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TitlePalimpsest glacial dispersal trains and implications for mineral exploration
AuthorPlouffe, A; McMartin, I; Veillette, J J
SourceGeological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Programs with Abstracts vol. 34, 2011, 1 pages; 1 CD-ROM
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20110028
Meeting2011 GAC-MAC-SEG-SGA Joint Annual Meeting; Ottawa; CA; May 25-27, 2011
Mediapaper; CD-ROM; digital
File formatpdf
Subjectssurficial geology/geomorphology; economic geology; ice movement directions; ice transport directions; dispersal patterns; sediment dispersal; glacial landforms; glacial deposits; tills; mineral occurrences; mineral potential
ProgramMountain Pine Beetle, Geoscience for Mountain Pine Beetle Response
AbstractA glacial palimpsest dispersal trains is defined as a pre-existing train deposited in a given sense of ice movement that has escaped destruction or been modified by subsequent ice movement(s) of different direction(s). Such dispersal trains have been identified in glaciated regions of the Keewatin and Labrador Sectors of the Laurentide Ice Sheet, in the Appalachian Ice Complex, and the Cordilleran Ice Sheet. More are being discovered as complex ice-flow histories are deciphered through detailed and regional studies. The palimpsest dispersal patterns are defined by till components such as clasts, mineral grains, or geochemical concentrations of elements or compounds of known provenance. In some cases, the first dispersal train is only partly modified by a subsequent ice movement which implies that the till associated with the first ice movement was not completely eroded and redeposited or buried by the younger ice movement(s). A parallel can be made between palimpsest glacial dispersal trains and palimpsest glacial landforms in which case an earlier formed set of glacial landforms is partly reworked, deformed or overprinted by a subsequent ice movement. Palimpsest dispersal trains and landforms attest to the complexity of the erosional and depositional environment at the base of glaciers which is influenced by parameters such as topography, sediment load, substrate composition, ice physical conditions (e.g. temperature, velocity), and duration of ice-flow events. Correct interpretation and recognition of palimpsest dispersal trains must rely on a complete understanding of the ice-flow history which can be achieved by interpreting ice-flow indicators present at all scales from micro-features on bedrock outcrops to landforms interpreted from digital elevation models. Implications for mineral exploration activities using drift prospecting techniques, must take into account the complete ice-flow history of a region because glacial dispersal patterns detected will be the net result of all ice movements.