Bulletin 063

Bulletin 063

BUL 063

The Diamond Potential of Alberta

This study by the Alberta Geological Survey which was funded by the Canada-Alberta Partnership on Minerals, was undertaken in response to the discovery of diamonds in kimberlitic diatribes in the Lac de Gras area of the Northwest Territories and the Fort a la Come area of Saskatchewan. These discoveries indicate that potential exists for the discovery of diamondiferous diatremes in other areas of Canada, such as Alberta.

The primary objectives of this study were to identify geological anomalies and target areas for diamond exploration, and to provide selected geological, geophysical and geochemical data that would assist industry in its exploration for diamonds in Alberta.

Alberta is favourable for diamondiferous deposits because: the Province is underlain by large areas of thick Precambrian crust that acted as 'cool roots'; Alberta contains major faults, arches, grabens and other tectonic features that may have provided conduits for the intrusion of diamond-bearing kimberlitic or lamproitic diatremes; there is evidence of at least four, and possibly five ages of volcanic activity in Alberta, including mid-Cretaceous to Late Cretaceous, which was the most prolific period for diamondiferous kimberlitic volcanism in the world; numerous bentonites and tuffs exist in the Phanerozoic succession in Alberta, and in several places the bentonitic horizons are anomalously thick (up to 11.6 m) and may have resulted from local volcanic venting; and there are a large number of geological, geophysical and geochemical anomalies in Alberta that may have been, or are related, to the emplacement of potentially diamondiferous kimberlitic or lamproitic diatremes.

To date, diamond exploration by industry also indicates that Alberta has potential to host diamondiferous kimberlite or lamproite deposits. The first kimberlitic intrusion reported in Alberta has been discovered in the Wapiti Group near Grande Prairie. Diamonds have been discovered in surficial sediments west of Edmonton at locations near Evansburg and Hinton, in southern Alberta in the Sweetgrass Hills area, and in Cretaceous-Tertiary sediments southeast of Red Deer. There are numerous diamond indicator mineral anomalies in Alberta, with some indicator grains having excellent chemistry indicative of possible local diamondiferous kimberlitic or lamproitic diatremes.Although Alberta has the potential to contain diamondiferous diatremes, the province has barely been explored for such deposits. Extensive drift, poor bedrock exposure and reworking of diamond indicator minerals in multiple cycles has hindered exploration across much of Alberta. Further geoscientific work is required to delineate areas of high potential and to further stimulate industry exploration activities.

Dufresne, M.B., Eccles, D.R., McKinstry, B., Schmitt, D.R., Fenton, M.M., Pawlowicz, J.G. and Edwards, W.A.D. (1996): The diamond potential of Alberta; Alberta Energy, AE/AGS Bulletin 63, 164 p.