Huge crater discovered in Greenland – here's how the impact may have wiped out the mammoths

November 26, 2018 by Kathryn Harriss, The Conversation
An ice-sheet in Greenland’s Inglefield Land is hiding the Hiawatha crater. Credit: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA

Scientists have discovered a 31km wide impact crater beneath the Hiawatha glacier in Greenland. The discovery, published in Science Advances, was made using airborne radar surveys which unveiled a circular bedrock depression beneath the ice. The presence of quartz and other grains and features on the ground helped the team confirm the finding – these showed signs of having been subjected to large shock pressures.

Analysis of the grains also shows that the was most likely made by an iron meteorite more than 1km wide. It would have occurred during the Pleistocene, between about 12,000 and 3m years ago. This is by no means the only large impact crater on Earth, and research shows just how much such features can teach us about the history of our planet – including the evolution of life. So how could the Greenland impact have changed our planet?

Many of the oldest impacts from space occurred on our planet's most ancient crusts and in the centre of its large, continental tectonic plates. Unfortunately, this crust is continually renewed – older rocks are destroyed by weathering processes and the remains are recycled into new rocks. This process destroys evidence of early impacts from large bodies. Also, many (often initially mistaken for extinct volcanic craters) have formed circular lakes, meaning that many features have been lost due to water erosion.

Despite this lack of evidence, we know that meteorite impacts can produce dramatic changes to the local environment. Larger ones can even have a drastic effect on the global environment – bringing about mass extinctions. The huge Chicxulub crater in Mexico, for example, is believed to have contributed to killing the dinosaurs.

An ice-sheet in Greenland’s Inglefield Land is hiding the Hiawatha crater. Credit: Natural History Museum of Denmark, Cryospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD, USA

But how can one localised impact wipe out entire species? The initial impact and shock wave from an asteroid can wipe clear life within a substantial radius. Everything gets scorched from the heat of the impact – producing a desolate barren landscape. Shock waves passing through the body of the planet can also give rise to destructive earthquakes, tsunamis and volcanoes.

But it is the lasting effects of the impact that has the potential to cause the most serious changes. A large volume of debris ejected from the crater can travel far and spread all over the world. As a result, an increased number of particles in the atmosphere can block out sunlight, changing the climate and preventing photosynthesis – ultimately having a devastating effect on the food chain. Eventually the particles in the atmosphere fall back to Earth and light returns, along with life. The species that survive may be better able to prosper in a new world where many larger creatures, as was the case with the dinosaurs, have become extinct.

Clearly, such impact events have redirected the history of the Earth and paved the way to aid in the evolution of our own species. It is interesting to think about whether the world would be the same as it is today if the Chicxulub impact never happened – or even the impact found in Greenland.

Barringer crater. Credit: D. Roddy (LPI)/NASA
Greenland extinction?

There is evidence that three impacts are possibly related to mass extinction events, including the Cretaceous-Palegene events caused by Chicxulub. We also know that the majority of marine species and terrestrial vertebrates became extinct during the Permian Triassic event some 252m years ago, thought to be caused by the asteroid impact leaving behind the Wilkes Land Crater in Antarctica. Meanwhile, the Popigia impact in Siberia about 35m years ago is linked with the Eocene-Oligocene event, which wiped out many marine species.

All these impacts created craters a whopping 100km across or more (170km for Chicxulub), suggesting that the 31km crater in Greenland may not have been as devastating to the Earth. However, it would have drastically changed the local environment and reset the life race within that area.

If it is really true that the Greenland was created 12,000 years ago or more, it could explain a mysterious feature called the Younger Dryas event. This was a sudden and dramatic change in climate – a glacial period about 12,900 to 11,700 years ago, followed by gradual climatic warming. Previously, scientists believed that this event was caused by a meteor exploding before impact, which would also have caused changes to the local environment.

Kurt Kjær collecting sand samples at the front of Hiawatha Glacier. Credit: Svend Funder

The abrupt climate change is thought to have had a drastic effect on the large mammals of North America. For example, it is believed to have helped cause extinction of the mammoths and mastodons. We know that most woolly populations disappeared between 14,000 and 10,000 years ago. Early human hunter gatherers may have also had to adapt to cope with the change in climate from this event by changing hunting habits or even migrating to more suitable areas.

Clearly impact from space can have devastating consequences for life on Earth. So what if one hit today? The Minor Planet Centre in Massachusetts, US, has been collecting and cataloguing the orbits of asteroids and comets since 1947, and NASA has a similar Near Earth Objects programme. If a body is discovered to be on an intercept course there are prevention plans in place, ranging from deflection and launching spacecraft to move the asteroids to a new orbit to blowing the asteroid up. Unfortunately, all these have their drawbacks and take years to plan – meaning this work may be too little too late.

Indeed, the late physicist Stephen Hawkins stated that an asteroid collision "is the biggest threat to our planet" and one that we cannot have control over. Despite all our monitoring and preparation, a large body may sneak up quickly. And, as previous impacts have taught us, while the damage may not be enough to destroy the world, it could drastically change it – maybe even for the better.

Explore further: Crater that killed the dinosaurs reveals how broken rocks can flow like liquid

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dsylvan
1 / 5 (2) Nov 26, 2018
OK physorg, what are you up to?
Are you using this website to help undermine the credibility of science? Unwittingly---or on purpose?
The comment section is bad enough. Now the articles too?
The greatest danger to understanding is opinion masquerading as knowledge.
jonesdave
3 / 5 (4) Nov 26, 2018
OK physorg, what are you up to?
Are you using this website to help undermine the credibility of science? Unwittingly---or on purpose?
The comment section is bad enough. Now the articles too?
The greatest danger to understanding is opinion masquerading as knowledge.


