[meteorite-list] YD impacts, or something else? And do comets have metal cores?

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Mon, 30 Nov 2009 15:42:28 -0800 (PST)
Message-ID: <297954.42616.qm_at_web36902.mail.mud.yahoo.com>

Hi all -

Dr. Firestone was and is a nuclear chemist, not a trained archaeologist, and the problem that he faced was an unusually young series of 14C dates:

http://abob.libs.uga.edu/bobk/nuclear.html

Similar anomalies may be showing up in the Appleton Lake sediments, giving the wide spreads of sediment dates.

Daren Garrison came up with this rather scathing synopsis of some of Firestone's earlier hypothesis as he tried to work his way through this 14C dating problem and other data that came in:

"Okay, a review-- so far this impactor has been a 500 mile wide snowflake from the atmosphere of a supernova hitting at hundreds of kilometers per second. It has been an airburst over ice leaving no crater. It has left craters deeper than Death Valley in the Great Lakes. It has caused golden showers and a rain of diamonds that lasted for months. It shotgun-blasted iron particles into the tusks of mammoths. It has been a comet. It has been a chondrite...

"So, to sum it up, this 500 mile 10 mile very low-density metal and stone filled comet-asteroid supernova-produced lunar snowflake that struck at hundreds of kilometers per second did and didn't produce impact craters and left no marks except for the Great Lakes and thousands of very shallow overlapping, highly oblong pits exactly like craters from an impact event except for craters from an impact event rarely being very shallow, overlapping, highly oblong pits.

"It killed off all the lost Ice Age fauna at once, except for all of the Ice Age fauna which went extinct at different times in different locations and spread out over thousands to tens of thousands of years (in some spots pretty darn well timed with the establishment of human populations, coincidence or no.) Oh, and somehow a supernova is still involved.

"That isn't refining an idea-- that is throwing everything you can think of
against the wall and hoping that some of it sticks."

In essence, Firestone first proposed that the neutrons causing the anomalous 14C dates came from a supernova, and still does hold to that. But he also views the blast of that supernova as an injection mechanism for comets. (And previously asteroids, but these iron asteroid impacts are now known not to be from 10,900 BCE, but from 2 seperate earlier events.)

As far as the metals go, did they come from rock that was impacted or from a large comet's core?

Firestone has also considered that a weakening of the Earth's magnetic field may be involved in the higher than normal neutron flow and higher 14C production.

But there is another possibility here, one that was explored by Dr. Libby when he first was working with 14C. That is that neutrons are released in hyper-velocity comet impacts - Libby tried to find data for this from the Tunguska impact, but it was too small to be conclusive. To my knowledge, so far no funding has been provided to check for the release of neutrons at known asteroid impact sites.

The only contribution I can make to this discussion is to point out that some of the first peoples appear to have remembered comet impacts, and that many quarries were "abandoned" at about 10,900 BCE. "Later" mega-fauna remains showing survival after 10,900 may be because of the higher 14C produced.

In summary, the problem of the anomalous 14C dates still remains. While one might attribute them to careless handling, contamination, or equipment failure, their clustering suggests that something happened...

E.P. Grondine
Man and Impact in the Americas






      
Received on Mon 30 Nov 2009 06:42:28 PM PST