Synthèse lithostratigraphique et paléoenvironnements du Quaternaire au Québec méridional. Hypothèse d’un centre d’englacement wisconsinien au Nouveau-Québec

• Published in: Géographie physique et Quaternaire
• Main Author: Occhietti, Serge
• Format: Text
• Language: French
• Published: Les Presses de l'Université de Montréal 1982
• Subjects: geo; envir; Canada; Lawrence River; Ice Sheet
• Online Access: https://doi.org/10.7202/032468ar; http://id.erudit.org/iderudit/032468ar

Hypothesis of a Wisconsinan glacerization centred in Nouveau-Québec Paleoenvironments associated with the Quaternary stratigraphy of southern Québec are described, based on a review of published work. This synthesis indicates : (1) A number of contradictions together with a general lack of information with respect to the Wisconsinan chronology; (2) The apparently limited extent of Nicolet Stadial ice; (3) The existence in mid-Wisconsinan time of local caps within the Appalachian region, prior to the advance of the Laurentide Ice Sheet; (4) Regional contrasts in the sequence of events during the Trois-Rivières Stadial; (5) A late Wisconsinan reversal of ice flow direction in the Gaspé Peninsula and Beauce areas, on the northern side of the Appalachian Mountains. In the central St. Lawrence valley, paleo-environmental analysis indicates: 1) A repetition of lacustrice episodes implying periodic obstructions of the iddle estuary of the St. Lawrence River; 2) An apparent absence of marine transgressions during the Wisconsinan; 3) An apparently continuous ice cover from mid to late-Wisconsinan, in contrast with the Ontario and Nova Scotia series. These conclusions and assumptions make it possible to propose a model of glacial inception during the Wisconsinan in eastern Canada with: 1) An early and relatively southern centre of glacienzation on the Manicouagan Plateau 2) The displacement of accumulation and dispersion zones during the Wisconsinan; 3) The continuity of continental ice since at least isotopic phase 5/4. En se basant sur les travaux publiés depuis 1960, l'auteur passe en revue les séries quaternaires du Québec méridional et les réexamine d'un point de vue paléoenvironnemental. Cette synthèse confirme: (1) les contradictions et lacunes du cadre chronologique attribué au Wisconsinien; (2) l'extension apparemment limitée des glaces du Stade de Nicolet; (3) l'existence de calottes régionales sur les Appalaches, antérieures à l'englaciation de l'Inlandsis laurentidien au Wisconsinien moyen; (4) l'absence ...