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The Mystery Interval

26 August 2012

At http://geology.gsapubs.org/content/early/2012/08/08/G33279.1.abstract … is an abstract of a paper published August 2012 in Geology journal, 'Seasonal Laurentide Ice Sheet melting during the Mystery Interval, 17.5-14.5ka' and begins by saying the last deglaciation (the end of the last Ice Age) was interrupted by two stadials (cold episodes). The so called 'mystery interval' at 17.5 to 14.5 thousand years ago, otherwise known as the Oldest Dryas Period or Heinrich One) and the Younger Dryas, at 12.9 to 11.7 thousand years ago (mysteriously leaving out the Older Dryas event, shortlived but dividing the two warm phases between 14.5 and 12.9 ka).

So, we have the Oldest Dryas period defined as a mystery stadial, or a cold period at the 'end' of the Ice Age when in fact the evidence should be of warming – perhaps this is the mystery. Little actual investigation, in recent years, has been publicised on this mysterious stadial, research has tended to concentrate on the Younger Dryas stadial, nearer in time and more readily isolated. The current research is based on meltwater flow into the Gulf of Mexico via the Mississippi watershed and is an attempt to understand the process of melting the northern ice sheet (the Laurentide ice sheet in geological parlance). What they found is there were three episodes of rapid melting between 17.5 and 12.9 ka – and it then stopped. At the start of the Younger Dryas (it also looks like it stopped during the Older Dryas but this is conjecture). It is thus assumed, by the researchers, by calculated guesswork, that the ice continued to melt seasonally (in summer months) but the water flowed not via the Mississippi but by another route, directly into the North Atlantic (through the St Lawrence river system for example). However, the Younger Dryas was cold, a stadial (near Ice Age conditions, in winter if not in summer) – why would there be continuous melt? This brings us to the real mystery – unmentioned. The Oldest Dryas was likewise a stadial, a very long one at that, but is juxtaposed against the Late Glacial Maximum (Ice Age followed by stadial) and yet the northern ice sheet was in the process of melting as meltwater was flowing into the Gulf of Mexico. This means the glaciers and the snowline was in retreat – even during a stadial. This might be consistent with Pole Shift. Is it consistent with the consensus model central to the premise of the Ice Ages?

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