Great beasts peppered from space

**Parihaka** · 12-13-2007, 00:00 AM

Quote:

By Jonathan Amos
Science reporter, BBC News, San Francisco

Tusk markings (BBC)
Startling evidence has been found which shows mammoth and other great beasts from the last ice age were blasted with material that came from space.

Eight tusks dating to some 35,000 years ago all show signs of having being peppered with meteorite fragments.

The ancient remains come from Alaska, but researchers also have a Siberian bison skull with the same pockmarks.

The scientists released details of the discovery at a meeting of the American Geophysical Union in San Francisco, US.

They painted a picture of a calamitous event over North America that may have severely knocked back the populations of some species.

Blast direction

"We think that there was probably an impact which exploded in the air that sent these particles flying into the animals," said Richard Firestone from the Lawrence Berkeley National Laboratory.

"In the case of the bison, we know that it survived the impact because there's new bone growth around these marks."

Artist's impression of mammoth (BBC)
Large quantities of mammoth tusk material are now in collections
And geoscience consultant Allen West added: "If the particles had gone through the skin, they may not have made it through to vital organs; but this material could certainly have blinded the animals and severely injured them."

The mammoth and bison remains all display small (about 2-3mm in size) perforations.

Raised, burnt surface rings trace the point of entry of high-velocity projectiles; and the punctures are on only one side, consistent with a blast coming from a single direction.

Viewed under an electron microscope, the embedded fragments appear to have exploded inside the tusk and bone, say the researchers. Shards have cut little channels.

The sunken pieces are also magnetic, and tests show them to have a high iron-nickel content, but to be depleted in titanium.

The ratios of different types of atoms in the fragments meant it was most unlikely they had originated on Earth, the team told the AGU meeting.

Magnetic hunt

The discovery follows on from the group's previous research which claimed a more recent space collision - some 13,000 years ago.

The researchers reported the discovery of sediment at more than 20 sites across North America that contained exotic materials: tiny spheres of glass and carbon, ultra-small specks of diamond and amounts of the rare element iridium that were too high to be terrestrial.

The scientists also found a black layer which, they argued, was the charcoal deposited by wildfires that swept the continent after the space object smashed into the Earth's atmosphere.

It was just a tiny magnet on a string, but very strong. It would swing over and stick firmly to these little dots
Allen West
"We had found evidence of particle impacts in chert, or flint, at a Clovis Indian site in Michigan," Dr Firestone said.

"So, we got the idea that if these impacts were in the chert, then they might likely also have occurred in large surfaces such as tusks; and we decided it was worth a shot to go look for them."

Allen West began the hunt at a mammoth tusk sale in his home state of Arizona.

He immediately found one tusk with the tell-tale pockmarks and asked the trading company if he could look through its entire collection. He sorted literally thousands of items.

"There are many things that can cause spots, such as algae, and there were a few of those; but I was only interested in the ones that were magnetic," he recalled. "It was just a tiny magnet on a string, but very strong. It would swing over and stick firmly to these little dots."

The search turned up a further seven ivory specimens of interest, together with the bison skull.

Further clues

But having gone out and tested the hypothesis of tusk impacts, and having apparently uncovered such items - the team was then astonished to find the animal remains were about 20,000 years older than had been anticipated.

The researchers are now considering a number of possibilities - one that could even tie the older remains to the younger event.

Tusk particle (Firestone et al)
The embedded particles have a high iron-nickel content
"People who collect these items today in Siberia and Alaska frequently find the tusks sticking out of the permafrost or eroding out of a riverbank," explained Mr West.

"Maybe, these were tusks from dead animals that were just exposed on the surface, so when this thing blew up in the atmosphere, it would have peppered them. The date could really be anywhere from 13,000 to 35-40,000 years ago."

The team believes there must still be peppered tusks out there that can be dated to 13,000 years ago, and the hope is that the AGU presentation will prompt museums and collectors to look through their archives.

"There should also be a layer of this same meteoritic material in the sedimentary record. It's probably very thin. If we can locate the right place and it hasn't been turbated, we should be able to find this layer; and it shouldn't be too different from the impact layer we found for the 13,000-year event," said Dr Firestone.

Neither proposed impact can yet be tied definitively to any craters - if there ever were any. The team also needs to explain how the bison and mammoth remains can show similar damage when they were widely separated geographically.

