Chronology of ice retreat over Gaspesie: New evidence and implications.

Chronology of ice retreat over Gaspesie: New evidence and implications. The general chronology of ice retreat in the Lower-St. Lawrence and Gaspe Peninsula regions is drastically changed by new AMS dates on the first terrestrial plant macrofossils recovered from postglacial sediments from a dozen lakes throughout the area. The dates indicate that most of the Gaspe Peninsula was ice-covered until 10 500-10 000 year BP except along coasts, particularly the northern coast, where ice retreat on land dates back over 12 500 year BP in places. Final deglaciation occurred in the Murdochville area at around 9500-9000 year BP. The implied chronology of ice retreat is now in accordance with that from the Maritimes, especially with respect to active ice masses during the Younger Dryas episode. This finding has important implications for the modelling of ice retreat and for climatic reconstructions, as well as for accessibility of land to plant, animal and human populations.