"There's the Gothenburg magnetic reversal of 11,500 years ago, when the 
mammoths went extinct."

This is the approximate date of end of paleolithic; the date caught my 
eye while reading: 
www.evolutionaryleaps.com/Magnetic_reversal_may_now_be_in_progress-BGS.htm
after following the link from http://www.iceagenow.com

They seem to think that we are due for another one any time now, or that 
it is already happening.

William