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Old Jan 6th 2009, 01:36 PM
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andrewl andrewl is offline
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Default The Great Pleistocene Die-Off

For those not familiar with this controversial issue i will quickly summarize.

About 13K years ago all the big mammals on the north american continent went extinct. The woolly mammoth, the mastadon, the sabre tooth cat, the giant armadillo, horses, etc...

In the world of science and humanities there has been a long and lively debate over what the cause of this extinction was. This debate is generally divided into two camps. One camp says climate change killed them (a brief ice age, the younger dryas). And another camp says overhunting by paleoindians who arrived on the scene at roughly the same time was what killed them.

Other scientists lean towards a combination of climate change and hunting.

Then, there was a asteroid impact theory. This theory now has some very strong evidence in the form of nanodiamonds located at various sites across north america. Essentially there is a thin layer of diamonds that could only have been cerated by extreme heat and pressure (i.e., a massive impact event), this layer was fromed approximately 12,900 years ago. This new evidence explains quite a bit.

It explains the pleistocene die-off, the drop in population of the clovis people (paleo-indians), and it offers an explanation for why the younger dryas ice age occured.

Here is a link to the story:

http://www.sciam.com/article.cfm?id=...2900-years-ago

Now, as someone who often likes to idealize my pre-civilized ancestors, i quite like this theory and am excited about this new evidence. I have often argued with people that not all cultures are as exploitive to the eco-system as this civilized culture is. One thing my opponents always seemed to bring up was the overhunting of the great north american mammals by the earliest inhabitants of this continent. Its always been a challenging argument for me because the climate change theory never made much sense (these mammals lived through various cycles of climate change). But the over-kill theory never made much sense either given what we know about many tribal cultures and also the fact that many of these mammals coexisted with humans on other continents and were never killed off.

It seems now that neither camp was at all correct.

BTW, i am certainly not an expert on this issue so any corrections are welcome.

Andrew
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Old Jan 8th 2009, 06:46 PM
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Default Re: The Great Pleistocene Die-Off

Interesting article - and I am generally familiar with the topic.

Quote:
Originally Posted by andrewl View Post
It seems now that neither camp was at all correct.
I think that's a bit premature.

First of all, the article headline and sub-head both are couched in exploratory or non-assertive terms...

Quote:
Originally Posted by Article
Did a Comet Hit Earth 12,000 Years Ago?

Nanodiamonds found across North America suggest that major climate change could have been cosmically instigated.
This merely adds another possible option of interpretation to the given data. It does not show that other existing theories on the topic are mistaken.

Secondly, I'm a skeptic with the variations in our geological dating systems. Since I first learned about "Lucy", her date has been moved by a million years (1.5-1.75 mya has shifted to 2.5-2.75 mya over the course of about 15 years of my observation). This is a fairly routine date-change. As our knowledge (or guesses) get better, our interpretation of the data changes. I fully expect the dating on 'Lucy' to break the 3 mya mark if it hasn't already. The point being that arguments based on precise geological dating are subject to dating revisions over time.

As for your particular interest in 'exonerating' the ancestors of NA Indians of environmental degradation in the slaughter of large mammals in NA, the article cites only a single 'possible' piece of evidence of one site where diamonds were found 'above' a mass-mammal slaughter location (suggesting it comes after in time). That's a thin reed. More data on this is clearly needed before one can consider this theory dominant.

Btw, this evidential theory (if correct) is still unlikely to exonerate the Arizona Indians who clear-cut their valley into a desert (much like the evidence for the Easter Island stone-carvers). These examples still exist regardless of how the comet theory plays out as examples of typically human destructive behavior over the environment (independent of 'capitalism' as it were).
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