Impact crater 19 miles wide found beneath Greenland glacier
Source: Guardian
Ian Sample Science editor
@iansample
Wed 14 Nov 2018 14.00 EST
A huge impact crater has been discovered under a half-mile-thick Greenland ice sheet.
The enormous bowl-shaped dent appears to be the result of a mile-wide iron meteorite slamming into the island at a speed of 12 miles per second as recently as 12,000 years ago.
The impact of the 10bn-tonne space rock would have unleashed 47m times the energy of the Little Boy nuclear bomb dropped on Hiroshima in 1945. It would have melted vast amounts of ice, sending freshwater rushing into the oceans, and blasted rocky debris high into the atmosphere.
At 19.3 miles wide, the crater ranks among the 25 largest known on Earth and is the first to be found beneath an ice sheet.
Read more: https://www.theguardian.com/science/2018/nov/14/impact-crater-19-miles-wide-found-beneath-greenland-glacier
Honeycombe8
(37,648 posts)I wonder what the effect of that throughout the world would have been.
PoliticAverse
(26,366 posts)Honeycombe8
(37,648 posts)Was early man around 12,000 years ago? I think so, right? But that's too recent for the big event that killed the dinosaurs.
Fascinating.
PoliticAverse
(26,366 posts)Honeycombe8
(37,648 posts)I'm going to have to read up on this tonight. Maybe find some documentaries on my Roku.
lagomorph777
(30,613 posts)12k years ago was just around the end of the most recent Ice Age (and the end of the Pleistocene era). The beginning of the thaw was delayed a bit by a glitch ( the "Younger Dryas" ) in the temperature curve; this impact might explain the glitch. On the plot below, note a warm spell about 15k - 13k years ago, then a sudden cold spell, then a resumption of the warming.
https://www.donsmaps.com/endoficeage.html
Notice this is around the same time that the very oldest known megalithic construction (or any substantial stone construction anywhere in the world) appears. The moment it became physically possible, humans started building things. Note: this site predates the Great Pyramids by 5,500 years! It also predates the invention of fired pottery, and the wheel.
http://gobeklitepe.info/
Boomer
(4,167 posts)Modern humans discovered agriculture somewhere around 12-14,000 years ago, at the start of the current interglacial. So this is practically yesterday for our species.
For the previous 30-40,000 years we were hunter-gatherers.
noneof_theabove
(410 posts)as the "great flood" spoken about in every religion on the planet
JKV does not have monopoly on that.
lagomorph777
(30,613 posts)Ferretherder
(1,445 posts)...a couple of million years ago, according to some paleo-anthropologists. Actually, I haven't kept all that up to date on the most recent findings and studies, but our species has been plugging along for a 'while', now!
pecosbob
(7,533 posts)12000 years ago the effects of the event would likely have been witnessed by 'modern' humans.
Sunlei
(22,651 posts)Honeycombe8
(37,648 posts)I'll have to look & see what was going on 12k yrs ago.
DFW
(54,272 posts)And he was ready to testify to the Senate Judiciary Committee what he was doing when the meteor struck. He had the notes with him while he was testifying.
Honeycombe8
(37,648 posts)Mustellus
(328 posts)under the antartic ice sheet.
https://www.space.com/2452-giant-crater-tied-worst-mass-extinction.html
padfun
(1,786 posts)It marked the extinction of most large animals in the NA continent and the extinction of the mammoths and sabertooths.
It lasted until about 11400 years ago, about 1500 years in total. Sea Level increased almost 400 ft from the time the glaciers were at maximum, about 20,000 years ago.
Lucky Luciano
(11,248 posts)Quixote1818
(28,918 posts)Last edited Wed Nov 14, 2018, 09:18 PM - Edit history (1)
None of the other explanations were very solid. However, the article says 3 million to 12,000 years ago so we need to wait and see exactly when it occurred. 12,000 years ago is unlikely
Beausoleil
(2,835 posts)herding cats
(19,558 posts)Quixote1818
(28,918 posts)The exact timing of the asteroid strike, however, is fairly vague, with the researchers saying it happened between 3 million and 12,000 years ago. But preliminary evidence suggests it happened relatively recently.
https://gizmodo.com/a-massive-impact-crater-has-been-detected-beneath-green-1830437095
We will have to wait and see if 12,000 years ago ends up the correct date. If so that would make a lot of sense.
herding cats
(19,558 posts)A comet of that size, at that time, could have been the cause. As has been speculated before.
Brother Buzz
(36,364 posts)The Inuit people discovered deposits of other iron meteorites in that region, and learned to work it using stone tools. Because of limited fuel, they learned to work the iron cold, and used the valuable fire only to relieve stresses to reduce cracking.
https://www.ancient-origins.net/news-history-archaeology/people-arctic-worked-meteorite-iron-1200-years-ago-002573
Honeycombe8
(37,648 posts)they learned to work iron meteorites using stone tools? Interesting.
Brother Buzz
(36,364 posts)Basalt made decent bashing devices.
Honeycombe8
(37,648 posts)BlancheSplanchnik
(20,219 posts)Funny coincidence!
The book is Magicians of the Gods by Graham Hancock. Im listening to the audio book, read by himself. Its good!
RandiFan1290
(6,221 posts)Quixote1818
(28,918 posts)Either that or he has done too many drugs. https://www.scientificamerican.com/article/no-there-wasnt-an-advanced-civilization-12-000-years-ago/
He also wasn't the first to propose a meteor caused the extinctions: Second, Hancock's impact hypothesis comes from scientists who first proposed it in 2007 as an explanation for the North American megafaunal extinction around that time and has been the subject of vigorous scientific debate.
The linked article in the OP says this impact could have happened from 3 million to 12,000 years ago.
One place I can guarantee you he is wrong is he says the megafloods in Washington were just one flood even though deposits in Washington's Wenatchee Valley show literally 40 Rhythmites that were deposited high about the current Columbia River. So absoluty not 1 giant event but at least 40 mega floods:
BlancheSplanchnik
(20,219 posts)Well, good to know! Thanks!
He does tell a good story though, I gotta say.
Codeine
(25,586 posts)Absolute balderdash.
BlancheSplanchnik
(20,219 posts)He tells a good story, though.
Quixote1818
(28,918 posts)Marthe48
(16,897 posts)theorized that meteorites struck the NA ice sheet causing a melt. I think around 12,000. Might have been a big one that broke up.
Up until the early 1960s(I think) most scientists didn't think any meteors had struck Earth, except the recent one in AZ. Then thanks to investigation by Shoemaker (or Levy), scientists started finding craters all over the planet. There's a searchable website. I don't know if I got everything right. Its been years since I read about meteor strikes.
lagomorph777
(30,613 posts)And Antonio Camargo and Glen Penfield found the actual crater in the 1990s, off the Yucatan Peninsula.
https://en.wikipedia.org/wiki/Chicxulub_crater
Marthe48
(16,897 posts)I was thinking of what I read on far north strikes. But can't forget that one.