How do scientists know the age of Yarrabubba crater?
Dating ancient craters is not easyThese places tend to be poorly preserved because erosion and tectonic events such as earthquakes progressively obliterate the geological past, as the researchers detail in their paper, published in the journal Nature Communications.
The team looked for evidence of “shock recrystallization” in minerals like zircon and monazite within the crater. But finding that record in minerals involved searching for microscopic grains. The uranium in the grains helped scientists determine a precise date, which coincided with the Great Ice Age.
Researchers speculate on the idea that when the meteor hit Yarrabubba, this place was covered in ice, like much of the rest of Earth at the time: “The impact fits within the context of the Earth coming out of cold conditions,” they explain.
The massive attack may have sent billions of tons of vaporized ice into the atmosphere, according to models led by the team: “On an ice sheet, the impact would have released a lot of water vapor, which is a greenhouse gas even more efficient than carbon dioxide“In the words of lead author Timmons Erickson of NASA’s Johnson Space Center and Curtin School of Earth and Planetary Sciences. “That, in turn, could cause global warming.”