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    Default Huge asteroid crater found under the ice in Greenland

    The 19-mile-wide impact had remained hidden under a half-mile-thick sheet of ice until it was exposed by a state-of-the-art radar.

    An enormous crater believed to have been caused by an asteroid that slammed into Earth 12,000 years ago has been found beneath the ice in Greenland.

    The 19-mile-wide impact had remained hidden under a half-mile-thick sheet of ice until it was exposed by a state-of-the-art radar system at the University of Kansas.


    Located under the Hiawatha Glacier in remote northwest Greenland, the crater is thought to be the result of an iron asteroid about one kilometre in size that struck the island at the end of the Pleistocene.



    https://news.sky.com/story/huge-aste...nland-11552347

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    Default Re: Huge asteroid crater found under the ice in Greenland

    An enormous, important discovery. This is what Graham Hancock has been talking about for several years: an unthinkable cataclysm causing knock-effects that devastated the entire planet at that time.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    So it wasn’t JUST a comet particularate impact. Imagine the effect on a coastal oriented civilization of any kind of a Tauride stream impact on the Laurentide Ice Sheet of the kind popularized by Randall Carlson and Hancock added to a kilometer wide iron bolide impacting Greenland at the same time.

    There is a Global Flood Myth for a reason.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    Quote Posted by section9 (here)
    So it wasn’t JUST a comet particularate impact. Imagine the effect on a coastal oriented civilization of any kind of a Tauride stream impact on the Laurentide Ice Sheet of the kind popularized by Randall Carlson and Hancock added to a kilometer wide iron bolide impacting Greenland at the same time.

    There is a Global Flood Myth for a reason.
    Yes. We had all the edges and corners to this most important puzzle picture. Now, we have the huge single missing piece that landed right in the middle of the table to complete it.


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    Default Re: Huge asteroid crater found under the ice in Greenland

    Some of the videos I have watched on U tube state that it is possible there was a wave over a mile high.
    Sea shell have been found in very high places.
    It certainly seems that at some point the human race was just about extinct.
    All over the world there is evidence of work in progress quarrying-- moving massive stones that just seemed to come to an abrupt end.
    onawah has been posting quite a few videos that are relevant on this thread started by Skywizard


    https://projectavalon.net/forum4/show...=1#post1237835
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    Default Re: Huge asteroid crater found under the ice in Greenland

    Radar will not give the age of the crater but ice core samples will . Exciting news for sure but I'll wait on the dating until we can get boots on the ground and more confirmation Also with samples they discover might correlate with other mineral samples they have found world wide. There's another twist to the puzzle of the crater: in Kjær's own institution sits a large iron meteorite that was found about 185 miles (300 km) away from the crater site. Could it be that the meteorite and crater originated from the same incoming asteroid breaking up in Earth's atmosphere as it fell to the surface? "I think it's fair to start speculating if those two are linked," Kjær said. "Maybe we found the home of this meteorite. That would be fun."

    But Kring isn't as convinced as the research team that the feature actually has an extraterrestrial origin. "There are thousands, tens of thousands, maybe hundreds of thousands of circular structures on the Earth's surface," Kring said. "Almost none of them are impact craters." He said he would also like to see stronger evidence from rock analysis that the feature was truly caused by an impact, rather than by some other process. [Photos: Hunting Meteorites from Florida Fireball in Osceola]

    He said he's particularly struck by the apparent lack of any measurable climate upheaval that such a large impact would have caused. The team wants to narrow down the date more precisely with future research but is confident that the crater formed between 3 million and 12,000 years ago, likely on the later end of that range. "It certainly should have created global effects, and we just have no hint or signature of that at this time," Kring said.

    (Kjær said that, depending on when precisely the feature formed, it may match the sharp cooling of the Younger Dryas period, which ended about 11,500 years ago, but that it's certainly too early to say.)

    Nevertheless, Kring said he's glad the team is pushing forward on ways to identify unknown features on Earth's surface and understand how the planet has changed over time. And if the site does indeed turn out to be an impact, studying it in more detail could offer helpful insight for planetary protection, which considers the potentially devastating effects that future impacts from the ongoing hail of planetary material could cause.

    "[Asteroids] are a hazard. They are, in fact, a threat to human civilization," Kring said. "We want to better understand the consequences if or when one of those objects actually hits the Earth, and one way to do that is to go into the geological record and measure those impacts."

    For Kjær, what's most exciting isn't even the dramatic collision or its potential successors — it's the act of stumbling upon something unknown. "Look here — the age of discovery is not over yet," he said. "We can still go out here and find things that we didn't see before."

