SYDNEY, March 6 (Xinhua) -- Australian scientists have identified the oldest known meteorite impact crater on Earth, a discovery that could greatly reshape the understanding of the planet's formation and the origins of life.
The discovery significantly challenged previous assumptions about Earth's ancient history, the study's co-lead author Tim Johnson from Curtin University said on Thursday.
Curtin University researchers investigated rock layers in the North Pole Dome, an area of the Pilbara region of Western Australia (WA), and found evidence of a major meteorite impact 3.5 billion years ago.
"Before our discovery, the oldest impact crater was 2.2 billion years old, so this is by far the oldest known crater ever found on Earth," Johnson said.
Researchers identified the crater through the presence of shatter cones, unique rock formations created under the extreme pressure of a meteorite impact. These formations, found about 40 km west of Marble Bar in WA's Pilbara region, were formed when a meteorite struck the area at over 36,000 km per hour.
This would have been a major planetary event, resulting in a crater more than 100 km wide that would have sent debris flying across the globe, according to the study published in Nature Communications, conducted by a team from Curtin's School of Earth and Planetary Sciences and the Geological Survey of Western Australia.
Johnson explained that observations of the Moon indicate large impacts were common in the early solar system. However, he noted that the lack of any truly ancient craters on Earth has led geologists to largely overlook their significance.
"This study provides a crucial piece of the puzzle of Earth's impact history and suggests there may be many other ancient craters that could be discovered over time," he said.
Co-lead author Chris Kirkland from Curtin University said the discovery provides new insights into the role of meteorite impacts in shaping Earth's early environment, adding uncovering this impact, along with others from the same era, could help explain how life began, as impact craters created conditions favorable for microbial life, such as hot water pools. ■
