Re: Large animal extinctions caused by early man

Wallace Neslund (
Tue, 02 Jul 1996 20:43:15 -0700

Karen wrote:
> < really big cut>

> I agree with P3 that your idea needs supportive data. And if there
> was some huge crash wave Tsunami style, why would the big animals not
> survive, but the smaller bipedal ones survive?
> --
> Karen
> >:P3

Sorry to cut out so much, but this was a very long post, and its
still available. I have a couple of comments to make about the
above. There is a mechanism to explain some massive flooding at
the start of the Holocene in N. America. The receeding and
melting of the N. A. glacial ice cap caused giant lakes to be
formed in the interior of the continent, lakes held in place by
ice dams from the reecding glaciers. Several times these lakes
broke the ice dams and cascaded to the see in massive floods. The
Bad Lands of the Pacific Northwest are a result of their draing
to the West. National Geographic had a very well photographed
article about this last year or so. There was also a similar
glacial lake in the Minn.-Wisc. When it catastrophically drained
into the Great Lakes and thence into the Atlantic Ocean it is
suspected of interupting the north Atlantic conveyer (Gulf
Stream), causing the reversal of the heat flow north, and
instituting a mini ice age in Europe.

These catastrophic water flows happened repeatedly during the end
of the ice age about 10-12 kya. There is no evidence I know of of
a missisippi valley flood, but if one went east and one went
west, maybe one went south as well.

Why would animals be washed away and not humans? If the settelers
of N. A. followed the example of their European counterparts,
they would have made their camps on top of hills. This allowed
them to track and follow the game herds. The herds would have
traveled the lowlands where the grazing is easier.

This is, of course, simplistic, and only explains the
death of animals that would be in the direct path of the lake
floods. If the animals were already under stress from climate
change, though, and the arrival of man was putting an extra
burden on their numbers, the repeated floods might be enough to
stress them beyon recovery. I also recall that there was some
massive ash fall from the Cascade volcanoes about this time, but
I can't remember the dates. I do recall that it was a very good
NOVA show and there is now a museam in Neb. or thereabouts
dedicated to the excavation.


God knows, I don't. - Thomas Aquinas

He's some dumb, he not only doesn't know anything,
He doesn't suspect anything. - unknown