Prehistoric climate change due to cosmic crash in Canada: Team reveals cause of global climate shift 12,900 years ago

Sep 02, 2013
An artist's rendition of mastodons, camels and a ground sloth before the environmental changes of the Younger Dryas led to their extinction. Credit: Barry Roal Carlsen, University of Wisconsin

For the first time, a dramatic global climate shift has been linked to the impact in Quebec of an asteroid or comet, Dartmouth researchers and their colleagues report in a new study. The cataclysmic event wiped out many of the planet's large mammals and may have prompted humans to start gathering and growing some of their food rather than solely hunting big game.

The findings appear next week in the online Early Edition of the Proceedings of the National Academy of Sciences.

The impact occurred about 12,900 years ago, at the beginning of the Younger Dryas period, and marks an abrupt global change to a colder, dryer climate with far-reaching effects on both animals and humans. In North America, the big animals all vanished, including mastodons, camels, giant ground sloths and saber-toothed cats. Their human hunters, known to archaeologists as the Clovis people, set aside their heavy-duty spears and turned to a hunter-gatherer subsistence diet of roots, berries and smaller game.

"The Younger Dryas cooling impacted human history in a profound manner," says Dartmouth Professor Mukul Sharma, a co-author of the study. "Environmental stresses may also have caused Natufians in the Near East to settle down for the first time and pursue agriculture."

The high temperatures of the meteorite impact 12,900 years ago produced mm-sized spherules of melted glass with the mullite and corundum crystal structure shown here. Credit: Mukul Sharma

It is not disputed that these powerful environmental changes occurred, but there has long been controversy over their cause. The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the that move tropical water northward, resulting in the cold, of the Younger Dryas.

But Sharma and his co-authors have discovered conclusive evidence linking an extraterrestrial impact with this environmental transformation. The report focuses on spherules, or droplets of solidified molten rock expelled by the impact of a comet or meteor. The spherules in question were recovered from Younger Dryas boundary layers at sites in Pennsylvania and New Jersey, the layers having been deposited at the beginning of the period. The geochemistry and mineralogy profiles of the spherules are identical to rock found in southern Quebec, where Sharma and his colleagues argue the impact took place.

"We have for the first time narrowed down the region where a Younger Dryas impact did take place," says Sharma, "even though we have not yet found its crater." There is a known impact crater in Quebec—the 4-kilometer wide Corossal crater—but based on the team's mineralogical and geochemical studies, it is not the impact source for the material found in Pennsylvania and New Jersey.

Using a binocular microscope, Dartmouth geochemist Mukul Sharma examines impact-derived spherules that he and his colleagues regard as evidence of a climate-altering meteor or comet impact 12,900 years ago. Credit: Eli Burakian

People have written about many impacts in different parts of the world based on the presence of spherules. "It may well have taken multiple concurrent impacts to bring about the extensive environmental changes of the Younger Dryas," says Sharma. "However, to date no impact craters have been found and our research will help track one of them down."

Explore further: NASA's HS3 mission continues with flights over Hurricane Gonzalo

More information: Origin and provenance of spherules and magnetic grains at the Younger Dryas boundary , www.pnas.org/cgi/doi/10.1073/pnas.1304059110

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Torbjorn_Larsson_OM
3.1 / 5 (9) Sep 02, 2013
Sigh. This again: "We have examined individual magnetic objects from two well-dated YDB sites, which were claimed to be enriched in Ir. Although these objects have high Os concentration, they have terrestrial Os isotope signatures." [ http://gradworks....497.html ]

Even Darthmouth itself acknowledges the grains are not relevant evidence.

And this minority view has become tedious: "These researchers argue that this material, which dates back nearly 13,000 years, was formed at temperatures of 1,700 to 2,200 °C (3,092 to 3,992 °F) as the result of a bolide impact. They argue that these findings support the controversial Younger Dryas Boundary (YDB) hypothesis, that the bolide impact occurred at the onset of the Younger Dryas.[19] The hypothesis has been largely questioned by research that stated that most of the conclusions cannot be repeated by other scientists, misinterpretation of data, and the lack of confirmatory evidence." [Wikipedia]
ryggesogn2
2 / 5 (24) Sep 02, 2013
"The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas."

Now I see why there is so much opposition to an impact theory, the classic theory supports AGW.
runrig
4.4 / 5 (7) Sep 02, 2013
"The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas."

Now I see why there is so much opposition to an impact theory, the classic theory supports AGW.


