Massive Impact Crater Beneath Greenland Could Explain Ice Age Climate Swing

By Anna Groves | November 14, 2018 1:02 pm
A heatmap shows in green a circular crater depression in a red-and-yellow colored surrounding.

Topography under Hiawatha glacier in Greenland, mapped with airborne radar data (1997 to 2014, NASA; 2016 Alfred Wegener Institute). Black triangles and purple circles are elevated peaks around the rim and center. Dotted red lines and black circles show locations of additional sampling. (Credit: Kjæer et al. / Science Advances)

Most of Earth’s surface has been plotted, mapped and measured. And along the way, scientists have turned up a plethora of craters big and small. But there was always one major crater missing.

12,800 years ago, during the Pleistocene, Earth was warming up from its last Ice Age. Temperatures slowly rose while glaciers retreated, that is, until something major happened that triggered a cold snap big enough to leave its mark on the geologic record. Over the course of just decades – the blink of an eye in geological timescales – the planet cooled somewhere between 3 and 11 degrees Fahrenheit (2 to 6 degrees Celsius). The resulting period is known as the Younger Dryas, a mysterious 1000-year blip in history.

Many scientists have suggested – with evidence – that the Younger Dryas was triggered by a meteorite impact. But others have held out, suggesting that volcanic eruptions or, what seems to be the leading favorite, some sort of massive freshwater flood temporarily disrupted climate cycles based out of the North Atlantic. But the main reason scientists have been slow to accept the impact hypothesis is simple: There’s just no crater.

But research out today in the open-access journal Science Advances suggests that maybe we haven’t looked everywhere.

The work, led by Kurt Kjær, professor at the Natural History Museum of Denmark and University of Copenhagen, describes a previously overlooked, 19-mile-wide crater that’s been hiding in plain sight in northwest Greenland’s Hiawatha Glacier. In fact, it’s only about 150 miles from Thule Air Base – the U.S.’s northernmost Air Force base and the place where NASA’s IceBridge planes took flight. You can see about a third of the crater’s rounded outline on Google Earth.

Could this be the sought-after Younger Dryas crater? That depends on how old it is, but it hasn’t been precisely dated yet. Right now, the researchers can only confidently say it’s between 3 million and 12,000 years old – definitely from the Pleistocene.

Dating a crater like this is certainly possible, but because this crater is so deep below the ice in such a remote location, the team couldn’t exactly stop by to pick up some samples. Kjær says they’re working on raising enough interest to embark on the type of field expedition that would be required to core through the 3,000 feet of ice and into the crater itself.

This latest study describes the evidence used to verify that the strange circular feature is, in fact, a crater caused by an asteroid. But early age estimates show that it’s at least possible that this is the 12,800-year-old crater that so many researchers have hoped to find for decades. We’ll have to wait and see.

Rendition of the ice radar survey over Hiawatha Glacier by the Alfred Wegener Institute’s Polar 6 research aircraft. The radar data reveal both the topography beneath the ice and the layering of the ice itself. (Credit: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA)

Rendition of the ice radar survey over Hiawatha Glacier by the Alfred Wegener Institute’s Polar 6 research aircraft. The radar data reveal both the topography beneath the ice and the layering of the ice itself. (Credit: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA)

How They Found The Crater

The research team wasn’t out scouring the globe for craters. They were in Greenland to map Arctic sea ice with NASA’s IceBridge project when a string of serendipitous events led to the discovery.

Joe MacGregor, a co-author on the study who works for NASA’s IceBridge project, says he was lucky enough to be in the right place at the right time to get involved in the crater project.

To conduct the IceBridge surveys, MacGregor explains, a team flies an airplane over the ice and uses radar instruments to map the thickness. To do this, they must fly at a relatively low altitude. But when they’re on their way to a survey, they fly much higher – 10,000 to 15,000 feet – to save fuel. Normally, their radar equipment doesn’t work this high.

Hiawatha glacier, just north of their base at Thule Air Base, was a spot they flew over repeatedly while on the way out to their surveys.

“It just so happened that the guys who were running the radars were trying to test the performance at high altitude most of the time,” says MacGregor. And, surprisingly, the instruments worked, mapping the glacier in the process.

While looking over the resulting radar-generated map, a few scientists from the team noticed the crater-shaped depression in the Hiawatha glacier.

“There was this big circular feature up in northwest Greenland,” says Kjær. “We started to think, wow, could this be right? Could that be an impact crater?”

“Of course then we were faced with the big challenge of finding out if it was actually an impact crater,” says Kjær.

Research Kurt Kjær kneels on all fours on a ridge of sand in front of the glacier's edge.

