarkable discovery are documented in a publication featured in the esteemed journal Nature Communications.
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C.L. Kirkland et al. 2025. A Paleoarchaean impact crater in the Pilbara Craton, Western Australia. Nat Commun 16, 2224; doi: 10.1038/s41467-025-57558-3