In what way?
ubavontuba
1.8 / 5 (20) Sep 02, 2013
Hey, maybe that 275 mile wide Hudson Bay impact idea might bear further scutiny after all...?
cantdrive85
1.2 / 5 (20) Sep 02, 2013
Spherules are produced by electric discharge, the fact they haven't found a crater is no problem for this POV.
r2vettes
1.2 / 5 (11) Sep 02, 2013
Quebec would have still been covered by very thick glaciers 13k years ago. The suspect comet or asteroid would have left little if any crater. If an ice dam ruptured and released so much fresh water that the oceanic conveyor belt stopped, then will it happen with the rapid glacial melt experienced now? So predict another ice age coming instead of a superheated planet
PoppaJ
3.1 / 5 (9) Sep 02, 2013
This would go along way to explaining why there is some advanced architecture in south America that suddenly stops and is later replaced by much more primitive building methods. Only to re evolve to advanced in the last 2000 years. It would also explain why even when Europeans came to America the native Americans were hardly more than hunter gathers. An impact centered on the north American continent really makes sense.
Shootist
2.3 / 5 (18) Sep 02, 2013
Hey, maybe that 275 mile wide Hudson Bay impact idea might bear further scutiny after all...?


No.
ubavontuba
1.7 / 5 (19) Sep 02, 2013
Hey, maybe that 275 mile wide Hudson Bay impact idea might bear further scrutiny after all...?
No.
Sure, it's far fetched, as it doesn't have the expected geologic telltales, but if the area was covered with a couple of miles of ice beforehand, can an impact be softened enough to prohibit much of the expected crater topology and geology ...particularly high temperature attributes?

JohnGee
2.4 / 5 (19) Sep 03, 2013
Ubavontuba thinks climate change is a scam, but he thought the LHC would destroy the world. What a gullible moron.

[The LHC] is dangerous. Clearly the arguments put forward by the safety committee are wrong.
(Page 1)

Did you not understand that naturally occurring collisions are completely different (relative to the earth) than the CERN collisions?


Change is a very good thing (mostly). That doesn't mean we should commit to every potentially dangerous activity without due consideration. The safety committee got their arguments wrong. The safety committe needs to reconvene and reconsider.


That's incorrect. The lesson of Icarus wasn't about not trying new things (he did), but rather it was about not being foolish and cocky (while trying the new thing). To conduct this experiment, in spite of the fact that the safety committee got it wrong, would be foolish and cocky.
(Page 4)

http://www.physfo...amp;st=0
JohnGee
2 / 5 (15) Sep 03, 2013
No matter how "miniscule" the risk, the stakes are too high (literally, the world!). This experiment should be moved off world.
(Page 4)

I don't need to dig any further than that, but it goes on and on and on.

So why no concern over the climate Chicken von Little?
ubavontuba
2.3 / 5 (21) Sep 03, 2013
Ubavontuba thinks climate change is a scam
As far as I know, only in regards to the poor quality science.

ubavontuba
2.3 / 5 (19) Sep 03, 2013
So why no concern over the climate?
Who says I'm not concerned?

Generally speaking, the environment concerns me greatly. This is why I feel the quality of the science is so important.
NikFromNYC
2.1 / 5 (22) Sep 03, 2013
Background on JohnGee who keeps sending me creepy blank SMS messages on Phys.org:
http://s8.postimg...iban.png

"ChristianTaliban.org is dedicated to the teaching of moral and ethical values and to protecting Earth and all its creatures." / "Yes the "Christian Taliban" is diligently working toward an America where we will be forced to worship their concept of God or face the consequences of their tactics of terror. We will live in a nation where Jewish, Muslim, and Hindu children will be forced to pray to a vengeful and hard-hearted God who will proclaim that they will burn in the fires of hell because a loveless and cruel concept of Jesus is not their personal savior. Homosexuals, human rights activists, environmentalists, women's rights advocates, and others will be persecuted, jailed, and perhaps eventually executed...."
http://www.Christ...iban.org
JohnGee
2.4 / 5 (17) Sep 03, 2013
Are you trying to associate me with the Christian Taliban? It's pretty obvious I despise Christianity, even from the quote you posted. You aren't very bright for having a PhD.
NikFromNYC
2.5 / 5 (19) Sep 03, 2013
JohnGee, why are you sending me blank messages?
http://s18.postim...eepy.jpg
JohnGee
1.9 / 5 (16) Sep 03, 2013
Because you touch yourself.
ubavontuba
2.1 / 5 (18) Sep 03, 2013
JohnGee, why are you sending me blank messages?
Obviously, he does this to be annoying, for the sake of being a bully. I guess he has nothing better to do. Maybe he's a jailbird or a confined mental patient.

NikFromNYC
1.8 / 5 (20) Sep 03, 2013
Hatred undid the Global Warming scam, JohnGee. As reasonable folk presented inquiries on seemingly innocent climate outreach sites, they were spitroasted in a bonfire of hate instead of reasoned back with, so they headed to what is now the most popular science site on the Net and populated its blogroll, eventually producing a crowd sourced collection of debunking info that now includes professional videos, alas not at the original Kickstarter level since the Evil Oil Money is an urban myth, unless you're Al Gore. Hate wont hurt skeptics, JohnGee, but your heart will hate your right back for it one day:

"When you consider chronically hostile people, their frequent bouts of anger experienced poses a subtler even greater threat. That's because the frequent high-pressure blood surges tend to wear down the smooth lining of the artery walls, creating a roughened foothold for artery-clogging plaque deposits."

