Quaternary stratigraphy of the Severn and Winisk drainage basins, northern Ontario

Glacial and nonglacial events in the eastern James Bay lowlands, Canada

“…2). Sedimentary sequences resembling the James Bay stratigraphy were later reported elsewhere in the lowlands of Manitoba and Ontario (Klassen 1986;Nielsen et al 1986;Dredge et al 1990;Thorleifson et al 1993; see also Thorleifson et al 1992 for a review). However, important disagreements exist regarding the direction and relative chronology of ice movements recorded by tills, with the notable difference that most regions show evidence of several iceflow directions.…”

“…There are, however, important conflicting interpretations of the HBL stratigraphy, especially regarding the number of nonglacial units and the direction of ice-flow movements deduced from the bounding glacial deposits (see review by Thorleifson et al 1992). For instance, the regional-scale northwestward ice advance associated with the buildup phase of the LabradorQuebec ice dome (c.f., Veillette et al 1999) has still to be convincingly recognized in the lowlands stratigraphy, although suggested by some workers (Prest 1963;Thorleifson et al 1993;Roy 1998). These disagreements derive primarily from the fragmentary nature of the depositional records, which is also accentuated by the difficulty in obtaining reliable absolute ages for pre-Holocene deposits, notably in the southeastern sector of HBL, a key region for the establishment of paleogeographic reconstructions.…”

“…These results strongly challenged the long-held notion of a stable LIS core over Hudson Bay during the last glaciation. This framework was significantly refined by additional analyses carried out on in situ shells from buried marine units in the James Bay basin, which showed amino acid values clustering in two distinct groups, thus arguing for the presence of at least two pre-Holocene marine invasions in this part of the HBL (Wyatt 1990;Thorleifson et al 1993). This newly identified marine incursion (the Prest Sea; Shilts and Wyatt 1988) also contradicted established stratigraphic correlations, which were largely articulated around the use of a single stratigraphic marker formed by these nonglacial deposits.…”

“…Part of the James Bay region is mantled by Paleozoic carbonates of the Hudson sedimentary platform, which lies unconformably over Precambrian crystalline rocks of the Lake Superior Province. Black and white stars show the location of buried marine units (Wyatt 1990; Thorleifson et al 1993) and the Missinaibi Formation type section (Skinner 1973), respectively. (C, D) Location of the stratigraphic sections investigated along the Harricana and Nottaway rivers.…”

Ice-Flow Chronology and Palimpsest, Long-Distance Dispersal of Indicator Clasts, North of the St. Lawrence River Valley, Quebec

“…South of the line, cross-striations record a clockwise shift in ice flow from an early southeastward flow to a late southwestward flow. While ice flow and glacial transport data toward the northwest exist north of the line, including the Hudson Bay area (Henderson, 1989;Thorleifson et al, 1993;Parent et al, 1995;Roy, 1998), data south of the line are limited to the Lake MistassiniChibougamau area, and are found mostly north of (or close to) the Grenville Front (De Corta, 1988;Cadieux, 1986;Prichonnet et al, 1984;Beaudry, 1994). The only exception is the work of Dionne (1973) who suspected the presence of Mistassini erratics in till in the Lake Saint-Jean area and later (Dionne, 1986(Dionne, , 1994 traced Mistassini erratics, up to 400 km to the southeast of Lake Mistassini, in the Tadoussac area.…”