Surficial geology, Great Island-Seal River, Manitoba / [by] M.S. Trommelen and J.E. Campbell. : M183-1/42-2011E-PDF

"Northeast Manitoba is mantled by glacial and post-glacial sediments, with scarce bedrock outcrops. Past ice-flow reconstructions in northern Manitoba suggest that the region has been covered at least twice by ice from the Keewatin sector, and at least three times by ice from the Labradorean sector (Dredge et al., 1986; Klassen, 1986; Dredge and Thorleifson, 1987; Boulton and Clark, 1990; Dredge et al., 1990; Dredge and Nixon, 1992; Kaszycki et al., 2008). This map builds on previous 1:250,000 surficial mapping completed in the 1980's (Dredge and Nixon, 1981, 1982). The northern part of the study area is characterized by extensive swaths of bouldery drumlinized and pristine (non-drumlinized) Rogen moraine ridges alternating with swaths of streamlined terrain. The remaining area is characterized by bedrock topography draped by a mix of till blankets and till veneers. Long, large eskers are present throughout the area, at roughly 18 km intervals. Where the eskers are located below approximately 200 m asl, they have been partially eroded by lacustrine and/or marine waters. Below 150 m asl, the eskers exist as washed, low-lying sand and gravel blankets rather than ridges. A mix of organic blankets and marine sediment is present in the eastern portion of the study area, predominantly below150 m asl. The study area has, in part, been wave-washed by either or both the postglacial Tyrrell Sea and Glacial Lake Agassiz or other smaller disconnected glacial lakes. The marine limit in the study area is around 180 m asl. Field data were obtained by helicopter-assisted ground-truthing in 2009 and 2010. Further description of map units, with photos, can be found in Trommelen and Ross (2009) and Trommelen et al. (2010). Field data are available in McCurdy, M.W, et al. (2011)"--Abstract.

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