Supernova led to Mammoth extinction?

Andre · #1 (**permalink**) 06-November-2005, 12:05 PM

Richard Firestone, a nuclear expert, has been working for years now on the hypethesis that the North American megafauna (mastodons, woolly mammoths etc) went extinct due to a supernova.

He presented this idea on two recent congresses so it's getting some media coverage now:

http://www.lbl.gov/Science-Articles/...xtinction.html

Quote:

BERKELEY, CA – A distant supernova that exploded 41,000 years ago may have led to the extinction of the mammoth, according to research conducted by nuclear scientist Richard Firestone of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).

(...)

Firestone and West believe that debris from a supernova explosion coalesced into low-density, comet-like objects that wreaked havoc on the solar system long ago. One such comet may have hit North America 13,000 years ago, unleashing a cataclysmic event that killed off the vast majority of mammoths and many other large North American mammals. (...) It has long been established that human activity ceased at these sites about 13,000 years ago, which is roughly the same time that mammoths disappeared.

They also found evidence of the supernova explosion’s initial shockwave: 34,000-year-old mammoth tusks that are peppered with tiny impact craters apparently produced by iron-rich grains traveling at an estimated 10,000 kilometers per second. These grains may have been emitted from a supernova that exploded roughly 7,000 years earlier and about 250 light years from Earth.

“Our research indicates that a 10-kilometer-wide comet, which may have been composed from the remnants of a supernova explosion, could have hit North America 13,000 years ago,” says Firestone. “This event was preceded by an intense blast of iron-rich grains that impacted the planet roughly 34,000 years ago.”

I'm familiar with evidence. It's there. One element in particular is striking, the unexplained atmospheric radio-active carbon14 spikes in those periods (the last one actually 12,770 years ago) suggesting that something indeed was going on.

My questions:

What would the experts think of such a mechanism?

Is there a known supernova that matches the possible range of parameters and that could be close enough for causing all of these phenomenons?

***
Off the record -not astronomic- , but just in case somebody wondered: the continental Siberian mammoths seemed totally unaffected by the 13,000 years event and continued to thrive at least another 1500-2000 years, the oldest dated fossils being around 11,200 calendar years. After that, a relict population survived even longer on Wrangel island, the youngest fossils being dated some 4000 calender years ago. So whatever happened, Firestone's event was not responsible for the complete late-Pleistocene megafauna extinction.

Dragon Star · #2 (**permalink**) 06-November-2005, 07:20 PM

I am not sure, but aren't most mammoths found frozen to death with food still in their mouths?

Or was that just used as historical proof for the movie "Day After Tomorrow?

Andre · #3 (**permalink**) 06-November-2005, 07:47 PM

That's an extreme persistent fairy tale that can be debunked in a number of ways. We have a lot of detailed reconstructions now. Very fascinating but unfortunately rather off thread. I'd hoped to discus the possible physical impact of a nearby supernova on life on Earth and learn whether or not this could be a feasible scenario.

Crum · #4 (**permalink**) 06-November-2005, 11:37 PM

Quote:

They also found evidence of the supernova explosion’s initial shockwave: 34,000-year-old mammoth tusks that are peppered with tiny impact craters apparently produced by iron-rich grains traveling at an estimated 10,000 kilometers per second. These grains may have been emitted from a supernova that exploded roughly 7,000 years earlier and about 250 light years from Earth.

Iron-rich grains survived 10,000 kilometer per second entry into our atmosphere and peppered the tusks of mammoths? Does anybody else see a problem with this? And where are the other "peppered" relics of this era? Or did these meteorites have some preference for mammoth tusks?

Nowhere Man · #5 (**permalink**) 07-November-2005, 01:45 AM

This is also being duscussed in this here thread.

Fred

aurora · #6 (**permalink**) 07-November-2005, 04:29 AM

Amazingly selective supernova. Wonder why caribou and musk oxen are immune?

tracer · #7 (**permalink**) 07-November-2005, 04:24 PM

Quote:

Originally Posted by Crum

Iron-rich grains survived 10,000 kilometer per second entry into our atmosphere and peppered the tusks of mammoths? Does anybody else see a problem with this?

Maybe by "iron-rich grains", they meant "superheated balls of plasma that happen to be rich in fully-ionized iron atoms"?

Tunga · #8 (**permalink**) 07-November-2005, 06:25 PM

I thought the research paper was interesting especially the Carbon14 spikes. Carbon 14 is produced by collisions of very high speed nuclear particles (GCRs) with nitrogen atoms in Earth's atmosphere, converting the nitrogen into a radioactive form of carbon. (Sounds like alchemy)
http://hyperphysics.phy-astr.gsu.edu...ar/cardat.html
Supernovas generate an explosion of very high energy GCRs. Nearby supernova events within 2,000 light years from Earth can produce a spike in Carbon 14 on Earth. Other recent research papers have been correlating carbon 14 spikes observed in ice cores to supernova events.

AK · #9 (**permalink**) 11-November-2005, 03:35 AM

Quote:

Originally Posted by Crum

Iron-rich grains survived 10,000 kilometer per second entry into our atmosphere and peppered the tusks of mammoths? Does anybody else see a problem with this? And where are the other "peppered" relics of this era? Or did these meteorites have some preference for mammoth tusks?

I'm more struck by the allegation that a comet 10km in diameter is the culprit, yet only the North American/South American megafauna were affected? With an impactor that large you're looking at something more like global sterilization than local extinction of only large mammals...

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode