Earth has gone through many changes in its 4.5-billion-year history, and Snowball Earth is one of the stages. The dramatic episode appeared between 700 million and 600 million years ago when ice smothered the entire planet, from the poles to the equator. Scientists have recently revealed some new reports regarding the oldest known impact crater on Earth that can tell us how our planet emerged from a long-ago frozen phase.
According to the scientists, a 43-mile wide crater in Western Australia outback may have formed 2 billion years ago after an asteroid slammed into the Earth. The world’s oldest known impact site, Yarrabubba Crater, may have occurred just when our planet started coming out of a “Snowball Earth '' period.
The surface of the Earth is constantly changing as it is geologically active. Additionally, the active tectonic plates and erosion process makes it difficult to determine the oldest impact craters. Many get buried when crustal plates dive beneath each other, and most others are worn away by water and wind over the ages.
The researchers recognized the age of the crater by analyzing the minerals present in it. The lead author of the study Timmon Erickson and his colleagues examined tiny pieces of Yarrabubba's shocked rock. Nicholas Timms, a co-author of the study, said in a statement, "The age of the Yarrabubba impact matches the demise of a series of ancient glaciations."
"After the impact, glacial deposits are absent in the rock record for 400 million years."
"This twist of fate suggests that the large meteorite impact may have influenced global climate," he added.
To understand the methods in which the asteroid may have changed the Earth's climate, the researchers carried out different simulations. The study further reveals, "Calculations indicated that an impact into an ice-covered continent could have sent half a trillion tons of water vapor -- an important greenhouse gas -- into the atmosphere. This finding raises the question whether this impact may have tipped the scales enough to end glacial conditions."
After getting exploded into the ice-covered continent, the impact could have released up to half a trillion of water vapor into the atmosphere, an important greenhouse gas that may have played a role in changing Earth’s climate, the study reveals.
Experts believe the asteroid strike is responsible for the extinction of the dinosaurs 66 million years ago. It also led to global ocean cooling and widespread acid rain. The findings raise questions of whether all older impact craters have been eroded or they are still there waiting to be discovered.