Avi Blizovsky
Gravity Measurement System and Radar Data Reveal Deep Crater Under Ice - Imaging - Ohio State University
What appears to be a crater 480 kilometers in diameter has been discovered beneath the East Antarctic Ice Shelf. The scientists who discovered the crater say that it was created by a massive meteorite about 250 million years ago.
The configuration in the area known as Wilkes Land was discovered by NASA satellites that map the tiny differences in the rate of gravity around the Earth.
The damage to Wilkes Land is much greater than the one that wiped out the dinosaurs, said Prof. Ralph von Perez from Ohio State University.
If the crater really did form at the time von Vries and his colleagues believe, it raises an interesting possibility as the source of the "Great Dying" - the largest mass extinction in Earth's history - when 95% of all sea creatures and 70% of all terrestrial species disappeared. Rocks from that period are now located in China, Italy and Pakistan. Some of the scientists have suspected for a long time that the extinction at the border between the Permian and Tyrian periods (PT) could have happened very quickly - as a result of an environmental change caused by the impact of a huge rock from space.
The main suspects include fluctuations in sea level, volcanic activity, impact from space, and the melting of methane ice in ocean sediments.
A similar argument is now considered the cause of the much later extinction of the dinosaurs, 65 million years ago.
A geological structure known as Bedout High on the sea floor near what is now known as Australia has also been suggested as the remains of the possible crater from the PT impact, however the impact theory is still not accepted by all scientists.
The common theory is that several factors, including extensive volcanic activity and global warming that have combined over thousands of years have undermined biodiversity. "The Earth was probably hit by objects from space, but it is unlikely that they were the fatal factors, argue the opponents.
The Ohio team's research used slight fluctuations in Earth's gravity measurements as received from several NASA GRACE series satellites to dig beneath the ice sheet covering the Antarctic continent. The team also included researchers from the USA, Russia and Korea. The information about the crater was presented for the first time at the general meeting of the American Geophysical Union in Baltimore.
They knew cosmic collisions
For news at the BBC
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