    The research is described in a paper published today (Nov. 14) in the journal Science Advances.




    https://www.space.com/42431-giant-im...nland-ice.html

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    Default Re: Huge asteroid crater found under the ice in Greenland

    It's in all the mainstream media. This article is the best [simple] summary I've yet found, featuring all the implications. (But there may well be many others just as well-presented.) They're calling it the Hiawatha Crater.
    Greenland impact crater could help explain disappearance of woolly mammoths, early humans

    A scarily large meteorite crater has just been discovered in Greenland. It hit the world with the force of 700,000,000 nuclear bombs.

    A massive iron meteorite smashed into Greenland as recently as 12,000 years ago, leaving a crater bigger than Paris that was recently discovered beneath the ice with sophisticated radar.

    The crater is the first of its kind ever found on Greenland — or under any of the Earth’s ice sheets — and is among the 25 largest known on Earth, said the report in the journal Science Advances.

    It is estimated the asteroid would likely have been made largely of iron, measuring about 1.5km across and weighing about 12 tons. The impact which created the 31 kilometres wide crater under the Hiawatha Glacier would have had significant ripple effects in the region, possible even globally, researchers said.

    But its story is just beginning to be told.


    The Hiawatha impact crater covered by the Greenland Ice Sheet and a tongue of ice that breaches the crater’s rim.

    If confirmed, it could have major implications for the tale of humanity itself.

    If confirmed, its dating could establish the Younger Dryas impact hypothesis as fact. It’s a somewhat controversial idea that a large impact in North America some 11,000 to 13,000 years ago during the last Ice Age caused massive wildfires across much of the Americas and Europe, as well as unsettling the weather conveyor belt of the North Atlantic current.

    This in turn lead to the extinction of many megafauna mammals, such as the mammoth and mastodons — and possibly the early humans then occupying the Americas.


    The hidden crater stretches nearly 20 miles (31km) wide. A prominent rim surrounds the depression.

    DEEP IMPACT

    It would have been a spectacle seen across much of the Northern Hemisphere — a huge fireball many times brighter than the Sun, streaking across the sky.

    Then it struck Greenland.

    The resulting impact would have flashed across North America — sending molten projectiles spearing into forests over thousands of square kilometres and setting off enormous fires. And then the tsunamis and clouds of vaporised ice and bedrock circled the globe.


    The location of the Hiawatha crater, hidden under Greenland's icecap.


    The impact would have been huge. But nowhere near as devastating as the dinosaur-killer strike that created the Chicxulub impact crater — some 200km wide — in Mexico some 66 million years ago.

    “There would have been debris projected into the atmosphere that would affect the climate and the potential for melting a lot of ice, so there could have been a sudden freshwater influx into the Nares Strait between Canada and Greenland that would have affected the ocean flow in that whole region,” said co-author John Paden, courtesy associate professor of electrical engineering and computer science at Kansas University.


    The geomorphological and glaciological setting of Hiawatha Glacier, northwest Greenland.

    “The evidence indicates that the impact probably happened after the Greenland Ice Sheet formed, but the research team is still working on the precise dating.”

    That would suggest that the impact happened sometime before the end of the Pleistocene era some 11,700 years ago.

    “It’s likely quite young, geologically speaking,” says study co-author Joseph MacGregor, a glaciologist with the NASA Goddard Space Flight Center. “It’s likely less than three million years old and possibly as young as 12,000 to 15,000 years old.”



    But does the Greenland crater clinch the Younger Dryas impact hypothesis?

    “It’s a very speculative idea, but if this does turn out to be (the missing link), it would have had an outsize impact on human history,” McGregor says.

    “We do not discuss it in the paper, but I think it is a possibility,” adds lead author Kurt Kjær, a glacial geologist and curator at the Natural History Museum of Denmark and the University of Copenhagen. “This may generate a lot of discussion, and we need to find out. We won’t know until we have a proper date.”


    UNEARTHING A CRATER

    The discovery was initially made in the 2015 but an international team of researchers has been working to verify the findings ever since.

    The initial finding was made with data from NASA’s Program for Arctic Regional Climate Assessment and Operation IceBridge.

    More data was collected since then, using more advanced radar technology.

    “So far, it has not been possible to date the crater directly, but its condition strongly suggests that it formed after ice began to cover Greenland", Professor Kjaer says.

    Researchers plan to try and recover material that melted from the bottom of the glacier to learn more about its timing and effects on life on Earth at the time.

    Such a dating would vindicate Younger Dryas impact theorists.



    “I’d unequivocally predict that this crater is the same age as the Younger Dryas,” says James Kennett, a marine geologist at the University of California, Santa Barbara and one of the idea’s original supporters, told Science.

    The climate chaos, the theory argues, would explain why the Clovis peoples’ settlements were abandoned and the megafauna vanished soon afterwards.

    Not all agree.

