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Evo
#37
Oct1-11, 02:52 PM
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There hasn't been a reversal for ~780,000 years.

Thread locked pending moderation and moved to earth sciences.

Also thanks to Andre, the Gothenberg "flip has indeed been debunked, it was a bad sample. It also doesn't coincide with any extinction.

The Gothenburg "Flip"
In the case of the Gothenburg "flip," which Hancock (1995) misidentified as a "magnetic reversal, FOG again provided a poorly researched analysis. The still unproved Gothenburg "flip," if real, was a rapid and brief change of magnetic field that occurred about 12,350 BP. It was not a real magnetic reversal. The last true magnetic reversal occurred 730,000 years in the change from the reverse polarity of the Matuyama Magnetic Epoch to the normal polarity of the Brunhes Magnetic Epoch. The Gothenburg "flip," as proposed by Morner (1971) and reported by Anonymous (1972), is more properly called a "magnetic excursion" because the Earth magnetic field did not reverse itself permanently but briefly changed without complete reversal over the period of a few years. For this event to represent Earth crustal displacement, the Earth's crust at about 12,350 BP would have to shift 180 degrees one direction and shift another 180 degrees back to its exact original position within the space of a few years. The timing of the Gothenburg "flip" fails to match any proposed Earth shift by either Hapgood (1970) or Flem-Ath (1997) in either timing or amount of predicted shift. Also, the validity of the Gothenburg excursion has been challenged by a number of studies which repeated have failed to detect its presence in a number of paleomagnetic records that cover 12,350 BP. At this time there is considerable question that the Gothenburg excursion even occurred and, in fact, the result of soft sediment deformation (Jacob 1994:103-107).
continued...

http://www.intersurf.com/~chalcedony/FOG10b.html

See existing thread http://www.physicsforums.com/showthread.php?t=525126