Killer Meteor Impact in Earth's Past
August 11th 2007 02:59
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A group of scientists have found evidence of a mega meteor impact crater much larger and earlier than the one that killed the dinosaurs an impact that they believe caused the biggest mass extinction in Earth's history.
The 480 Kilometers-wide crater lies hidden more than a Kilometer beneath the East Antarctic Ice Shelf. Satellite data confirming gravity measurements that reveal its existence suggest that it could date back about 250 million years when almost all animal life on Earth died out.
Approximately 100 million years ago, Australia split from the ancient Gondwana supercontinent and began drifting north, pushed away by the expansion of a rift valley into the eastern Indian Ocean. The rift cuts directly through the crater, so the impact may have helped the rift to form.
I am not entirely convinced this was the case although the hypothesis is sound.
Scientists believe that the Permian-Triassic extinction paved the way for the dinosaurs to rise to prominence. The Wilkes Land crater is more than twice the size of the Chicxulub crater in the Yucatan peninsula, which marks the impact that may have devastated the dinosaurs 65 million years ago. The Chicxulub meteor ( Mexico) is thought to have been 9km wide, while the Wilkes Land meteor could have been up to 48Km wide - four or five times wider.
"This Wilkes Land impact is much bigger than the impact that killed the dinosaurs, and probably would have caused catastrophic damage at the time,"
The Wilkes Land region is located on East Antarctic ice shelf, south of Australia.
According to Ralph von Frese, a professor of geological sciences at Ohio State University.
The scientists used gravity fluctuations measured by NASA's GRACE satellites to peer beneath Antarctica's icy surface, and found a 200-mile-wide plug of mantle material a mass concentration in geological varience that had risen up into the Earth's crust. The crater formation is to yet confirmed rock and core samples need to taken which makes the process of drilling a kilometer deep a very costly exercise.
Images by Ohio State University
The 480 Kilometers-wide crater lies hidden more than a Kilometer beneath the East Antarctic Ice Shelf. Satellite data confirming gravity measurements that reveal its existence suggest that it could date back about 250 million years when almost all animal life on Earth died out.
Approximately 100 million years ago, Australia split from the ancient Gondwana supercontinent and began drifting north, pushed away by the expansion of a rift valley into the eastern Indian Ocean. The rift cuts directly through the crater, so the impact may have helped the rift to form.
Satellite image showing bed rock topography
Scientists believe that the Permian-Triassic extinction paved the way for the dinosaurs to rise to prominence. The Wilkes Land crater is more than twice the size of the Chicxulub crater in the Yucatan peninsula, which marks the impact that may have devastated the dinosaurs 65 million years ago. The Chicxulub meteor ( Mexico) is thought to have been 9km wide, while the Wilkes Land meteor could have been up to 48Km wide - four or five times wider.
Gravity signal
The Wilkes Land region is located on East Antarctic ice shelf, south of Australia.
According to Ralph von Frese, a professor of geological sciences at Ohio State University.
The scientists used gravity fluctuations measured by NASA's GRACE satellites to peer beneath Antarctica's icy surface, and found a 200-mile-wide plug of mantle material a mass concentration in geological varience that had risen up into the Earth's crust. The crater formation is to yet confirmed rock and core samples need to taken which makes the process of drilling a kilometer deep a very costly exercise.
Image showing Earth's crust thickness
Images by Ohio State University
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