    “This is a hot potato,” impact crater expert at Purdue University in West Lafayette, Indiana, Jay Melosh told Science. “You’re aware you’re going to set off a firestorm?”

    Lloyd Keigwin, a paleoclimatologist at the Woods Hole Oceanographic Institution in Massachusetts says there is only one solution.

    “Somebody’s got to go drill in there … That’s all there is to it.”
    Last edited by Bill Ryan; 16th November 2018 at 01:09.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    It must have been one of several hits. It dosn't, on it's own, account for the findings of Randal Carlson over on the western side of the US/Canada area.
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    Default Re: Huge asteroid crater found under the ice in Greenland

    Quote Posted by norman (here)
    It must have been one of several hits. It dosn't, on it's own, account for the findings of Randal Carlson over on the western side of the US/Canada area.
    Carlson theorized that a cometary fragment hit near Michigan and liquified much of the Laurentide Ice Sheet as part of a bombardment of the Northern Hemisphere that occurred in a single day, iirc. This bolide could have been part of that bombardment, which explains the sudden rise in worldwide sea levels.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    I"m confused, I thought an asteroid impact would cause global cooling due to atmospheric debris blocking out the sun.
    Quote The Pleistocene Epoch is typically defined as the time period that began about 2.6 million years ago and lasted until about 11,700 years ago.
    If this asteroid landed on or hit the earth aprox 12,000 years ago then it somehow ended the last ice age? How is that?
    How would a major impact such as this cause the last ice age to end?
    -------------------------------------------------------------------------------------------

    Also, as a sidenote, I would like to mention that Billy Meier has a major hit on this one.
    Meier stated that in the war of Atlantis one side sent out a ship and dragged an asteroid to be hurled at the other side, essentially saying that Atlantis and it's war ended with no winners and only losers as all of civilization as basically wiped out due to this asteroid strike.



    Quote In contact 60 dated 8 July, 1976, Semjase gives Billy a detailed explanation of the history leading up to and including the war that led to the total destruction of both Mu in the area of the Gobi desert and Greater Atlantis in the Atlantic Ocean whereby only a few small islands are left, namely the Azore Islands. Briefly, an extremely evil JHWH named Arus and his followers led constant attacks against both cities in order to try and take possession of them. Worldwide wars raged for 2 milleniums. As a result of intrigues, hate and the will for destruction arose amongst the inhabitants of both cities towards each other. The Atlantians commanded a huge fighting fleet of fighter beamships of all types. In a quick attack they completely levelled Mu. However, the scientists of Mu had also developed a most powerful weapon whereby they were able to direct large asteroids to act as huge unstoppable bombs. As the Atlantians rejoiced over their quick decisive victory over Mu, some Mu scientists, who had been notified of the attack while working in space developing their destructive technology, chose an appropriate asteroid and guided her in a suicide mission to completely destroy Atlantis with a force so great, the Earth had, and never will see the likes of it again...As the asteroid entered into the atmosphere, it split into thousands of smaller pieces with a total power greater than 32,000 hydrogen bombs. These crashed down with such force into the ocean that they caused the Earth's crust to break. A giant flood wave the height of 2,300 meters arose and this is what caused the complete submergence of countries and the city of Greater Atlantis. These events transpired approximately 11,500 years ago.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    Quote Posted by DNA (here)
    I"m confused, I thought an asteroid impact would cause global cooling due to atmospheric debris blocking out the sun.
    Quote The Pleistocene Epoch is typically defined as the time period that began about 2.6 million years ago and lasted until about 11,700 years ago.
    If this asteroid landed on or hit the earth aprox 12,000 years ago then it somehow ended the last ice age? How is that?
    How would a major impact such as this cause the last ice age to end?
    Marcus, just as background for other folks reading this:

    The Younger Dryas is the name given to the distinct 1,200 year long cold period itself, which lasted from 12,900 to 11,700 years ago. The hypothesis presented by Graham Hancock and Randall Carlson (and others!) is that the Younger Dryas was initiated by a catastrophic comet or asteroid impact event.

    From https://en.wikipedia.org/wiki/Younge...ct_hypothesis: (extracted/abbreviated)
    The Younger Dryas impact hypothesis ... originally proposed that a large air burst or earth impact of one or more comets initiated the Younger Dryas cold period about 12,900 BP (Before Present).
    ...
    The current impact hypothesis states that the air burst(s) or impact(s) of a swarm of ... comet fragments set areas of the North American continent on fire, causing the extinction of most of the megafauna in North America and the demise of the North American Clovis culture after the last glacial period. The Younger Dryas ice age lasted for about 1,200 years before the climate warmed again. This swarm is hypothesized to have exploded above or possibly on the Laurentide Ice Sheet in the region of the Great Lakes, though no impact crater has yet been identified.
    A couple of notes!
    • The emphasis ^^ is mine. Now, we have an impact crater. (Maybe there'll be others. Teams will certainly start searching for more.)
    • The 12,000 BP date for the Hiawatha event (as stated by some of the researchers) is a very rough estimate of its most recent possible date. If it proves after more research to be 12,900, then that really is the smoking gun that can't possibly be ignored or dismissed by anyone.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    Here's the important 2006 book that was the first to present the Younger-Dryas impact hypothesis:

