There is a substantial body of evidence to support a mechanism to introduce large amounts of energy into the Earth's crust & mantle which could account for the mass extinctions of 11,000 B. C.
I subscribe to Dr. Anthony L. Peratt's theory that a High-Current, Z-Pinch Aurora enveloped the Earth and most likely has enveloped the Earth many times in the Earth's past.
Here are the peer-reviewed scientific papers which support my position:
Dr. Peratt laid out the scientific evidence for such a High-Current, Z-Pinch in two scientific papers published in the IEEE TRANSACTIONS ON PLASMA SCIENCE:
Characteristics for the Occurrence of a High-Current, Z-Pinch Aurora as Recorded in Antiquity (I & 2) by Dr. Anthony L. Peratt:http://www.scribd.com/doc/14145750/Anth ... -Antiquityhttp://www.scribd.com/doc/16839562/Char ... ntiquity-2
Dr. Peratt's reputation & understanding of plasma phenomenon both in the laboratory and in the field is unmatched.
The process Dr. Peratt describes based on his laboratory work with plasma phenomenon & field work cataloging petroglyphs is exhaustive.
Per Anthony L. Peratt:
The discovery that objects from the Neolithic or Early Bronze Age carry patterns associated with high-current Z-pinches provides a possible insight into the origin and meaning of these ancient symbols produced by man. This paper directly compares the graphical and radiation data from high-current Z-pinches to these patterns. The paper focusses primarily, but not exclusively, on petroglyphs. It is found that a great many archaic petroglyphs can be classified accoridng to plasma stability and instability data. As the same morphological types are found worldwide, the comparisons suggest the occurance of an intense aurora, as might be produced if the solar wind had increased between one and two orders of magnitude, a millennia ago.
And, it turns out that Science has observed & measured stars that have powerful electromagnetic current sheets radiating out from their equators:
From: "Spiral Dance in a Planetary Nursery"
courtesy of Sabaru Telescope They call it a "protoplanetary disc" as the star AB Aurigae seems to display the outline of it's own "ballerina skirt" also known as the heliospheric current sheet
This would seem to offer observational confirmation that aurora current sheets can exist which are orders of magnitude stronger than the present heliopheric current sheet.
And these plasma, electric current sheets would introduce huge amounts of electromagnetic energy into the Earth's crust and mantle, plus, this energy level given off by the Sun likely was repeated numerous times in Earth's past.
Regardless of the exact age of the Earth (I agree no one knows), it does appear high electromagnetic energy epochs were repeated across the great expanse of Earth's history. These epochs were catastrophic in effect and extent. There were many secondary electrmagnetic effects and phenomena. It seems quite possible that mass extinctions, including large reductions in human populations, even civilization collapsing effects could have happened.
Another physical effect would be an increased volcanism at perhaps catastraphic activity levels and, thus, large amounts of material being expelled into the atmosphere, for which there is supporting physical evidence.
Substantial re-forming of the Earth's surface is also possible due to catastrophic volcanic, earthquake, polar meling, and atmospheric electromagnetic plasma effects.
At times in Earth's history, the surface was a very inhospitable place to be. From Man's perspective, the Earth's surface would literally be in upheaval.