Late Wisconsinan Deglaciation and Champlain Sea Invasion in the St. Lawrence Valley, Québec

Abstract

Champlain Sea history is directly linked to Late Wisconsinan deglacial episodes. Champlain Sea Phase I (Charlesbourg Phase) began in the Québec area at about 12.4 ka. It represented a western extension of the Goldthwait Sea between remnant Appalachian ice masses and the Laurentide Ice Sheet. Further south, at about the same time, in the Appalachian uplands and piedmont, high-level glacial lakes were impounded by the ice-front during glacial retreat toward NNW: lakes Vermont, Memphrémagog and Mégantic. Lowlands of the Upper St. Lawrence and Lake Champlain valleys were progressively deglaciated and inundated by Lake Iroquois and Lake Vermont. At about 12.1 ka, these two lakes coalesced and formed a single water-body, here referred to as Lake Candona. After the Ulverton-Tingwick Moraine was constructed, this lake extended northeastward onto the Appalachian piedmont where varved sediments containing Candona subtriangulata underlie marine clays. Current data and interpretations bring into question the former concept of the Highland Front Moraine System. The invasion of the main basin, or Champlain Sea Phase II, began around 12 ka. Replacement of Lake Candona by the sea resulted in a fall of about 60 m in water levels. Champlain Sea Phase III began at the end of the Saint-Narcisse episode, at about 10.8 ka. At this time marine waters were able to enter valleys of the Laurentian Highlands where brackish or fresh paramarine basins developed.L'histoire de la Mer de Champlain est directement liée à la déglaciation du Wisconsinien supérieur. La phase I de la Mer de Champlain (Phase de Charlesbourg) débute dans la région de Québec vers 12,4 ka. Elle représente le prolongement de la Mer de Goldthwait entre l'Inlandsis laurentidien et les glaces résiduelles appalachiennes. Plus au sud et approximativement en même temps, le retrait glaciaire vers le NNW sur les plateaux et le piémont appalachiens est marqué par des moraines et les lacs proglaciaires Vermont, Memphrémagog et Mégantic; les terres basses du haut Saint-Laurent et du lac Champlain étaient progressivement déglacées et inondées par les lacs Iroquois et Vermont. Vers 12,1 ka, ces deux lacs forment par coalescence Ie Lac Candona. Après l'épisode de la Moraine d'Ulverton-Tingwick, ce lac inondait le piémont appalachien vers le NE, où des varves à Candona subtriangulata reposent sous les argiles marines. Ces données remettent en question le concept de Highland Front Moraine System. L'invasion du bassin principal (Phase II de la Mer de Champlain) débute vers 12 ka. Le remplacement du Lac Candona par la mer provoque une chute d'environ 60 m du niveau du plan d'eau. La Phase III de la Mer de Champlain commence à la fin de l'épisode de Saint-Narcisse, vers 10,8 ka; les eaux marines pénètrent dans les vallées des Laurentides et sont coalescentes à des bassins paramarins saumâtres ou non salés.Die Geschichte des Meeres von Champlain ist direkt mit Enteisungs-Episoden im spàten Wisconsin verknùpft. Die Phase I des Champlains-Meeres (Charlesbourg Phase) began im Gebiet von Québec...

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

“…2), and in the Algonquin Provincial Park in Ontario (Daigneault and Occhietti, 2006). Facies were analyzed, using the terminology and criteria outlined in Dreimanis (1976) and Parent and Occhietti (1988). Depositional environments were then established by integrating outcrop sedimentology with landform morphology.…”

“…At Cossetteville, nineteen ridges emerge locally through the marine mud-plain (Béland, 1961;Occhietti, 1977Occhietti, , 1980. The Rodrigues and Vilks (1994) and 11 000 BP from LaSalle and Shilts (1993), other ages from Occhietti (1980), Parent and Occhietti (1988) and this paper (Table I) Saint-Maurice lobe represents a local readvance of the ice front in the St. Lawrence Valley. During construction of the Saint-Narcisse Moraine, the glacial margin lay along the topographic margin between the Canadian Shield and the St. Lawrence Sedimentary Platform (Fig.…”

“…Correlation of the Saint-Narcisse moraine-building event with Younger Dryas cooling was first intuitively suggested by Lasalle (1966) and demonstrated by Hillaire-Marcel and Occhietti (1977). The moraine has since been the focus of several studies on its lateral extent (LaSalle and Elson, 1975;Occhietti, 1980;Govare, 1995;Dionne and Occhietti, 1996), on related facies and paleoenvironmental studies (Gadd, 1971;Rondot, 1974;Lamothe, 1977;Pagé, 1977;Occhietti, 1980;Parent and Occhietti, 1988), on stratigraphy (Occhietti, 1976(Occhietti, , 1980, on chronology (LaSalle and Elson, 1975;Occhietti, 1976Occhietti, , 1980Rodrigues and Vilks, 1994), and on its general significance (LaSalle and Elson, 1975;Occhietti, 1980;HillaireMarcel et al, 1981). The objectives of this article are as follows: (1) synthesize new and existing data on the geology of the Saint-Narcisse Moraine, (2) analyse the 14 C ages available and reconstruct the sequence of phases occurring during the Saint-Narcisse Event in early Younger Dryas time, and (3) present some implications of the Saint-Narcisse Event along the southeastern ice margin of the Laurentide Ice Sheet.…”

Félix: a Late Pleistocene White Whale (Delphinapterus Leucas) Skeleton From Champlain Sea Deposits at Saint-Félix-de-Valois, Québec

“…It comprises fossiliferous littoral (nearshore) sands, sandy alluvial fans and bars, stratified silts deposited in intertidal zones, as well as deltaic sediments marking a regressive phase of the Champlain Sea (Parent and Occhietti, 1988). Most of the white whale skeleton was embedded in wet siltyclay at the base of this unit.…”

Oxygen-isotope variations in post-glacial Lake Ontario

“…Lawrence River, Lake Champlain and lower Ottawa River valleys and the Lake Ontario basin (Parent and Occhietti, 1988;Rayburn et al, 2007 The supply of glacial meltwater to early Lake Ontario increased between ~13,000 206 cal [11,100 14 C] BP and 12,500 cal [10,500 14 C] BP . This 207 flow likely included discharge (overflow) from glacial Lake Algonquin (Fig.…”