Researchers have found the oldest meteorite impact crater on Earth in the Pilbara region of Western Australia. This crater is over 3.5 billion years old, making it more than a billion years older than any previously known craters.
This exciting discovery, published in Nature Communications, supports a theory about how Earth’s first continents were formed.
Geologists believe that the earliest rocks, which are more than 3 billion years old, helped shape important chemical and biological processes on our planet. However, there’s still debate over how these ancient rocks came to be. Some think they emerged from hot materials rising from Earth’s core, while others argue they were formed through plate tectonics like we see today.
Our team proposes that the energy needed to create these early continents in the Pilbara came from outside Earth, specifically through collisions with massive meteorites. These impacts could have released huge amounts of energy, melting rocks and creating volcanic “blobs” that eventually formed continental crust.
To find the crater, we traveled north from Perth in May 2021 and worked alongside partners from the Geological Survey of Western Australia (GSWA). Our initial target was a unique rock layer called the Antarctic Creek Member, which is surrounded by older basaltic lava. This layer contains spherules—small drops formed from molten rock thrown up during impacts. However, those spherules could have come from anywhere on Earth, as many impact craters have since eroded away.
Thanks to maps and aerial photography, we pinpointed a spot in Pilbara and began our search. Excitedly, we spread out to explore the area, and when we regrouped an hour later, we were thrilled to share that we had all discovered shatter cones. These delicate structures form only through meteorite impacts and are the visible signs of such events.
In a short time, we realized we were standing on the floor of a massive ancient impact crater. After some quick photos and samples, we had to move on but were determined to return. The crucial question remained: how old were these shatter cones, and had we indeed found the oldest crater on Earth?
Upon further research, we confirmed that we had. Returning to the site in May 2024, we spent ten days examining the area more thoroughly. We found shatter cones throughout the Antarctic Creek Member and traced them over several kilometers. The evidence showed that the impact must be as old as the rocks themselves, dating back 3.5 billion years.
This discovery not only set the record for the oldest impact crater on Earth but also supported our ideas about the role of meteorite impacts in shaping our planet’s surface. Aside from the Nyamal people, who have lived in the area for thousands of years, no other geologists had likely seen these features since they formed.
Our findings suggest that meteorite impacts have played a significant role in the geological history of Earth, similar to their effects on the Moon and other celestial bodies. The search for more ancient craters could lead to groundbreaking insights into the early Earth and the development of life itself.
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