    Last edited by Bill Ryan; 16th November 2018 at 05:58.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    I'm wondering: Was it big enough to cause a pole shift? Personally I think a pole shift was the reason of the last event that caused great extinction (before humans in our time). I think this asteroid would not be big enough to cause that, though would have a large effect in the Northern Hemisphere.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    Quote Posted by Slobbe (here)
    I'm wondering: Was it big enough to cause a pole shift? Personally I think a pole shift was the reason of the last event that caused great extinction (before humans in our time). I think this asteroid would not be big enough to cause that, though would have a large effect in the Northern Hemisphere.
    Well, if a 1 mile wide asteroid hits an 8,000 mile wide planet at 40,000 mph, there'll be a cataclysmic explosion: all that kinetic energy has to go somewhere.

    But the 8,000 mile wide planet, 5 trillion times as heavy, would remain unmoved. It'd be like hitting a bowling ball with a grain of sand.

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    Default Re: Huge asteroid crater found under the ice in Greenland

    As I wrote, earlier in this thread:
    When one's got the smell of gun-powder smoke, the smoking gun AND the bullets...
    Quote Posted by Hervé (here)
    When one's got the smell of gun-powder smoke, the smoking gun AND the bullets...

    The mystery of mammoth tusks with iron fillings
    By Ned Rozell March 5, 2008

    A giant meteor may have exploded over Alaska thousands of years ago, shooting out metal fragments like buckshot, some of which embedded in the tusks of woolly mammoths and the horns of bison.

    Simultaneously, a large chunk of the meteor hit Alaska south of Allakaket, sending up a dust cloud that blacked out the sun over the entire state and surrounding areas, killing most of the life in the area.


    Embedded iron particles surrounded by carbonized rings in the outer layer of a mammoth tusk from Alaska. Inset photo shows how an object ripped through the tusk. Image courtesy Richard Firestone.

    Such is the scenario envisioned by Rick Firestone, a staff scientist at the Lawrence Berkeley National Laboratory in California. Firestone and his colleagues have found mammoth tusks and a bison skull with nickel-rich iron particles in them on one side, suggesting the metal fragments all came from the same direction.

    Firestone's theory emerged when his colleague, Alan West of Dewey, Arizona, saw at a Phoenix gem and mineral show a mammoth tusk peppered with tiny bits of metal. Intrigued, West and Firestone looked at tusks owned by the same dealer in Calgary. By passing a magnet over mammoth tusks in Calgary, Firestone and West found seven mammoth tusks collected somewhere near the Yukon River and a bison skull from Siberia that had tiny iron fragments burned into them. The fragments also contained nickel.

    "One in 1,000 tusks had this material in it," Firestone said.

    Full article:
    http://alaskareport.com/news28/ned71...moth_tusks.htm

    See this post for further discussion: https://projectavalon.net/forum4/show...l=1#post500017

    Related:
    Carolina Bays: Solved

    =======================================

    The only [apparent?] discrepancy is a dating mismatch since the shot-gunned mammoths time of death is estimated at around 35.000 years ago... or, if the dating is proven accurate, then, said mammoths experienced two distinct extinction level events.
    For an idea of size given by the presence of nano-diamonds, iron and carbon spherules in and/or above the YDB "Black Mat":



    The Younger Dryas Boundary strewnfield is shown (red) with YDB sites as red dots and those by eight independent groups as blue dots. Also shown is the largest known impact strewnfield, the Australasian (purple).

    Last edited by Hervé; 16th November 2018 at 14:46.
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    Default Re: Huge asteroid crater found under the ice in Greenland

    This video helped me to understand how Size really matters, when it comes to Asteroids.


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    Default Re: Huge asteroid crater found under the ice in Greenland

    Quote Posted by Bill Ryan (here)
    Quote Posted by Slobbe (here)
    I'm wondering: Was it big enough to cause a pole shift? Personally I think a pole shift was the reason of the last event that caused great extinction (before humans in our time). I think this asteroid would not be big enough to cause that, though would have a large effect in the Northern Hemisphere.
    Well, if a 1 mile wide asteroid hits an 8,000 mile wide planet at 40,000 mph, there'll be a cataclysmic explosion: all that kinetic energy has to go somewhere.