To be fair, the piece is lifted from elsewhere. It is still rubbish though.
Steelwolf
not rated yet Nov 26, 2018
Actually, there are courses detailing the melt of the Younger Dryas and they specifically can link to individual impact craters, even though they may have been in ice they still left the shock traces. These, and the tektites and higher platinum level 'burnt' layer has been found laying across most of North American, Greenland, Iceland, Northern Europe and into Russia.

It has garnered much more attention to it since the Washington State Palouse Scablands are shown to be from a major cataclysmic flooding event, and not several of them as previously suspected. It shows as one major pulse that later had minor pulses, by comparison, but nothing compared to what carved them initially.

The burnt layer has megafauna remains and Clovis points ends at about 12,500 years ago. They are not seen again in the record and is only thousands of years later that there are remains of modern animals and Folsom style points appear.

This one appears to 'maybe' fit the timeline.
Steelwolf
not rated yet Nov 26, 2018
It is not all Woo, people have been looking at it seriously, and it actually does explain the glazing found on some of the Pre-Mayan stonework in Mezoamerica and the end of the largest animals on the Continent, all of the American Megafauna and the Clovis culture disappeared.

People like Randall Carlson have seriously investigated, and had to seriously adapt their thinking as they learned more.

The Younger Dryas Impact Theory:
https://en.wikipe...pothesis

Explains a great deal about that. Shows that sea levels rose by some 400 ft with the melting of the North American Ice Caps, and that a low lying, sea level civilization, like our own, was destroyed and displaced all around the world. India's Indus peoples had to move way inland, people thrived on the Andes Plains, we know that the Mediterranean Sea largely filled at that time as well.

It was a time of Cataclysm for most of the world at that time with 400 ft water suddenly.

jonesdave
3 / 5 (2) Nov 26, 2018
This YD impact nonsense was dealt with here, as well as elsewhere;

The Younger Dryas impact hypothesis: A requiem
Pinter, N. et al.
http://www2.nau.e.../135.pdf
Steelwolf
not rated yet Nov 26, 2018
No, it is an ongoing Question, Hypothesis, with a number of verified facts behind it.

Some people just have their shorts in a wad in the Historical Societies because it throws all of their work out the window as being "The Beginings of Human Culture" only some 5K years ago.

Even though we have a great many archeological sites that date to well before that which show greater sophistication than later builds, in MesoAmerica, Egypt, Israel and even in Europe, people build on top of existing stonework, and the ancient work, in many cases, is the best, stuff we do not replicate ourselves. The Pre-Inca walls in Peru, the fitting etc, we do not do, cannot do, and do not know how They did it.

And it ended some 12,500 years ago or so, along with the Clovis points etc

We have hunter gatherers alive, and well today (que story of dead guy in Andaman Islands) and are at a high space level tech here.

The same disparity may have existed before, with different areas. 400 ft water.
jonesdave
3 / 5 (2) Nov 26, 2018
No, it is an ongoing Question, Hypothesis, with a number of verified facts behind it.


No, it hasn't. As pointed out in the paper. It was sloppy, and made conclusions that simply shouldn't have been made.
Steelwolf
not rated yet Nov 26, 2018
JD, denier that you are, should you have been around in the "mythic" Noah's time, you would have been one of the "Wicked, Uncaring and Nay-saying casters of doubt" that drowned during said disaster because you refuse to listen and refuse to learn.

No, I am not Christian, but that particular story, of the Great Flood, is a world wide told story, with the same Days of the Dead celebrated world wide, BEFORE the spread of Christianity.

This all aligns timewise with the Taurid Meteor Showers, which have been proven to have some very large components to it's cometary debris stream, and shows that it is what is left of a massive comet that broke apart, and we STILL get chunks that hit from it, in November and again in June, we pass through that asteroid stream.

While 'noah's' flood was a more recent happening, as indicated by the Burkle Crater impact, created massive floods at that time, approx 5500 BC, and we are just a reboot of humanity.
Steelwolf
not rated yet Nov 26, 2018
Disasters Happen, you only have to live though a couple of floods, out-race forest fires and have Mt Rainier and Mt St Helens on one's backyard growing up.

We used to climb St Helens before she blew, Beautiful cone it had. And to have half the mountain turn itself into dust and ash in the space of a few minutes...

One easily believes that larger disasters happen, Go to the Barringer Crater in Arizona, only 50k years ago, estimated. Can change one's mind really fast to know this can happen.

Think Chelyabinsk.
dsylvan
not rated yet Nov 26, 2018
OK physorg, what are you up to?
Are you using this website to help undermine the credibility of science? Unwittingly---or on purpose?
The comment section is bad enough. Now the articles too?
The greatest danger to understanding is opinion masquerading as knowledge.


To be fair, the piece is lifted from elsewhere. It is still rubbish though.

True jonesdave, but that physorg would repost an article that presents cherry-picked info in support of a hypothesis concerns me. Reading this article gave me that creepy feeling I was being told what to believe. Too much of that going around these days. Don't want it from my science news source.
AvangionQ
not rated yet Dec 11, 2018
Why is there such a huge range in dating the impact? `between about 12,000 and 3m years ago`
max0r23
not rated yet Jan 03, 2019
'No, it hasn't. As pointed out in the paper. It was sloppy, and made conclusions that simply shouldn't have been made.'

The paper cited is from 2007, and rightly calls out lack of evidence to support the hypothesis. However, the crater was discovered in 2018. It seems the refutation is out of date in light of the new evidence.

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