Dec 28, 2016 07:19 PM
(This post was last modified: Dec 28, 2016 07:32 PM by Yazata.)
Wilkes Land, a part of Antarctica, is the site of the Wilkes Land Anomaly. This is a gravity anomaly roughly 300 miles across (480km), surrounded by circular geological structure visible to radar exploration of the Earth's surface under the Antarctic ice.
https://en.wikipedia.org/wiki/Wilkes_Land_crater
Buried under thick Antarctic ice, nobody is exactly sure what it is. The best guess is that it's a huge ancient impact crater. (Other hypotheses are that it's a volcanic-style mantle plume.) Various lines of evidence suggest that it's less than 500 million years old, hence it happened after the Cambrian explosion and the appearance of multicellular life.
If it is an impact crater, it's much larger than the Chicxulub impact in Yucatan that is hypothesized to have caused the mass-extinction that killed off the dinosaurs. (Up to 2.5x as big.)
Speculation is that it might be associated with the Permian-Triassic Extinction Event, the largest of the several mass-extinctions that have been noted in the fossil record. This one is so big that it's been dubbed 'The Great Dying', where up to 96% of marine species suddenly disappeared along with some 70% of land vertebrates. It happened before the appearance of the dinosaurs, some 250 million years ago.
https://en.wikipedia.org/wiki/Permian%E2...tion_event
There's also speculation that this impact might have weakened the Earth's crust, contributing to the Godwana continent breaking in two, forming Antarctica and Australia.
All of this is controversial though, and critics argue that an absence of ejecta suggest that the Great Dying wasn't the result of an asteroid impact at all. (That's the actual process of science in all of it's rather messy glory, as alternative hypotheses contend.)
https://en.wikipedia.org/wiki/Wilkes_Land_crater
Buried under thick Antarctic ice, nobody is exactly sure what it is. The best guess is that it's a huge ancient impact crater. (Other hypotheses are that it's a volcanic-style mantle plume.) Various lines of evidence suggest that it's less than 500 million years old, hence it happened after the Cambrian explosion and the appearance of multicellular life.
If it is an impact crater, it's much larger than the Chicxulub impact in Yucatan that is hypothesized to have caused the mass-extinction that killed off the dinosaurs. (Up to 2.5x as big.)
Speculation is that it might be associated with the Permian-Triassic Extinction Event, the largest of the several mass-extinctions that have been noted in the fossil record. This one is so big that it's been dubbed 'The Great Dying', where up to 96% of marine species suddenly disappeared along with some 70% of land vertebrates. It happened before the appearance of the dinosaurs, some 250 million years ago.
https://en.wikipedia.org/wiki/Permian%E2...tion_event
There's also speculation that this impact might have weakened the Earth's crust, contributing to the Godwana continent breaking in two, forming Antarctica and Australia.
All of this is controversial though, and critics argue that an absence of ejecta suggest that the Great Dying wasn't the result of an asteroid impact at all. (That's the actual process of science in all of it's rather messy glory, as alternative hypotheses contend.)
