CGRG Bibliography of Canadian Geomorphology
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Author : Christie, D.G.J.; McCarthy, F.M.G.; Medioli, B.E.; Brooks, G.R.; Tiffin, S.H.; and Blasco, S.M.
Date : 2007.
Title : The camoebians record climate-driven closed basin conditions in Georgian Bay correlated with the 8.2 k event.
Publication : CANQUA Ottawa 2007. Canadian Quaternary Association Conference, June 4-8, 2007. Carleton University, Ottawa, Ontario, Canada.
Issue :
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Abstract
The early Holocene in the Great Lakes region is marked by a dominance of pine pollen, recording the relatively dry conditions that produced the regional pine zone at mid-latitudes in eastern North America. Superimposed on this long, relatively dry interval, is the 8.2 k event, that was first identified in the Greenland ice core, however its identification in the Great Lakes has been disputed. Trees can respond to rapid climate change within several decades, but protist populations with rapid generation times respond within months, providing better resolution to investigate this short event. The pollen assemblage in 2 sediment cores from Muskrat Bay, in the lower French River area, record deposition during pine zones 2a and 2b, i.e some time between ~9800 and 7500 cal. yr. B.P.). Core MUS6 was also studied for thecamoebians (testate amoebae), identifying a centropyxid-dominated assemblage spanning over 1 m of the 4 m-long core, around the pollen zone 2a/2b boundary. Centropyxid-dominated assemblages were previously identified spanning the pollen zone 2a-2b boundary in other cores throughout Georgian Bay, from Tobermory to Severn Sound. We interpret this assemblage as recording slightly saline, closed basin conditions during the late Lake Hough phase, and we attribute the rapid onset of this major limnological change to additional climate forcing associated with the 8.2 k event.
Bibliography of Canadian Geomorphology