The bulk of the animal extinctions took place between 11,000 BC and 9000 BC when there were violent and unexplained fluctuations of climate.35 (In the words of geologist John Imbrie, ‘a climatic revolution took place around 11,000 years ago.’36) There were also greatly increased rates of sedimentation37 and an abrupt temperature increase of 6–10 degrees Centigrade in the surface waters of the Atlantic Ocean.
