Could a Supernova Have Killed Off Mammoths?

[Andre]

Rich 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://weblog.physorg.com/news3399.html
http://www.lbl.gov/Science-Articles/Archive/NSD-mammoth-extinction.html

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.

We have discussed some of this briefly here but Vela-X does not seem the correct candidate.

My questions:

What would our experts think of his mechanism?

Is there a known supernova that matches the dates and that could be close enough for all this?

Isn't that radio-active comet a bit fast? covering 250 LJ in 28,000 years? or was it *less than* 250LJ perhaps?


***
Off the record, the continental Siberian mammoths seemed totally unaffected by the 13,000 years event and continued to thrive at least another 1700 years, the oldest dated fossils being around 11,200 calendar years. After that a relict population survived on Wrangel island until some 4000 calendar years ago.

 

[Chronos]

I think you are on the right track. You should first start with candidate supernovas. The remnants of any near enough to have affected Earth a mere 13,000 years ago should still be very fresh. Perhaps the veil nebula [which originated about 65,000 years ago] might be worth a look, but it was a measly garden variety nova and I believe that one has been pretty much ruled out.

 

[Entropy]

Have they found tiny impact crateors in any other animals' fossils?

 

[Andre]

Not that I know of. Firestone reported at the WoE congress:

about Paleo Indian sites at Gainey MI Murray Springs AZ and Blackwater Draw NM where they discovered a layer of abundant rounded ferro magnetic particles in direct contact with mammoth fossils, Many of the particles from the Gainey site apear to be mmeteoric and shocked. The large abundance >0.1 % per weight below the black mat is remarkable...Also found was a fragment of a mammoth tusk with at least six (magnetic) micrometeorites embedded, the largest 4 mm in diameter

text summerized liberally.

 

[Bystander]

That's one biiggg supernova, depositing that much iron at a distance of 250 light years.

The dates are a bit confused, but 34ka for the "iron fall" isn't all that much different from the 50ka estimated for the Barringer impact event.