    But the 8,000 mile wide planet, 5 trillion times as heavy, would remain unmoved. It'd be like hitting a bowling ball with a grain of sand.
    As Bill has pointed out its not just the size of this its the impact speed.
    It is also possible/probable that there were several asteroids hit a roughly the same time.
    There is so much evidence of past cataclysmic events---these recorded also in female DNA bottle necks as seen here is the video regarding Yellow Stone Super Volcano
    Forty minutes into this video there is a section about dramatic reduction of the population.
    Chris


    https://projectavalon.net/forum4/show...=1#post1256064
    Be kind to all life, including your own, no matter what!!

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    Default Re: Huge asteroid crater found under the ice in Greenland

    A very comprehensive and easy-to-read article, with a ton of interesting context. Published today.
    A large asteroid struck Greenland in the time of humans. How did it affect the planet?

    On a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks from beneath it. Kjær had 18 hours to find the mineral crystals that would confirm his suspicions.

    What he brought home clinched the case for a grand discovery. Hidden beneath Hiawatha is a 31-kilometer-wide impact crater, big enough to swallow Washington, D.C., Kjær and 21 co-authors report this week in a paper in Science Advances. The crater was left when an iron asteroid 1.5 kilometers across slammed into Earth, possibly within the past 100,000 years.

    Though not as cataclysmic as the dinosaur-killing Chicxulub impact, which carved out a 200-kilometer-wide crater in Mexico about 66 million years ago, the Hiawatha impactor, too, may have left an imprint on the planet's history. The timing is still up for debate, but some researchers on the discovery team believe the asteroid struck at a crucial moment: roughly 13,000 years ago, just as the world was thawing from the last ice age. That would mean it crashed into Earth when mammoths and other megafauna were in decline and people were spreading across North America.

    The impact would have been a spectacle for anyone within 500 kilometers. A white fireball four times larger and three times brighter than the sun would have streaked across the sky. If the object struck an ice sheet, it would have tunneled through to the bedrock, vaporizing water and stone alike in a flash. The resulting explosion packed the energy of 700 1-megaton nuclear bombs, and even an observer hundreds of kilometers away would have experienced a buffeting shock wave, a monstrous thunderclap, and hurricane-force winds. Later, rock debris might have rained down on North America and Europe, and the released steam, a greenhouse gas, could have locally warmed Greenland, melting even more ice.

    The news of the impact discovery has reawakened an old debate among scientists who study ancient climate. A massive impact on the ice sheet would have sent meltwater pouring into the Atlantic Ocean—potentially disrupting the conveyor belt of ocean currents and causing temperatures to plunge, especially in the Northern Hemisphere. “What would it mean for species or life at the time? It's a huge open question,” says Jennifer Marlon, a paleoclimatologist at Yale University.

    A decade ago, a small group of scientists proposed a similar scenario. They were trying to explain a cooling event, more than 1000 years long, called the Younger Dryas, which began 12,800 years ago, as the last ice age was ending. Their controversial solution was to invoke an extraterrestrial agent: the impact of one or more comets. The researchers proposed that besides changing the plumbing of the North Atlantic, the impact also ignited wildfires across two continents that led to the extinction of large mammals and the disappearance of the mammoth-hunting Clovis people of North America. The research group marshaled suggestive but inconclusive evidence, and few other scientists were convinced. But the idea caught the public's imagination despite an obvious limitation: No one could find an impact crater.

    Proponents of a Younger Dryas impact now feel vindicated. “I'd unequivocally predict that this crater is the same age as the Younger Dryas,” says James Kennett, a marine geologist at the University of California, Santa Barbara, one of the idea's original boosters.

    But Jay Melosh, an impact crater expert at Purdue University in West Lafayette, Indiana, doubts the strike was so recent. Statistically, impacts the size of Hiawatha occur only every few million years, he says, and so the chance of one just 13,000 years ago is small. No matter who is right, the discovery will give ammunition to Younger Dryas impact theorists—and will turn the Hiawatha impactor into another type of projectile. “This is a hot potato,” Melosh tells Science. “You're aware you're going to set off a firestorm?”

    IT STARTED WITH a hole. In 2015, Kjær and a colleague were studying a new map of the hidden contours under Greenland's ice. Based on variations in the ice's depth and surface flow patterns, the map offered a coarse suggestion of the bedrock topography—including the hint of a hole under Hiawatha.

    Kjær recalled a massive iron meteorite in his museum's courtyard, near where he parks his bicycle. Called Agpalilik, Inuit for “the Man,” the 20-ton rock is a fragment of an even larger meteorite, the Cape York, found in pieces on northwest Greenland by Western explorers but long used by Inuit people as a source of iron for harpoon tips and tools. Kjær wondered whether the meteorite might be a remnant of an impactor that dug the circular feature under Hiawatha. But he still wasn't confident that it was an impact crater. He needed to see it more clearly with radar, which can penetrate ice and reflect off bedrock.

    Kjær's team began to work with Joseph MacGregor, a glaciologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who dug up archival radar data. MacGregor found that NASA aircraft often flew over the site on their way to survey Arctic sea ice, and the instruments were sometimes turned on, in test mode, on the way out. “That was pretty glorious,” MacGregor says.

    The radar pictures more clearly showed what looked like the rim of a crater, but they were still too fuzzy in the middle. Many features on Earth's surface, such as volcanic calderas, can masquerade as circles. But only impact craters contain central peaks and peak rings, which form at the center of a newborn crater when—like the splash of a stone in a pond—molten rock rebounds just after a strike. To look for those features, the researchers needed a dedicated radar mission.

    Coincidentally, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had just purchased a next-generation ice-penetrating radar to mount across the wings and body of their Basler aircraft, a twin-propeller retrofitted DC-3 that's a workhorse of Arctic science. But they also needed financing and a base close to Hiawatha.

    Kjær took care of the money. Traditional funding agencies would be too slow, or prone to leaking their idea, he thought. So he petitioned Copenhagen's Carlsberg Foundation, which uses profits from its global beer sales to finance science. MacGregor, for his part, enlisted NASA colleagues to persuade the U.S. military to let them work out of Thule Air Base, a Cold War outpost on northern Greenland, where German members of the team had been trying to get permission to work for 20 years. “I had retired, very serious German scientists sending me happy-face emojis,” MacGregor says.

    Three flights, in May 2016, added 1600 kilometers of fresh data from dozens of transits across the ice—and evidence that Kjær, MacGregor, and their team were onto something. The radar revealed five prominent bumps in the crater's center, indicating a central peak rising some 50 meters high. And in a sign of a recent impact, the crater bottom is exceptionally jagged. If the asteroid had struck earlier than 100,000 years ago, when the area was ice free, erosion from melting ice farther inland would have scoured the crater smooth, MacGregor says. The radar signals also showed that the deep layers of ice were jumbled up—another sign of a recent impact. The oddly disturbed patterns, MacGregor says, suggest “the ice sheet hasn't equilibrated with the presence of this impact crater.”

    But the team wanted direct evidence to overcome the skepticism they knew would greet a claim for a massive young crater, one that seemed to defy the odds of how often large impacts happen. And that's why Kjær found himself, on that bright July day in 2016, frenetically sampling rocks all along the crescent of terrain encircling Hiawatha's face. His most crucial stop was in the middle of the semicircle, near the river, where he collected sediments that appeared to have come from the glacier's interior. It was hectic, he says—“one of those days when you just check your samples, fall on the bed, and don't rise for some time.”


    The hidden crater
    Under a lobe of ice on northwest Greenland, airborne radar and ground sampling have uncovered a giant and remarkably fresh impact crater. Though not as large as the dinosaur-killing Chicxulub impact, Hiawatha crater may have formed as recently as the end of the last ice age, as humans were spreading across North America. Meltwater from the impact could have triggered a thousand-year chill in the Northern Hemisphere by disrupting currents in the Atlantic Ocean.

    In that outwash, Kjær's team closed its case. Sifting through the sand, Adam Garde, a geologist at the Geological Survey of Denmark and Greenland in Copenhagen, found glass grains forged at temperatures higher than a volcanic eruption can generate. More important, he discovered shocked crystals of quartz. The crystals contained a distinctive banded pattern that can be formed only in the intense pressures of extraterrestrial impacts or nuclear weapons. The quartz makes the case, Melosh says. “It looks pretty good. All the evidence is pretty compelling.”

    Now, the team needs to figure out exactly when the collision occurred and how it affected the planet.

    THE YOUNGER DRYAS, named after a small white and yellow arctic flower that flourished during the cold snap, has long fascinated scientists. Until human-driven global warming set in, that period reigned as one of the sharpest recent swings in temperature on Earth. As the last ice age waned, about 12,800 years ago, temperatures in parts of the Northern Hemisphere plunged by as much as 8°C, all the way back to ice age readings. They stayed that way for more than 1000 years, turning advancing forest back into tundra.

    The trigger could have been a disruption in the conveyor belt of ocean currents, including the Gulf Stream that carries heat northward from the tropics. In a 1989 paper in Nature, Kennett, along with Wallace Broecker, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory, and others, laid out how meltwater from retreating ice sheets could have shut down the conveyor. As warm water from the tropics travels north at the surface, it cools while evaporation makes it saltier. Both factors boost the water's density until it sinks into the abyss, helping to drive the conveyor. Adding a pulse of less-dense freshwater could hit the brakes. Paleoclimate researchers have largely endorsed the idea, although evidence for such a flood has been lacking until recently.

