CGRG Bibliography of Canadian Geomorphology
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Author : Dube-Loubert, H.; Roy, M.; Veillette, J.; Parent, M.; and Lamothe, M.
Date : 2007.
Title : Ice flow directions and transport in glacial sequences of the James Bay lowlands of Québec: implications for mineral exploration in areas of thick drift cover.
Publication : CANQUA Ottawa 2007. Canadian Quaternary Association Conference, June 4-8, 2007. Carleton University, Ottawa, Ontario, Canada.
Issue :
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Abstract
Glaciated regions bearing thick glacial sedimentary cover present a considerable challenge to mineral exploration. To achieve success in such regions, mining companies using glacial deposits in order to locate diamond, gold, or base metals source areas must have access to data on glacial transport and ice flow directions associated with the glacial deposits obscuring the sub-surface bedrock geology. This is particularly the case in the James Bay lowlands of Québec, where little information is available on the composition and provenance of glacial deposits forming the extensive glacial sequences of this region. The glacial geology of this area is also complicated by the fact that this region lies near the former geographic center of the Laurentide ice sheet, and was thus subject to different ice advances coming from the near-by ice-dispersal centers. Because success in drift prospecting is highly dependant on accurate knowledge of ice flow patterns and glacial transport, it is important to increase our understanding of the lowlands’ stratigraphy. Here we report till sedimentological and compositional (petrology, mineralogy, geochemistry) data from stratigraphic sections exposed along the Harricana River, in the lowlands of Québec. Our investigations indicate that the regional stratigraphy consists of at least 3 to 4 distinct till units that are separated by a 20-m thick unit of varves. This till sequence lies on a nonglacial unit consisting of fluvial sands bearing wood-fragments and showing a normal drainage towards the bay. Till fabrics and the petrological data indicate that the till units record a complex succession of ice advances from the center of the ice sheet as well as different advances from the Labrador-Québec sector. Geochemical and sedimentological analyses are currently being processed, and the results should provide additional constraints on the sequences of events recorded by the glacial deposits. The provenance of tills should also be reinforced by the application of radiogenic tracers (Sm-Nd, Ar isotopes) on the glacial deposits. The nonglacial unit is being dated by both radiocarbon and Optical Luminescence methods. The combined compositional and chronological data will characterize the provenance of tills and provide an age constraints on the sequence of shifting ice flows. These results will integrated into a detailed chrono-stratigraphic framework that will contribute to effort in mineral exploration in region affected by thick-drift cover, and will also be useful to the interpretation of stratigraphic data coming exclusively from overburden drilling.
Bibliography of Canadian Geomorphology