Past puzzle

The intriguing question is how space impacts might fit into the extinction story of the ice age beasts. The mammoth, their elephant cousins the mastodon, sabre-toothed tigers, some bears, and many other creatures all disappeared rapidly from the palaeo-record about 10,000 years ago.

Their loss has traditionally been put down to either climate change and/or the efficient hunting technologies adopted by migrating humans.

Could impacts have also weakened these populations?

It might be just one more element to factor into what is a really complex picture, commented Dr Ian Barnes from Royal Holloway University of London, UK.

The British researcher studies the DNA of ancient animals to try to glean details of how their populations changed over time.

He said there were some interesting markers in the genetics of different creatures some 30,000 to 45,000 years ago - but it was extremely hard to draw firm conclusions.

"For us the difficulty is that we see patterns but we don't understand what the underlying process is; so it becomes difficult to ascribe causation," he explained.

"Just as in a modern crime scene, it's very difficult to piece all the evidence together and say precisely what was going on; which event led to any particular outcome."

But he added: "Certainly, you can't imagine it helped the animals having a large meteorite hit the Earth's atmosphere and pellet them with shot."

dalem · 12-13-2007, 01:10 AM

I hate these constant efforts to tie in possible impacts with extinctions.

-dale

Desdemona · 12-13-2007, 09:07 AM

I kind of like the varying hypothesis of extinction. It reinforces my thoughts that global warming is far greater impacted by things we have no control over.

Debbie · 12-13-2007, 12:52 PM

Quote:

Originally Posted by dalem

I hate these constant efforts to tie in possible impacts with extinctions.

-dale

RustyBattleship · 12-13-2007, 12:57 PM

It sometimes seems like old hat every time a science show has another version of asteroid strike.

However, this last one is a shocker. It indicates an irradication of large animals (Mammoths, etc.) and the Clovis people by a northern asteroid strike about 13,000 years ago. Yet other fossil evidence shows a similar strike about 30,000 years ago.

I think we should keep a stockpile of thermo-nukes around with rockets and probes that can land on one of these incoming asteroids to whack it out of collision course or break it up altogether.

Yes, I said land on it. I was watching one show where the "expert" scientists think it should be a proximity blast several miles from the asteroid. Ummm, and what do you think is out there to transfer the shock wave? Space is rather void of a compressible, shock transferring atmosphere.

Oh. One other thing that worries me. The last time we tracked an asteroid that could have caused major damage was AFTER it passed BETWEEN us and the Moon. I think we need to keep our targeting RADAR looking for incomings rather than "Whew. That was close".

Canmoore · 12-13-2007, 17:49 PM

I think humans would survive a meteor strike. Hell, we were bent on surviving nuclear war for 40 years. Whats the difference between that and surviving a meteor strike?

RustyBattleship · 12-13-2007, 18:04 PM

Quote:

Originally Posted by Canmoore

I think humans would survive a meteor strike. Hell, we were bent on surviving nuclear war for 40 years. Whats the difference between that and surviving a meteor strike?

BIG difference. A meteor the size of a city block coming in at 17,000 miles per hour would cause more death and destruction than all of our stockpiled nuclear weapons put together.

So far we have been very fortunate that only some small meteors have hit inhabited areas (one going through the trunk of a parked car). The fair sized one in Siberia was in a totally desolate and uninhabited region.

The one that created Meteor Crater in Arizona is estimated to have killed all above ground life for several miles around. And that crater is "only" a mile in diameter with the estimated size of the meteor being that of Nash Ambassador.

dalem · 12-13-2007, 18:56 PM

Quote:

Originally Posted by Canmoore

I think humans would survive a meteor strike. Hell, we were bent on surviving nuclear war for 40 years. Whats the difference between that and surviving a meteor strike?

Even some of the smaller asteroids and comet fragments, if they impacted, would dwarf the energy output of all our nukes put together.

A "big one" could cause immense damage. Human-ending? Not necessarily. But nothing to sneeze at.

-dale

Canmoore · 12-13-2007, 22:13 PM

Quote:

Originally Posted by dalem

Even some of the smaller asteroids and comet fragments, if they impacted, would dwarf the energy output of all our nukes put together.

A "big one" could cause immense damage. Human-ending? Not necessarily. But nothing to sneeze at.

-dale

Yes a meteor would cause for damage initially, however the lasting effects would be somewhat similar.

The Nuclear Fallout would impact the entire globe. similar to how a large meteor strike would cause drastic climate change. It isn't the impact that kills life, its the effects afterwards that does life in. All out nuclear war, and a large meteor are similar in this way.. Yes, however, a meteor would be more devastating. But preparing for nuclear war is a good way to prepare ourselves for such an event.

