Kimberlite indicator mineral and geochemical reconnaissance of Southern Alberta

An indicator mineral and geochemical survey designed to examine diamond and metallic mineral potential, glacial sediment transport history, and both exploration and environmental geochemistry, was carried out in southern Alberta in 1992. Sampling sites were randomly selected prior to field work, with two sites in 40 × 40 km cells designated for the sampling of till (unsorted glacial sediments) and soil, and additional sites designed to define local variability of soils. At 252 sites, a 25 ℓ sample of till was collected from 1 to 2 m depth from surface exposures, mainly road cuts. Soil samples from the A and C horizons were obtained from 352 sites randomly distributed on all parent materials. Processing of the till samples, followed by mineralogical and chemical analysis, resulted in the confirmation of an average of one indicator mineral per two samples. Several areas where favourable kimberlite indicator mineral results are clustered were defined. Additional lithological, mineralogical, and geochemical analyses of till were used to provide evidence of the bedrock source of the sediment. Sediment consisting of material transported generally southwestward by Pleistocene glaciation radiating from the Canadian Shield can be distinguished from Pleistocene sediments north and south of Calgary which contain abundant material glacially transported from the Cordillera. The soil geochemical data are of less direct application to mineral exploration than the till data, owing to variable texture and greater modification by pedological processes, but these data provide useful information of relevance to environmental and agricultural issues.