Scientists confirm world’s oldest meteorite impact crater in Western Australia’s Pilbara region
Consensus Summary
Scientists from Curtin University have confirmed that the North Pole Dome crater in Western Australia’s Pilbara region is the world’s oldest known meteorite impact site, dating back approximately 3 billion years. This discovery surpasses the previous record held by the Yarrabubba crater, which is 2.2 billion years old. The age was determined using two independent methods: analyzing zircon crystals with skeletal shapes and apatite mineral growth, both reset by the impact event. The study, published in *Geology*, highlights the rarity of such well-preserved geological evidence from Earth’s early history, offering insights into the violent processes that shaped the planet during the Archean eon. However, some experts, including Harvard’s Alec Brenner, dispute the findings, arguing that the zircon evidence could stem from non-impact hydrothermal events and that nearby shatter cones suggest the impact must be younger than 2.77 billion years. Despite the controversy, the researchers maintain their conclusions, emphasizing the significance of the discovery as a 'smoking gun' for the ancient event.
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Key details reported by multiple sources:
- The North Pole Dome crater in Western Australia’s Pilbara region is dated to approximately 3 billion years old, making it the world’s oldest known meteorite impact site.
- The age of the North Pole Dome crater was determined using zircon crystals with skeletal shapes and apatite mineral growth, both reset by the impact event.
- The previous record holder for the oldest impact crater was Yarrabubba in Western Australia, dated at 2.2 billion years old.
- The study was published in the journal *Geology* and led by Prof. Chris Kirkland from Curtin University’s Timescales of Mineral Systems Group.
- The North Pole Dome crater is located in the East Pilbara region, about 1,600 kilometers north of Perth.
- The meteorite strike occurred during the Archean eon (4 to 2.5 billion years ago), a period when tectonic plates were forming and early life (stromatolites) existed.
Points of Difference
Details reported by only one source:
- The study used an Australian-designed instrument called the Sensitive High-Resolution Ion MicroProbe (SHRIMP) to measure zircon crystal ages.
- The article describes Earth as a 'water world' with few continental crust pieces at the time of the impact, with a dimmer sun and a closer moon.
- Associate Professor Bruce Schaefer from Macquarie University called the findings a 'detective story' and noted that the combination of zircon and apatite evidence is the 'smoking gun'.
- The article mentions that the North Pole Dome crater’s rocks are 'deep time capsules' offering a rare glimpse into early Earth’s violent processes.
- The North Pole Dome crater’s age was initially disputed last year, with another group of scientists debunking the claim a month later, leading to a second study.
- Harvard University postdoctoral fellow Alec Brenner disputed the findings, arguing the zircon evidence could result from non-impact hydrothermal events and that shatter cones in nearby 2.77-billion-year-old rocks suggest the impact must be younger than that.
- The ABC article includes a quote from Brenner stating: 'Seeing an unknown fluid flow event does not mean it resulted from an impact.'
- The article notes that the North Pole Dome crater is 750 million years older than the previous record holder, Yarrabubba.
Contradictions
Conflicting information between sources:
- The Guardian states the North Pole Dome crater is older than Yarrabubba (2.2 billion years), while the ABC notes that the previous record was 2.2 to 2.3 billion years for Yarrabubba, creating a slight discrepancy in the exact age range of Yarrabubba.
- The ABC reports that Harvard’s Alec Brenner disputes the North Pole Dome’s age, citing shatter cones in 2.77-billion-year-old rocks as evidence the impact must be younger, while the Guardian does not mention this specific counter-evidence.
- The Guardian describes the zircon crystals as 'little lightning bolts' with skeletal patterns, while the ABC refers to them as having 'unusual branching, skeletal shapes,' with no direct contradiction but differing phrasing.
Source Articles
Scientists find ‘smoking gun’ evidence of world’s oldest meteorite strike in Western Australia
Curtin University researchers use innovative techniques to date three-billion-year-old impact crater in Pilbara region A meteorite that struck Earth three billion years ago left behind a “smoking gun” – evidence of the world’s oldest impact crater in a remote part of Australia. Ancient rocks in Western Australia’s Pilbara region record the event, which occurred during the Archean eon, a period 4 to 2.5 billion years ago, when tectonic plates were beginning to form and early life emerging. Contin
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