Kurt Kjær collecting sand samples at the front of Hiawatha Glacier. This sand was transported by the glacier from the bottom of the impact crater to the ice margin, and it has yielded a wealth of information on the impact. (Credit: Svend Funder)

How to Confirm An Impact Crater

As great as it would be to find a giant hunk of space rock or a baby Clark Kent to confirm a geologic indentation’s extra-terrestrial origins, scientists are usually not so lucky when examining a prehistoric crater. But there are a number of tell-tale signs that a big round hole in the ground was caused by a meteor impact.

For instance, there are a number of minerals, like quartz, that undergo significant changes in their properties when exposed to the type of physical force and pressure brought by a meteorite. These changes make the minerals in a crater look different from those in the surrounding bedrock.

Andrew Glikson, an earth scientist at Australian National University who studies asteroid impacts, was not involved with this study but “found it to document a bona-fide impact structure.”

But others, like David Kring at the Lunar and Planetary Institute remain skeptical. Kring comments that “it is difficult to fully assess the data in support of shock-metamorphism, so I am not yet sure convincing, diagnostic evidence of impact exists.” Kring was foundational in confirming the role of the Chicxulub crater’s impact event in the K-T boundary mass extinction.

A Younger Dryas Link?

The authors, their critics, and their supporters were all very clear about one thing: It is too early to link this crater to the Younger Dryas. But assuming it’s a real impact site and if it’s later dated to be 12,800 years old, the implications will be far reaching.

If this crater could be dated to 12,800 years old, it could certainly be credited as the Younger Dryas instigator, and would end this decades-long debate.

What’s more, because of the crater’s location on Greenland’s ice sheet, it’s possible that the impact could’ve caused exactly the kind of massive influx of freshwater to the North Atlantic that the Younger Dryas-flood proponents stand behind.

Hitting an ice sheet with a meteorite could cause a number of water-related effects. According to Allen West, retired geophysicist, the impact could vaporize ice, releasing water molecules into the air that would eventually rain back down; it could destabilize the ice such that it slides into the water; it could create icebergs. Any of these, or a combination of them, could have led to a flood of freshwater into the North Atlantic.

Full Steam Ahead

There’s still much to learn about the new crater, including its age and any impacts it may have had on climate at the time – Younger Dryas or not.

“There’s a lot of new potential things to go after here after this discovery,” says Kjær.

Regardless of the impact of this specific crater, Kjær says, he’s thrilled that the discovery was still possible.

“I think it is just super exciting that given this day and age, 2018, you can still go out in the world and see something that is so big, that nobody has seen before,” says Kjær. “The world’s surface has been surveyed forth and back with all kinds of things, satellites or whatever, but you can still go out and make such a discovery. I think if I was a young scientist or person wanting to do science, I would say, wow, the age of discovery is still honorable.”

  • Kurt Stocklmeir

    this is my theory – for years I have talked about it – a big rock from space hits the ocean – this makes cold water at bottom of ocean go to surface of ocean and this makes an ice age – water at the bottom of the ocean is about 32 degrees – a rock does not need to be extreme big to kill all people on the earth – if a big rock hit the ocean today there would be a big ice age tomorrow and all people on the earth would be dead in about 1 month Kurt Stocklmeir

    • Mike Richardson

      The problem with that theory is that a large asteroid impact in the ocean would superheat the water and vaporizer it as all that kinetic energy from the impactor is converted into heat and released in a multiple megaton explosion dwarfing the largest nuclear bomb ever detonated. Clouds of water vapor would blanket the earth and cool things off quite a bit, as clouds of ash and dust would following a land impact. Basically a nuclear winter scenario, as the very large impact at the end of the Cretaceous period demonstrated. That’s how you get the cooling.

    • Kurt Stocklmeir

      the ocean is extreme cold – water a little under the surface of the ocean has a temperature a lot less than water at the surface – if a big rock from space hit the ocean the rock would first go through gas around the earth – the gas would get hot but the heat would fast leave the earth – this happens all the time at night – temperature at night is less than temperature at day – some water would get hot but it is small compared to the amount of cold water of the ocean that would go to the surface of the ocean – if water flew out of the ocean and if gas around the earth absorbed the water the temperature of the earth would increase – water absorbs energy of the sun a lot more than carbon dioxide – Venus is hot because of water in the gas around Venus – at this time there is more carbon dioxide in the gas around the earth because people cut down trees – these days the temperature of the earth is not normal because there is a lot of water in the air not because of carbon dioxide – if there was a nuclear war – the temperature of the earth would increase to an extreme because a lot of dirt would end up in the gas around the earth – the dirt would stop clouds from being made – because there were not any clouds there would be a lot of water in the air – the water would absorb energy from the sun – all the time rocks and dirt from space hit gas around the earth – any kinetic energy from this does not increase the temperature of the earth – the heat goes out to space – there would be a lot of trouble if a big rock from space hit a super volcano Kurt Stocklmeir