Humans will survive both however, we are just that evolutionary prepared for drastic adaptation. Along with other successful plants and organisms, such as rodents, arthropods, bacteria and viruses.

dalem · 12-14-2007, 00:19 AM

I agree it would take a Shoemaker-Levy equivalent for us to completely lose civilization. But such objects ARE out there.

-dale

Capt Bluesman · 12-26-2007, 17:37 PM

I opened this thread expecting a tasty recipe. I am most disapointed.

dalem · 12-26-2007, 17:44 PM

Quote:

Originally Posted by Capt Bluesman

I opened this thread expecting a tasty recipe. I am most disapointed.

O great lady, there are some recipe threads scattered about. But none for dinosaur dishes.

-dale

**Parihaka** · 12-26-2007, 19:53 PM

Quote:

Originally Posted by Capt Bluesman

I opened this thread expecting a tasty recipe. I am most disapointed.

Apologies oh she who must be obeyed, but you will find many fine recipes in this thread
A butter cookie with nuts
: Parihakabowsobsequiously:

**TopHatter** · 12-26-2007, 20:42 PM

Quote:

Originally Posted by Capt Bluesman

I opened this thread expecting a tasty recipe. I am most disapointed.

Don't feel bad, I misread the title as "Great Breasts Peppered From Space"

Hence my reaction of "WTF?"

Blademaster · 12-26-2007, 20:50 PM

That was a freudian slip, wasn't it?

12-13-2007, 09:07 AM	#3 (permalink)
Desdemona Patron Join Date: 10-08-07 Location: God Bless Ohio, USA Posts: 202 Country:	I kind of like the varying hypothesis of extinction. It reinforces my thoughts that global warming is far greater impacted by things we have no control over. __________________ "We are the people our parents warned us about." Jimmy Buffet

12-13-2007, 12:57 PM	#5 (permalink)
RustyBattleship *Defense Professional* Join Date: 01-12-06 Location: Long Beach, CA Posts: 2,724	It sometimes seems like old hat every time a science show has another version of asteroid strike. However, this last one is a shocker. It indicates an irradication of large animals (Mammoths, etc.) and the Clovis people by a northern asteroid strike about 13,000 years ago. Yet other fossil evidence shows a similar strike about 30,000 years ago. I think we should keep a stockpile of thermo-nukes around with rockets and probes that can land on one of these incoming asteroids to whack it out of collision course or break it up altogether. Yes, I said land on it. I was watching one show where the "expert" scientists think it should be a proximity blast several miles from the asteroid. Ummm, and what do you think is out there to transfer the shock wave? Space is rather void of a compressible, shock transferring atmosphere. Oh. One other thing that worries me. The last time we tracked an asteroid that could have caused major damage was AFTER it passed BETWEEN us and the Moon. I think we need to keep our targeting RADAR looking for incomings rather than "Whew. That was close". __________________ Able to leap tall tales in a single groan.

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12-13-2007, 01:10 AM	#2 (permalink)
dalem Lord High Hullabalooster *Senior Contributor* Join Date: 11-23-04 Location: Columbia Heights, MN Posts: 8,323 Country:	I hate these constant efforts to tie in possible impacts with extinctions. -dale

12-13-2007, 17:49 PM	#6 (permalink)
Canmoore *Senior Contributor* Join Date: 05-18-06 Location: Canada Posts: 1,331 Country:	I think humans would survive a meteor strike. Hell, we were bent on surviving nuclear war for 40 years. Whats the difference between that and surviving a meteor strike?

12-14-2007, 00:19 AM	#10 (permalink)
dalem Lord High Hullabalooster *Senior Contributor* Join Date: 11-23-04 Location: Columbia Heights, MN Posts: 8,323 Country:	I agree it would take a Shoemaker-Levy equivalent for us to completely lose civilization. But such objects ARE out there. -dale

12-26-2007, 17:37 PM	#11 (permalink)
Capt Bluesman Bluesman's beloved *Military Professional* Join Date: 12-23-07 Location: Vacaville, CA Posts: 144 Country:	I opened this thread expecting a tasty recipe. I am most disapointed.

12-26-2007, 20:50 PM	#15 (permalink)
Blademaster Military Enthusiast *Senior Contributor* Join Date: 08-15-03 Posts: 3,050	That was a freudian slip, wasn't it?

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