A Massive Impact Crater Has Been Detected Beneath Greenland's Ice Sheet (gizmodo.com)

An anonymous reader quotes a report from Gizmodo: An unusually large asteroid crater measuring 19 miles wide has been discovered under a continental ice sheet in Greenland. Roughly the size of Paris, it's now among the 25 biggest asteroid craters on Earth. An iron-rich asteroid measuring nearly a kilometer wide (0.6 miles) struck Greenland's ice-covered surface at some point between 3 million and 12,000 years ago, according to a new study published today in Science Advances. The impact would've flung horrific amounts of water vapor and debris into the atmosphere, while sending torrents of meltwater into the North Atlantic -- events that likely triggered global cooling (a phenomenon sometimes referred to as a nuclear or volcanic winter). Over time, however, the gaping hole was obscured by a 1,000-meter-tall (3,200-foot) layer of ice, where it remained hidden for thousands of years. Remarkably, the crater was discovered quite by chance -- and it's now the first large crater to be discovered beneath a continental ice sheet.

Comments

range

[segwonk]

Isn't 12,000 --3,000,000 years a pretty big window?? Or is that par for the course?

Re:range

[mikael]

If it hit slushy water, it would be hard to tell when the actual collision occurred as there isn't any Carbon to do Carbon-dating. They could take ice cores, but that would only tell when the crater was filled in, but not when it was formed.

Re:range

[ClarkMills]

<quote>
Some pre-glacial channels were seen below the ice sheet at the site of the crater, which suggests the Greenland Ice Sheet was already in place when the asteroid struck. 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. The crater appears to be well-preserved—a surprising observation given that ice is a powerful erosive force. The crater is likely fairly young from a geological perspective.

“It is correct that the crater is not well dated but there’s good evidence that it is geologically young, that is, it formed within the last 2 to 3 million years, and most likely it is as young as the last Ice Age [which ended around 12,000 years ago],” Larsen explained to Gizmodo. “We are currently trying to come up with ideas on how to date the impact. One idea is to drill through the ice and get bedrock samples that can be used for numerical dating.”
<unquote>

Re:range

[93 Escort Wagon]

I'm not sure what carbon dating could have to do with this anyway, since carbon dating generally involves the uptake of carbon by biologic systems.

Not to mention that 14C has a half-life of only ~ 5700 years.

Some ice cores from central Greenland have shown undisturbed annual layering (looking at the stable isotope 18O) going back to 125K years... so I would think either this impact occurred before that, or else the region affected by the impact did not reach to the center of the island.

Re: Date Range

[Anonymous Coward]

It also caused climate change. We should outlaw asteroids, perhaps a bunch of world leaders could fly to Paris and sign an agreement saying that no more asteroids are allowed to hit the earth, or the US should pay for damages if one does.

Re: Date Range

[Anonymous Coward]

"Hey, you know this thing we can do something about? Lets not do anything because it's possible for things we can't do something about to also do it! Lol!"

Re: Date Range

[Narcocide]

Honestly it's not a bad idea if only for the reason that we could gain a consensus on whether or not to just let one hit us.

Re:Dinosaurs had feathers

[AlanObject]

Which to believe

Which to believe? The most obvious thing to believe is that your concept of science is drastically wrong.

What you should believe is that scientists will update their hypotheses and conclusions as new data becomes available. Try that out. Then you won't be so perplexed by the list you posted.

Asteroid estimator

[jd]

https://impact.ese.ic.ac.uk/Im...

So, you get a crater roughly the right size in that sort of rock if it is 2.5 km in diameter. You get 0.85 megatonnes equivalent energy, which is next to nothing. No significant global effect.

Re: Dinosaurs had feathers

[miekal]

you are describing debate, not science. What is to be gained by supporting an erroneous conclusion?

Re: Date Range

[c6gunner]

On the bright side, we now have a solution to global warming. Let's get NASA on this stat!

Re:Date Range

[angel'o'sphere]

Many "scientists" examinating old sites like stone henge or sites like https://en.wikipedia.org/wiki/... believe that "the flood" happened about 12000 years ago, just before the end of the ice age. The reason is that magalitic stone sites like this have astronomic properties that point to a particular point in sky. (All over the planet big monuments point to the same point).

That is the suns rising point during the spring equinox 12000 years ago, researchers believe that this is a "time reference". Many sites also show references for water or flooding, as in pictures or smaller buildings pointing to the sign of aquarius. But why that sign would be generally associated with water, I have no idea :D

Yes, I believe that the flood myths we have have a core of truth. Otherwise not every single tribe on the planet had a flood myth. And it is plausible that we once had a civilization on the level of industrialized England 1890 or so, 12000 years ago. Just look at the difference in sea level during the last ice age and now.

Australia was connected with Asia via a land bridge from Indonesia. Japan was connected north and south with China. The mediteranean sea was mostly dry land. Great Britain was connected with mainland Europe ... If there was a high level civilization somewhere and the sea level rose rapidly (and having an impact with weeks of rain) would even be havoc for our civilization today.

Re:Date Range

[shortscruffydave]

I think if it was only 12,000 years ago, we'd have known about it. Physical evidence, written evidence (it would be in the precursor texts to the old testament or something).

Extract from the diary of Olaf Gunnerson form Greenland....."February 27th. Sitting on the glacier looking up to the sky. There's something unusual there, and it's getting bigger. In fact, I think it's coming towards me. I think it m "

Re:Date Range

[Quirkz]

Interesting. I have a new contender for favorite name of event, the Bølling oscillation. Not quite as good as the Defenestration of Prague, but it's up there.

Re:Date Range

[meglon]

Sorry but you're sounding like one of those deranged nutcases on youtube making up shit to fill up their days. You're throwing a bunch of shit together and trying to make it all mean something.

There's a number of ideas as to why a "global" flood myth shows up IN CULTURES NEAR LARGE BODIES OF WATER, one of which being the collapse of the containment of Lake Agassiz. Others point to the eruption of Thera, or even a particularly bad annual flood of the Mesopotamian flood plane. The common point of all of these is that it affected LOCAL areas with catastrophic floods.

Flood myths are not planet wide, they're typically localized to cultures that are near bodies of water. It stands to reason that if something happens which causes a tsunami, a non-advanced culture still believing their god/goddess/gods are real are going to turn it into a myth. Just ask Pat Robertson how his myth creation of "everything bad happens because of gays" is going. There's way too many complete fucking idiots who believe his bullshit, and then give him more money.