*DANGER* *JOHNGEE*
http://topher.com...project/
*DANGER *JOHNGEE*
Gmr
3.1 / 5 (19) Sep 03, 2013
Translation for those who might not understand Nik: when people realized from our goal post moving that we weren't interested in actual discussion or reasoned debate, we took our toys and went home. Creating inbred exclusive enclaves of self congratulatory content and a propaganda filled environment of yes men was our only recourse. Now we keep thinking we have debate skills, but keep running into undertows after our vast experience in our private kiddy pools.
runrig
3.5 / 5 (11) Sep 03, 2013
Hatred undid the Global Warming scam, JohnGee. As reasonable folk presented inquiries on seemingly innocent climate outreach sites, they were spitroasted in a bonfire of hate instead of reasoned back with....

"Reasonable folk" I have no quarrel with and nor does climate science - that's all part of the inherent weeding out of bad science that "science" entails.
It's those in their own private world of the anti-AGW Blogosphere that I/others have a problem with. You don't accept that science has dealt with your "reasonable inquires" and dismissed them for lack of correlation/causation physics. A reasonable person would move on - the unreasonable merely shrink back into that paranoic world and shout louder and more unreasonably. This has repercussions - and you see that from some quarters. Human nature. Just because you shout louder and often with drizzles of verbal diarrhea, stating look, look, I'm right because I and *whoever* says so, + Gore is hypocrite - doesn't make it so.
Shootist
2.1 / 5 (15) Sep 03, 2013
Hey, maybe that 275 mile wide Hudson Bay impact idea might bear further scrutiny after all...?
No.
Sure, it's far fetched, as it doesn't have the expected geologic telltales, but if the area was covered with a couple of miles of ice beforehand, can an impact be softened enough to prohibit much of the expected crater topology and geology ...particularly high temperature attributes?



No, again. Impact craters are easy, apart from radiation they are just like craters produced by nuclear explosion. the signs are unmistakable (ever after 3 billion years and 25 km of crust has been eroded away. http://www.space....nd.html)
ryggesogn2
1 / 5 (14) Sep 03, 2013
"The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas."

Now I see why there is so much opposition to an impact theory, the classic theory supports AGW.


In what way?

If the climate change was caused by an asteroid impact and not a rush of fresh water messing up Gulf Stream current, then one of the worries of AGWites, Greenland melting, won't have the impact predicted.
Neinsense99
2.5 / 5 (13) Sep 03, 2013
"The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas."

Now I see why there is so much opposition to an impact theory, the classic theory supports AGW.


In what way?

If the climate change was caused by an asteroid impact and not a rush of fresh water messing up Gulf Stream current, then one of the worries of AGWites, Greenland melting, won't have the impact predicted.

It does not have to be only one or the other, at least not for people who can handle nuance.
Neinsense99
1 / 5 (9) Sep 04, 2013
"The classic view of the Younger Dryas cooling interlude has been that an ice dam in the North American ice sheet ruptured, releasing a massive quantity of freshwater into the Atlantic Ocean. The sudden influx is thought to have shut down the ocean currents that move tropical water northward, resulting in the cold, dry climate of the Younger Dryas."

Now I see why there is so much opposition to an impact theory, the classic theory supports AGW.


In what way?

If the climate change was caused by an asteroid impact and not a rush of fresh water messing up Gulf Stream current, then one of the worries of AGWites, Greenland melting, won't have the impact predicted.

It does not have to be only one or the other, at least not for people who can handle nuance.

Not only could there be two factors at play, it's also possible that an impact in the right location could have triggered a massive flood of fresh water, especially if it destroyed an ice dam.
katesisco
1.2 / 5 (14) Sep 05, 2013
Consider: the fresh water into the Atlantic has long been debunked; the ice melt went into the McKenzie and to the Pacific. Why the real data has not been distributed is that this sudden stop to civilization lends itself to an extraterrestrial cause.
Lets think: what other causes could there be?
Let's look at our sun. Sol is currently hanging between magnetic reversals with the result being two of the same magnetic polarity. Science admits this happened last reversal. It may be the common occurrence for all we know. This in-between state is responsible for our excessive radiation bath due to the changed shape of the heliosheath.

New findings about our Earth are daily discovered. Lithosphere thought to dive into the molten magma is found to remain unmelted and reemerge. Life under the bottom of the ocean may be hundreds of miles thick and consume unknown gases and produce unidentified elemental by products.
katesisco
1.2 / 5 (13) Sep 05, 2013
Now consider what would happen if the hung reversal with its pent up energy completed.
Would the Earth crust release large amount of earth gases? Carbon dioxide or methane or other toxic material in a huge reservoir releasing suddenly in a blow out? That would put an end to life where ever the blow out occurred and hamper the existence of life all over the globe.

http://www.nuclearplanet.com/

rocksy
not rated yet Sep 08, 2013
Just finished ready Ragnarok: the age of fire and ice by ignatius Donnelly when I saw this article same ideas only the book is form 1882