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Sangamonian and early Wisconsinan events in the St. Lawrence Lowland and Appalachians of southern Quebec, Canada

Michel Lamothe, Michel Parent and William W. Shilts
Sangamonian and early Wisconsinan events in the St. Lawrence Lowland and Appalachians of southern Quebec, Canada (in The last interglacial-glacial transition in North America, Peter U. Clark (editor) and Peter D. Lea (editor))
Special Paper - Geological Society of America (1992) 270: 171-184

Abstract

In the St. Lawrence Lowland of southern Quebec, an early Wisconsinan glacial advance deposited the Levrard Till. This glacial event, known as the Nicolet Stade, is tentatively correlated with marine oxygen-isotope stage 4. Radiocarbon and thermoluminescence ages bracket the Nicolet Stade between 90 and 70 ka. This advance was preceded and followed by periods of free drainage during which were deposited the Lotbiniere Sand and St. Pierre Sediments, two nonglacial units dated at or beyond the limit of the radiocarbon method. Available evidence suggests that the Deschaillons Varves were deposited ca. 80 ka in a large glacial lake that was impounded in front of the Laurentide Ice Sheet as it advanced up the St. Lawrence Valley. In the Appalachian Uplands, fluvial and lacustrine sediments of the Massawippi Formation were probably deposited at the end of the Sangamonian Interglacial. These sediments underlie the Chaudiere Till, a unit in which the occurrence of distinctive lithological indicators is taken as evidence that a regional episode of westward to southwestward ice flow prevailed at the onset of the last glaciation. The proposed paleogeographic reconstruction suggests that the development of an independent ice cap in the northeastern Appalachians played a key role during the early part of the Wisconsinan Glaciation in southern Quebec. This independent ice mass flowed southwestward across the Appalachian Uplands of southern Quebec and eventually coalesced with the Laurentide Ice Sheet, which was advancing up the St. Lawrence Valley.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 270
Title: Sangamonian and early Wisconsinan events in the St. Lawrence Lowland and Appalachians of southern Quebec, Canada
Title: The last interglacial-glacial transition in North America
Author(s): Lamothe, MichelParent, MichelShilts, William W.
Author(s): Clark, Peter U.editor
Author(s): Lea, Peter D.editor
Affiliation: Universite du Quebec a Montreal Department des Sciences de la Terre, Montreal, QC, Canada
Affiliation: Oregon State University, Department of Geosciences, Corvallis, OR, United States
Pages: 171-184
Published: 1992
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0813722705
References: 43
Accession Number: 1993-006648
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: chart, sects., strat. cols., sketch maps
N33°00'00" - N47°30'00", W87°00'00" - W67°00'00"
N45°00'00" - N63°00'00", W79°00'00" - W57°00'00"
Secondary Affiliation: Bowdoin College, USA, United StatesGeological Survey of Canada, CAN, Canada
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1993
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