Comet Theory field geologist's competency in question

[Forum Monk]

It does seem as if it is up to Firestone to defend his theory and his methods. He ran it up the flagpole, others have now fired on it. The ball is in his court.

I do hope that he does not try to fall back on native american folklore for "evidence." however.

I agree. The Miller McCune article does a pretty good job exposing the problems that need to be overcome if Firestone, et al hope to salvage the theory. This is the article referenced in Mr. Grondine's OP and its worth a read.

[Minimalist]

Nice to hear from you again, Monk.

[Digit]

I must admit that I find the suggestion that Clovis man wiped out the big beasts a little unlikely.

Roy.

[Minimalist]

Yes....it demands an answer to the question "why did they not 'wipe them out' in Siberia long before they got here?"

[Forum Monk]

I must admit that I find the suggestion that Clovis man wiped out the big beasts a little unlikely.

Roy.

In Australia:
http://en.wikipedia.org/wiki/Australian_megafauna

New evidence based on accurate optically stimulated luminescence and uranium-thorium dating of megafaunal remains suggests that humans were the ultimate cause of the extinction of megafauna in Australia.[3] The dates derived show that all forms of megafauna became extinct in the same rapid timeframe — approximately 47,000 years ago — the period of time in which humans first arrived in Australia. The dates derived suggest the main mechanism for extinction was human burning of a landscape that was then much less fire-adapted; analysis of oxygen and carbon isotopes from teeth of megafauna indicate sudden, drastic, non-climate-related changes in vegetation and the diet of surviving marsupial species, as well as the loss of megafaunal species. Further analysis of oxygen and carbon isotopes from teeth of megafauna indicate the arid regional climates at the time of extinction were similar to arid regional climates of today, and that the megafauna were well adapted to arid climates.

It is very possible humans wiped them out and in a short time. And notice the "burning the landscape"...it may be relevant to the discussion at hand.

[Digit]

What happened in Oz is not likely to be representative of NA, much of Oz is arid, with logically many fewer mega beasts than the much more fertile grassy plains of the northern latitudes.

Roy.

[Forum Monk]

What happened in Oz is not likely to be representative of NA, much of Oz is arid, with logically many fewer mega beasts than the much more fertile grassy plains of the northern latitudes.

Roy.

Dig, North America was experiencing a full blown ice-age. How moist and grassy do you think it was?
Check this link http://www.esd.ornl.gov/projects/qen/ne ... ERICA.html
and look at this map http://geo.arizona.edu/palynology/nam_p14k.gif

Even today, typical Canadian and U.S. upper mid-west winters can be bone dry.

[Digit]

Even today, typical Canadian and U.S. upper mid-west winters can be bone dry.

Taking your view Monk there would have been no animals for Clovis to wipe out.
South of the ice sheets would have have been grass plains, as air currents move north they would decend as they cooled, this would mean a cold southerly wind off the ice, when this met warmer air, moister air, preciptation would occur, south of the ice. If the winters were bone dry where would the ice have come from?
I have pointed out on here before that low temps means low precipitation, the moisture had to come from somewhere to freeze.

Roy.

[Forum Monk]

When Clovis people arrived there was an ice-free corridor (or so the "consensus" believes) because the climate had warmed enough to melt some areas. Obviously it warmed enough to support animals but it was anything but plush. I personally think humans crossed the Bearing Strait because they were following the migration of their dinners.

[Digit]

The Columbian Mammoth was purely NA, not Asian.
Also I have asked here before, why would people hunt a dangerous animal for more meat than they could use?

Roy.

[Forum Monk]

If you've ever eaten at a North American restaurant, you will get more food than you can eat. The tradition continues.

I recall reading that Siberian herds were nearly decimated by the time humans crossed over. Whatever they were doing with the beasts it seems logical they would have gone hunting for more. Why hunt shark just to cut off their fins? I don't know but I'll check in to it.

[Digit]

But a shark is a damn sight less likely to kill you than an Elephant, also it doesn't present you with the same sort of butchery problems.
We know that Mastodons etc were butchered, thus they weren't just killed for the tongue etc, disemboweling a Mammoth would need a a long handled, a very long handled, long bladed knife, and disarticulationg the leg bones would be, pardon the pun, a mammoth task!
Caribou et al would be much simpler, Africans have never wiped out their big beasts, they stuck to smaller, safer, prey.

Roy.

[Minimalist]

I have said this before and will repeat it now. I think it is a mistake ( however typically human ) to seek "the" cause for an event which probably was the result of multiple "causes." There were several ice sheet advances and the megafauna never died out during them. There were volcanic eruptions and the megafauna never died out from those. I'll buy part of E.P.'s theory and speculate that there were asteroid impacts ( certainly there was one c 50,000 BC less than 4 hours from where I sit) and the megafauna did not die out from them. There were humans hunting them in Siberia who did not manage to exterminate them in spite of having a lot more time to do so. One suspects there were floods, diseases and droughts as well from time to time.

But, if you take a population under stress from one or more of these events then perhaps human hunting provided the "tipping point."

[Digit]

I'm with you boo-boo!

Roy.

[kbs2244]

Note the time frame and the location.

http://woollymammoth.org/