Quaternary Stratigraphy and Events in Southeastern Quebec
B. C McDONALD and W. W SHILTS
Geological Survey of Canada, Ottawa, Canada
Quaternary stratigraphic units have been mapped in the Appalachian region of southeastern Quebec, and formal stratigraphic names for these units are proposed. Evidence exists for four separate glacial phases, the last three of which are represented by tills. The three tills, from oldest to youngest, have been named Johnville, Chaudiere, and Lennoxville, respectively. Stratified sediments interbedded with the tills record significant nonglacial intervals between each of the glacial phases. It is suggested that the last three glacial phases are of Wisconsin age and that the Lennoxville Till represents the entire late Wisconsin. Ice-flow directions were determined using dispersal shadows (indicator trains), till fabrics, and striations. Johnville ice flowed from the northwest; Chaudiere ice flowed initially from the northeast, but later from the northwest; Lennoxville ice flowed from the northwest. Late Wisconsin glaciers did not flow northward or northwestward into Quebec from New England. Pre-Johnville stratified sediments probably record pre-Wisconsin deposition. The Massawippi Formation, recording the nonglacial interval between the Johnville and Chaudiere glacial phases, may correlate with the St. Pierre peat beds of the St. Lawrence Lowlands. The Gayhurst Formation, recording the nonglacial interval between the Chaudiere and Lennoxville glacial phases, may correlate with some of the Port Talbot interstadial sediments of southern Ontario. The Quebec Appalachians were finally deglaciated by about 12,500 C14–yrs B.P.