      • Mike Richardson

        No. Just no. Scientists have done small scale experiments testing the effects of high speed impacting bodies, have known since the 19th century that CO2 in the atmosphere has an insulating effect that traps heat, and that after the immediate firestorm from a meteor impact or nuclear war subsided, the massive amount of ash and dust would cause global cooling — as large volcanic eruptions have done in the past. Venus, by the way, is nearly bone dry, as its oceans evaporated long ago and it suffocates under a dense CO2 atmosphere with the only clouds and precipitation in the form of sulfuric acid. This information is easily available from NASA and science websites like this, so there’s no reason to post something so easily refuted. Please read a little more about these topics before posting theories that aren’t even remotely plausible.

        • OWilson

          So scientists “have known since the 19th century that CO2 in the atmosphere has an insulating effect that traps heat, and that after the immediate firestorm from a meteor impact or nuclear war subsided…..”

          (No studies on the aftermath of nuclear war were performed by scientists in the 19th Century :)

          Perhaps you should rephrase that statement, especially since you then go on to lecture the poster:

          “Please read a little more about these topics before posting theories that aren’t even remotely plausible”.


          • Mike Richardson

            Please tell me you didn’t teach English to your students. It’s pretty obvious that one clause refers to knowledge obtained in the 19th century, and the other refers to knowledge learned in the 20th. You really are getting pathetic here. LOL. 😉

          • OWilson


            Much less “obvious” than most on the Trump/Politifact list of 50,000 “falsehoods” told by your President.

            Or even my “half the world” figure of speech that set you off on another of your “Good grief” lying accusations! :)

            You’re still the no life pathetic one following me around, correcting my typos.

            I’m retired with lots of time on my hands.

            And you?

            Don’t you have mail to deliver or something? :)

          • Mike Richardson

            Actually, I think your hero is on record with around 5,000 lies, but I understand accuracy and truth are about as important to you as they are to him. Speaking of which, your “figure of speech” was actually ” half the country, ” not “half the world.” You just make this too easy! ; )

            Besides, with all that time on your hands, would it really hurt to proofread and fact check what you post, so you’d look a little less foolish and dishonest?

            And as for who’s following whom — well, you’re the one that showed up here to chime in response to me, and to drive this thread way off topic. Now that’s the definition of trolling, oh Ironic One. LOL!

            In the meantime, don’t you need to be downing a multitude of beers while you’re sundowning? It’s not like you’re getting sharper anyway, as your post above clearly shows. Cheers! 😁

          • OWilson


            Good bye…..Newman!

          • Mike Richardson

            Occasional… right. 😉

          • OWilson

            Tell us more O Great Socialist Seer of all things Past and all things Future!

            But none of your phony Avanati memory challenged witnesses, ya hear?

            Or perhaps your Jeckyl/Hyde passive/agressive posts on these blogs may have already enlightened us on the effects of addictive substance abuse?

            Oh, and how’s my spelling today?


          • Mike Richardson

            Your spelling is better, though you did misspell “Avenatti.” Your cognitive functioning and grasp of irony, particularly in light of your transparent efforts at projection, continue to fail spectacularly. I mean, you’ve shown readers your own problems with memory and facts here, and a quick perusal of your posts will reveal s true Jekyll/Hyde personality — heck, compare the hostile off-topic trolling here to your efforts at appearing to appreciate science on some of the other Discover blog posts. It’s quite humorous.

            But maybe you are better at predicting the future than I am — how did your pronouncements on the mid-terms go? I hope you put your money where your mouth is on those! LOL!

            And it’s hardly speculating on substance abuse when you proclaim your love for a particular beer with the enthusiasm of the newest Supreme Court justice. Presidente Lite, right? 😉

            Of course, what’s missing in any of your trolling responses is an actual substantive comment on the topic of the impact crater and the potential effects of this ancient impact on climate. Are you really disputing what I said in response to Kurt, and supporting his position? By all means, demonstrate your scientific knowledge here.

            Otherwise, actually mean it when you say goodbye. And by way of goodbye, I’ll leave you with your favorite presidential quote –“Kiss it. ” 😉

          • OWilson

            No that was your Slick Willie quote when he dropped his pants in front of low level State Employee Paula Corbin Jones, and ordered her to ,”Kiss it”!

            He was Impeached, fined and disbarred for that little episode, remember? (Not for the consensual Lewinsky deal!)