    Then, in 2007, Kennett suggested a new trigger. He teamed up with scientists led by Richard Firestone, a physicist at Lawrence Berkeley National Laboratory in California, who proposed a comet strike at the key moment. Exploding over the ice sheet covering North America, the comet or comets would have tossed light-blocking dust into the sky, cooling the region. Farther south, fiery projectiles would have set forests alight, producing soot that deepened the gloom and the cooling. The impact also could have destabilized ice and unleashed meltwater that would have disrupted the Atlantic circulation.

    The climate chaos, the team suggested, could explain why the Clovis settlements emptied and the megafauna vanished soon afterward. But the evidence was scanty. Firestone and his colleagues flagged thin sediment layers at dozens of archaeological sites in North America. Those sediments seemed to contain geochemical traces of an extraterrestrial impact, such as a peak in iridium, the exotic element that helped cement the case for a Chicxulub impact. The layers also yielded tiny beads of glass and iron—possible meteoritic debris—and heavy loads of soot and charcoal, indicating fires.

    The team met immediate criticism. The decline of mammoths, giant sloths, and other species had started well before the Younger Dryas. In addition, no sign existed of a human die-off in North America, archaeologists said. The nomadic Clovis people wouldn't have stayed long in any site. The distinctive spear points that marked their presence probably vanished not because the people died out, but rather because those weapons were no longer useful once the mammoths waned, says Vance Holliday, an archaeologist at The University of Arizona in Tucson. The impact hypothesis was trying to solve problems that didn't need solving.

    The geochemical evidence also began to erode. Outside scientists could not detect the iridium spike in the group's samples. The beads were real, but they were abundant across many geological times, and soot and charcoal did not seem to spike at the time of the Younger Dryas. “They listed all these things that aren't quite sufficient,” says Stein Jacobsen, a geochemist at Harvard University who studies craters.

    Yet the impact hypothesis never quite died. Its proponents continued to study the putative debris layer at other sites in Europe and the Middle East. They also reported finding microscopic diamonds at different sites that, they say, could have been formed only by an impact. (Outside researchers question the claims of diamonds.)

    Now, with the discovery of Hiawatha crater, “I think we have the smoking gun,” says Wendy Wolbach, a geochemist at DePaul University in Chicago, Illinois, who has done work on fires during the era.

    The impact would have melted 1500 gigatons of ice, the team estimates—about as much ice as Antarctica has lost because of global warming in the past decade. The local greenhouse effect from the released steam and the residual heat in the crater rock would have added more melt. Much of that freshwater could have ended up in the nearby Labrador Sea, a primary site pumping the Atlantic Ocean's overturning circulation. “That potentially could perturb the circulation,” says Sophia Hines, a marine paleoclimatologist at Lamont-Doherty.


    NASA and German aircraft used radar to see the contours of an impact crater beneath the ice of Hiawatha Glacier.

    Leery of the earlier controversy, Kjær won't endorse that scenario. “I'm not putting myself in front of that bandwagon,” he says. But in drafts of the paper, he admits, the team explicitly called out a possible connection between the Hiawatha impact and the Younger Dryas.

    THE EVIDENCE STARTS with the ice. In the radar images, grit from distant volcanic eruptions makes some of the boundaries between seasonal layers stand out as bright reflections. Those bright layers can be matched to the same layers of grit in cataloged, dated ice cores from other parts of Greenland. Using that technique, Kjær's team found that most ice in Hiawatha is perfectly layered through the past 11,700 years. But in the older, disturbed ice below, the bright reflections disappear. Tracing the deep layers, the team matched the jumble with debris-rich surface ice on Hiawatha's edge that was previously dated to 12,800 years ago. “It was pretty self-consistent that the ice flow was heavily disturbed at or prior to the Younger Dryas,” MacGregor says.

    Other lines of evidence also suggest Hiawatha could be the Younger Dryas impact. In 2013, Jacobsen examined an ice core from the center of Greenland, 1000 kilometers away. He was expecting to put the Younger Dryas impact theory to rest by showing that, 12,800 years ago, levels of metals that asteroid impacts tend to spread did not spike. Instead, he found a peak in platinum, similar to ones measured in samples from the crater site. “That suggests a connection to the Younger Dryas right there,” Jacobsen says.

    For Broecker, the coincidences add up. He had first been intrigued by the Firestone paper, but quickly joined the ranks of naysayers. Advocates of the Younger Dryas impact pinned too much on it, he says: the fires, the extinction of the megafauna, the abandonment of the Clovis sites. “They put a bad shine on it.” But the platinum peak Jacobsen found, followed by the discovery of Hiawatha, has made him believe again. “It's got to be the same thing,” he says.

