Monday, January 05, 2009

Wow. Nano-diamonds found in a layer of sediment suggest mammoths were killed by a comet-impact.

Minuscule diamond fragments found in a sediment layer dating from thousands of years ago are bolstering the theory that a catastrophic comet impact wiped out many forms of life in North America, including what are thought to have been the first human settlers of the continent, the so-called Clovis people. The nano-diamonds are buried at a level that corresponds to the beginning 12,900 years ago of the Younger Dryas, a 1,300-year-long cold spell during which North American mammoths, saber-toothed cats, camels and giant sloths became extinct. The Clovis culture of American Indians also appears to have fallen apart during this time [Reuters].

Apparently a thick fur coat is not heavy enough for a nuclear winter, eh?


MiniKat said...

The lack of enough food to fuel a mammoth's saggy self is more the issue. Limited resources for any large critter is a death sentence. They were one of the largest things tromping around the continent at the time, and they needed a lot of fuel.

What tugs at my brain is the lack of an impact crater. I've seen the computer models run that postulate the comet hit an ice sheet, thus explaining away the absence of a great bit hole. But I would love to see more evidence.

phlegmfatale said...

I see your point, but what about the impact craters beneath large bodies of water like that of the Yucatan peninsula which is thought to have been the iridium bringer spelling the end of the dinosaurs? No telling what lurks in the depths...

MiniKat said...

Actually I've studied sediment from the Yucatan. It's quite interesting. Also if you can get your hands on satellite images of the Yucatan and even Chesapeake Bay you can see evidence of impact craters outlined under the water.

Specifically about the Yucatan and iridium, there's a great book called "T Rex and the Crater of doom" written by Alvarez. It's a great read and details the evidence used to support the impact hypothesis. Of course the title alone was enough to get me to read it years ago. How can you resist a crater of doom? ;-)

NotClauswitz said...

I love archaeological history! IMO another place they should look for iridium sediments is in the Bay of Bengal - it has been in-filling with sediments washed down from the Himalayas for the last 20,000 years and getting shallower than Galvaston.
When the tide is out you can drive out on it for mile with a jeep.

MiniKat said...

I got to read the article in "Science" magazine today. I think they are onto something but they haven't presented enough evidence.

They only referenced three areas that they took samples from and only two of those had iridium in them.

What I would love to see are sampling from more locales and then some correlation with the pollen and other plant remains from the Younger Dryas Boundary. Something like an impact occurs and it messes with the growing cycles and the botanical zones. The pollen would tell us for sure if something wonky happened.

phlegmfatale said...

MiniKat - Crater of Doom? Fabulous!

DirtCrashr - it IS fascinating. Wow - a mile? jeepers.

MiniKat - maybe they know more but don't want to tip their hand until they gather more data? Still, speculating and exploring possibilities is fun and interesting.