Skip to comments.Oldest known impact crater found
Posted on 07/08/2012 11:37:26 PM PDT by rjbemsha
A 100 kilometre-wide crater has been found in Greenland, the result of a massive asteroid or comet impact a billion years before any other known collision on Earth.
(Excerpt) Read more at cardiff.ac.uk ...
I didn’t realize Greenland had that much “old” surface. There’s not much crust left that’s over 1 billion years old.
At least, that hasn’t been extensively remodeled at some point.
Over the 3 billion years since the impact, the land has been eroded down to expose deeper crust 25 km below the original surface. All external parts of the impact structure have been removed, but the effects of the intense impact shock wave penetrated deep into the crust - far deeper than at any other known crater - and these remain visible.Just... WOW!
Hey better watch out, that is where the “Thing” is, don’t thaw him out.
Finding the evidence was made all the harder because there is no obvious bowl-shaped crater left to find. Over the 3 billion years since the impact, the land has been eroded down to expose deeper crust 25 km below the original surface. All external parts of the impact structure have been removed, but the effects of the intense impact shock wave penetrated deep into the crust - far deeper than at any other known crater - and these remain visible.
However, because the effects of impact at these depths have never been observed before it has taken nearly three years of painstaking work to assemble all the key evidence. (The team was...) left with a giant impact as the only explanation for all of the facts."
Only around 180 impact craters have ever been discovered on Earth and around 30% of them contain important natural resources of minerals or oil and gas. The largest and oldest known crater prior to this study, the 300 kilometre wide Vredefort crater in South Africa, is 2 billion years in age and heavily eroded.
Dr McDonald added that "It has taken us nearly three years to convince our peers in the scientific community of this but the mining industry was far more receptive. A Canadian exploration company has been using the impact model to explore for deposits of nickel and platinum metals at Maniitsoq since the autumn of 2011."
I thought the 450-km diameter Hudson Bay’s Nastapoka Arc crater on the East side of Hudson’s Bay was the biggest.
Horrible! This precious crater should be preserved for all eternity in its natural state for the enjoyment of all. Hands off the crater! Stop the mining company exploitation!
When an impact crater is 3 billion years old, does that mean that it’s too old to be Bush’s fault?
Is this visible now because there has been more melting of the ice or did people just not recognize it before?
Used to be there were no craters on the Earth, because of erosion. IOW, no one bothered to look for them, and when they were pointed out or obvious as hell, they were characterized either as erosional features (like the Carolina Bays still are by some people) or as “cryptovolcanic” (as the Barringer Meteor Crater was). Nearly 200 have been identified, mostly large like the Manicougan structure.