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TitleThe buried component of the James Bay Winisk ice stream
AuthorVeillette, J J; Ménard, M; St-Jacques, G; Roy, M; Paulen, R C; Paradis, S J
Source 2015 p. 82-83
Alt SeriesEarth Sciences Sector, Contribution Series 20150139
PublisherCANQUA (St. John's, CA)
MeetingCANQUA 2015; St. John's; CA; August 16, 2015
Mediapaper; on-line; digital
File formatpdf
ProvinceCanada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-141.0000 -50.0000 90.0000 41.7500
Subjectssurficial geology/geomorphology; general geology; ice movement; ice retreat; ice flow; Wisconsinian glacial stage; glaciers; striations; glacial deposits; Quaternary
ProgramHudson/Ungava, Northeastern Quebec-Labrador, surficial geology, GEM2: Geo-mapping for Energy and Minerals
AbstractThe Glacial Map of Canada shows an enigmatic ice-flow anomaly (Area A) covering about 10 000 km2 in the Hearst/Kapuskasing area of northern Ontario. It consists of streamlined landforms and striations indicating ice movement toward 130º oriented at right angle to another ice flow toward 220º. Both are late glacial flows but Quaternary geologists disagree on their relative age, some argue that the east-southeast (130º) flow is the youngest and others that it is the oldest. The analysis of aerial photographs, satellite images and a detailed survey and analysis of cross-striated surfaces over an area of about 30 000 km2 within and around Area A indicates clearly that the 130º flow preceded the 220º flow. The conflicting interpretations on the relative age of the two flows within Area A are attributed mainly to the sporadic occurrence of relict striated surfaces formed by former southwestward (220º- 240º) Wisconsinan ice flows that have escaped destruction by late glacial flows with the result that the southwestward flows are older (Wisconsinan) at some sites and younger (late glacial 220º) at others relative to the 130º flow. This constraint considered with other factors like the maximum elevation reached by the youngest late glacial flow show that Area A is simply the outcropping portion of a much larger, east-southeast ice-flow system which is the southern and distal part of the Winisk ice stream (Ekwan River ice stream) located to the north, west of James Bay. The distal part of the ice stream, except for Area A, escaped detection by remote sensing methods because depositional and erosional features associated with it are masked by deposits laid down by the younger (220º) Cochrane ice flow and/or by postglacial marine and organic deposits (or were destroyed by it). Relict striations indicating ice movement toward the east-southeast crossed by striations toward the southwest are the only reliable indicators of the passage of the ice stream in this "buried" section of its extent. While the east-southeast striations indicate that the advancing ice stream preceded the late Cochrane 220º flow, the mapping of several thousand iceberg furrows in Quebec and Ontario, directed toward the east and overprinted on Cochrane flutes, indicates that the ice stream also outlasted the Cochrane episode. It calved in Lake Ojibway from a position to the northwest of Hearst, Ontario until final drainage as indicated by ice-rafted debris found at the surface and in the upper part of cores from sub bottom lake sediment. The removal of large volumes of ice in the marginal part of the retreating ice sheet by the eastward progression of the ice stream accelerated deglaciation, and eventually triggered the Cochrane surges. The encroachment of the ice stream in Lake Ojibway is correlated with varve 1528 of Antevs¿ series (500 to 600 years before final lake drainage) shortly before the onset of the Cochrane surges. With this southern component the Winisk ice stream becomes the largest terrestrial ice stream in the Hudson Bay basin. These new results clarify the sequence of events associated with the chronology of Cochrane surges.
Summary(Plain Language Summary, not published)
This is a paper presented on a relict ice stream preserved in northern Ontario, prior to deglaciation of the Laurentide Ice Sheet. The timing of this ice surge is important in terms of how the Hudson Ice Centre in northern Quebec was later affected by other ice streams in Ungava and eastern Labrador coastline. This research is an output of legacy data by the first author, combined with new data from the GEM2 Hudson-Ungava Project, Core Zone Surficial Activity. Ultimately such research will have a positive impact for mineral exploration in northern Canada.