            I hear that more then “half the country” wanted him and his missus back in the WH. Lol

            Have a nice day,….Newmannn! :)

          • StanChaz

            Your so-called Slick Willie,
            who left the presidency & country with a budget surplus,
            just smiled at his rabid right-wing detractors and said: “Grab them by the midterms”!
            And the people responded, in record numbers.

            But from the nature of your sour-grapes ranting I surmise it wasn’t such a nice day for you deplorables when the Blue Wave waterboarded both you & il Duce Trump:)))

            My advice, dear fellow, is to take two Pelosi’s and call me in the morning.
            Followed by a Stormy Daniels gargle of course. Lol
            Or better yet, just “kiss it” (i.e. my liberal posterior).

            As for the newly discovered Greenland impact crater, since it’s at the edge of an ice sheet perhaps with accelerating global warming we’ll have answers sooner rather than later. Especially with regard to the potentially deleterious effects of massive fresh water intrusion into the North Atlantic and its crucial ocean currents -whether from such an impact or from global warming itself. Of course by then, with President Trump’s inept “assistance”, it might very well be too late.

          • OWilson

            Have a nice day, y’all!


          • Lorie Franceschi

            Mike, it is “whom is following whom” not “who’s following whom”. Please fact check your english

          • Mike Richardson

            Incorrect. The first pronoun is the subject, so “who” is proper. The second pronoun follows the verb and is the object, so “whom” is correct there. You can fact check with Oxford online. By the way, did you have some contribution to make towards the actual topic of the blog article? :)

      • Popcorn Joe

        Hello Kurt… You wrote, > (“Venus is hot because of water in the gas around Venus”)……… Ummm; no!!

        Astronomers have detected that the atmosphere of Venus consists of 0.002% water vapor, or practically none.

        Venus is hot because the atmosphere of Venus is a very thick 96% CO2 or almost all CO2…. Because of that, the surface of Venus is hot enough to melt lead.

        A CO2 level in the 400ppm levels does not cause Erath’s surface temperature to be hot enough to melt lead, but is it hot enough in the ocean’s now to kill all of he ocean life and it has begun to do that by killing the lowest rung of the chain of life on Earth, the coral reefs… The coral reefs are now rapidly dying.

        • Scruffy Scirocco

          Global warming contribution of CO2 increases linearly with concentration from 0 ppm to about 40 ppm. After that it levels off as CO2 increases, because all the energy that can be absorbed in the very narrow absorption band of CO2 has been absorbed, and the atmosphere becomes opaque at those wavelengths. You can’t increase the amount it absorbs without increasing the amount of energy available to absorb.

          For most of the bandwidth, CO2 is 99% transparent to IR radiation and there is no measurable interaction. Unless you get into very high concentrations, like 960,000 ppm, when the entire bandwidth becomes opaque, and all the IR energy is absorbed the by the gas.

          CO2 absorption capability does not track linearly with concentration at levels where photosynthetic and oxygen breathing life can coexist.

    • Objectivist

      I now have my movie plot to submit to some studio: the walking frozen dead

  • Popcorn Joe

    When did that massive asteroid hit under Greenland? And how did it hit under Greenland without hitting Greenland?

  • Kurt Stocklmeir

    Hi Popcorn Joe and Mike – I have a degree in physics and years of graduate classes in physics math and computer science – I get information from science people – you guys get fake news – people can use bing – search – American Chemical Society water vapor temperature earth – science people know water can absorb a lot more energy from the sun than carbon dioxide – fake news carbon dioxide is changing the weather of the earth – a lot of things can change the weather of the earth – people do not know what is changing the weather of the earth – I am not saying carbon dioxide is good – people cut down trees and burn most of them – carbon dioxide goes into the air because they burn the trees – use bing – search – how many trees cut down each year – fake news if there is a nuclear war there will be a nuclear winter – I think all the dirt will keep water in the air and the temperature will increase to an extreme – I guess a lot of people will die because dirt will end up in their lungs – a lot of science people do not think there will be a nuclear winter if there is a nuclear war – fake news is all over tv – people do not know how much water in on Venus – I read a lot of things that science people wrote about water on Venus – fake news comets and rocks from space killed a lot of animals and plants on the earth – a lot of science people think that is junk – fake news comets and rocks from space hit land this made a lot of dirt go in the air and there was an ice age – a lot of science people think that is junk – people can search the internet for these things – people can see that a lot of science people do not think those things are true – people think a lot of things because of fake news Kurt Stocklmeir

    • Mike Richardson

      Fake news! 😂😆😄

    • StanChaz

      Is that you Donald?
      Too many cheeseburgers today?


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