The sky in Australia
Scientists were unable, earlier, to determine the age of the impact crater in Yaruba, which is about 70 km in diameter due to the erosion of its original structure, but it was considered one of the oldest craters on the planet.
Thanks to a highly accurate technique, the researchers succeeded in targeting metal pellets that “recorded” the shock from the impact, via a recrystallization path.
The study, published in the journal Nature Communications, concluded that the impact crater in Yarubaoba was formed 2.229 billion years ago, a date coinciding with the end of the freezing phase called “Earth Snowball”.
“There is geological evidence other than that related to the study that is based on the existence of clusters and volumes on Earth between 2.4 billion and 2.2 billion years ago, and the newest clusters are in South Africa,” said Timmons Erickson, of the Johnson Center at NASA, the lead author of the study. Omar parallels the impact crater in Yarubaoba.
“It is interesting to note that the conglomerates of ice have been absent in this place from the memory of minerals for nearly 400 million years after the impact,” said Christopher Kirkland, who is also one of the authors of the study, “although nothing proves that there is a bound volume in the impact zone.”
The researchers thus presented the hypothesis that an asteroid struck a frozen region and violated a layer of ice with a thickness of 5 km and then tossed into the atmosphere a huge amount of water vapor, up to 500 billion tons.
And these volumes of water vapor, a greenhouse gas that is stronger than carbon dioxide, led to a warming that helped the planet out of this ice age.
This scenario is phenomenal, as most asteroid impact craters have been associated with a global decrease in temperature, and the most famous example is the asteroid that struck Yucatan in Mexico and ended the domination of dinosaurs about 66 million years ago.