A large ice sheet still covered almost all of Maine and eastern New England until ca. 15 cal ka BP, reaching south of 45 degrees S, despite rising summer insolation intensity and major ice recession elsewhere outside the North Atlantic region. Furthermore, the well-studied moraine belt along eastern coastal Maine, including the prominent Pineo Ridge delta/moraine complex and Pond Ridge moraine, indicates repeated readvances and stillstands between ca. 16 and 15 cal ka BP. This moraine belt reflects a considerable ice sheet response over eastern North America during this time period, coeval with the latter half of the European Oldest Dryas period. Moraine deposition was concurrent with reduction or elimination of North Atlantic meridional overturning, starting with the earlier onset of peak IRD and Heinrich Event 1 (HE-1). The existing C-14 chronology suggests that the coastal moraine belt and the persistence of the ice sheet until similar to 15 cal ka BP was a response to the severe cooling of the North Atlantic region after similar to 17 cal ka BP. (c) 2007 University of Washington. All rights reserved.
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