CGRG Bibliography of Canadian Geomorphology
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Author : Godfrey, J; Lian, O.B.; and Brennand, T.A.
Date : 2007.
Title : Dating sediments in the Bowmanville Bluffs: A key to firming up the interpretation of Quaternary environmental change in the Lake Ontario basin.
Publication : Annual Meeting, Western Division of the Canadian Association of Geographers, March 8-10, 2007. University College of the Fraser Valley, Abbotsford, British Columbia.
Issue : Program and Abstract Volume.
Page(s) : 27.
Abstract
Our knowledge of Quaternary environmental change in the Lake Ontario basin has, in large part, been based on reference sections in the Toronto area. These sections contain a glacial lake assemblage known as the Thorncliffe Formation, believed to be of middle Wisconsinan age (marine oxygen isotope stage (MIS) 3) based on radiocarbon ages from detrital organics, and thermoluminescence ages. Sediments to the east of Toronto, in the Bowmanville bluffs, contain a similar glacial lake assemblage, the Clarke Beds, that has been lithostratigraphically correlated to the Thorncliffe Formation; the Clarke Beds have not been dated. In this paper we report on 13 optical age estimates for the lower Clarke Beds, sampled from Lake Ontario bluffs between Port Hope and Newcastle. Using rudimentary optical dating experiments we can clearly show that the Clark Beds must have been deposited during MIS3. Furthermore, consistency between the optical ages suggests effective grain zeroing prior to subaqueous deposition. Optical ages from the lower Clarke Beds sediments confirm their lithostratigraphic correlation to the Thorncliffe Formation. This chronological control will facilitate interpretations of regional environmental change in the Lake Ontario basin.
Bibliography of Canadian Geomorphology