    Yet no one can be sure of the timing. The disturbed layers could reflect nothing more than normal stresses deep in the ice sheet. “We know all too well that older ice can be lost by shearing or melting at the base,” says Jeff Severinghaus, a paleoclimatologist at the Scripps Institution of Oceanography in San Diego, California. Richard Alley, a glaciologist at Pennsylvania State University in University Park, believes the impact is much older than 100,000 years and that a subglacial lake can explain the odd textures near the base of the ice. “The ice flow over growing and shrinking lakes interacting with rough topography might have produced fairly complex structures,” Alley says.


    In 2016, Kurt Kjær looked for evidence of an impact in sand washed out from underneath Hiawatha Glacier. He would find glassy beads and shocked crystals of quartz.

    A recent impact should also have left its mark in the half-dozen deep ice cores drilled at other sites on Greenland, which document the 100,000 years of the current ice sheet's history. Yet none exhibits the thin layer of rubble that a Hiawatha-size strike should have kicked up. “You really ought to see something,” Severinghaus says.

    Brandon Johnson, a planetary scientist at Brown University, isn't so sure. After seeing a draft of the study, Johnson, who models impacts on icy moons such as Europa and Enceladus, used his code to recreate an asteroid impact on a thick ice sheet. An impact digs a crater with a central peak like the one seen at Hiawatha, he found, but the ice suppresses the spread of rocky debris. “Initial results are that it goes a lot less far,” Johnson says.

    EVEN IF THE ASTEROID struck at the right moment, it might not have unleashed all the disasters envisioned by proponents of the Younger Dryas impact. “It's too small and too far away to kill off the Pleistocene mammals in the continental United States,” Melosh says. And how a strike could spark flames in such a cold, barren region is hard to see. “I can't imagine how something like this impact in this location could have caused massive fires in North America,” Marlon says.

    It might not even have triggered the Younger Dryas. Ocean sediment cores show no trace of a surge of freshwater into the Labrador Sea from Greenland, says Lloyd Keigwin, a paleoclimatologist at the Woods Hole Oceanographic Institution in Massachusetts. The best recent evidence, he adds, suggests a flood into the Arctic Ocean through western Canada instead.


    Banded patterns in the mineral quartz are diagnostic of shock waves from an extraterrestrial impact.

    An external trigger may be unnecessary in any case, Alley says. During the last ice age, the North Atlantic saw 25 other cooling spells, probably triggered by disruptions to the Atlantic's overturning circulation. None of those spells, known as Dansgaard-Oeschger (D-O) events, was as severe as the Younger Dryas, but their frequency suggests an internal cycle played a role in the Younger Dryas, too. Even Broecker agrees that the impact was not the ultimate cause of the cooling. If D-O events represent abrupt transitions between two regular states of the ocean, he says, “you could say the ocean was approaching instability and somehow this event knocked it over.”

    Still, Hiawatha's full story will come down to its age. Even an exposed impact crater can be a challenge for dating, which requires capturing the moment when the impact altered existing rocks—not the original age of the impactor or its target. Kjær's team has been trying. They fired lasers at the glassy spherules to release argon for dating, but the samples were too contaminated. The researchers are inspecting a blue crystal of the mineral apatite for lines left by the decay of uranium, but it's a long shot. The team also found traces of carbon in other samples, which might someday yield a date, Kjær says. But the ultimate answer may require drilling through the ice to the crater floor, to rock that melted in the impact, resetting its radioactive clock. With large enough samples, researchers should be able to pin down Hiawatha's age.

    Given the remote location, a drilling expedition to the hole at the top of the world would be costly. But an understanding of recent climate history—and what a giant impact can do to the planet—is at stake. “Somebody's got to go drill in there,” Keigwin says. “That's all there is to it.”

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    Scotland Avalon Member greybeard's Avatar
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    Default Re: Huge asteroid crater found under the ice in Greenland

    Its a question of joining the dots.
    The stories from all the ethnic peoples.
    What Graham Hancock has put out and quite a few others.
    Even a look at Edgar Casey trance work which included viewing Atlantis gives an insight.
    In one video a hammer dug up two thirds of which is still enclosed in solid rock--the metal hammer part and the wooden handle just showing.
    Dated before the massive ice age.
    I have no doubt that there was--were--advanced humans on his planet that got virtually wiped out by cataclysmic events like the subject of this thread.

    Chris
    Be kind to all life, including your own, no matter what!!

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  39. Link to Post #20
    UK Avalon Founder Bill Ryan's Avatar
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    Default Re: Huge asteroid crater found under the ice in Greenland

    A very interesting 10 minute video, published today, with a bunch of animations and photos. (Already!) Professor Kurt Kjaer features.


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