Major meteor craters are scattered all over Earth, however, their pasts remain a mystery.
This is about to change though: A NASA scientist and his team recently studied the age of the Yarrabubba meteor crater, which is located in Australia. They discovered that this ancient area is 2.229 billion years old, making it the world’s oldest known meteor crater.
Timmons Erickson, a research scientist with the Astromaterials Research and Exploration Science (ARES) division, along with Christopher Kirkland, Nicholas Timms, and Aaron Cavosie from Curtin University in Australia and Thomas Davison from Imperial College London, shared details on their findings in the journal Nature Communications.
The team found out that the Yarrabubba meteor crater is 200 million years older than the over 200-kilometer Vredefort Dome crater in South Africa. Dating the age of these craters could provide more information on the early days of our planet and how they impacted the environment.
2.229 billion years = the age of the Yarrabubba meteor crater ☄️ in Australia, making it the oldest currently known! A team led by a @NASA_Johnson scientist determined the age by searching for rocks that showed signs of being subjected to a meteor strike: https://t.co/EiK7pUO3ki pic.twitter.com/wgOJvOTYqa
— NASA (@NASA) January 21, 2020
“Scientists wonder how meteor impacts might relate to the formation of the continents. We also would like to know when the frequency of meteor impacts declined to the point where life could emerge and thrive,” Erickson said. “These are all big questions in the field of science.”
The Yarrabubba impact structure site is deteriorating though: NASA says its once-defining features have eroded due to natural forces. The team couldn’t use the typical approach for dating craters, so they had to think of an alternative strategy.
A picture of a zircon grain with a strange texture from the impact. (Photo Credit: NASA)
Erickson and his team searched for rocks that showed signs of exposure to a meteor strike. Rock samples that contained two minerals (monazite and zircon) were collected for analysis. These crystals consist of lead and uranium, and the ratio can be measured to determine the age of each.
An electron microscope at Curtin University was used to inspect crystals melted by the meteor impact. After measuring the lead and uranium in those crystals, the team calculated their age, which was 2.229 billion years old.
Following this discovery, ARES installed equipment for analyzing old meteor craters at its Houston-based facilities. Scientists will be able to study more ancient meteor craters and get a glimpse of Earth’s tumultuous past.
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