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Proactive disclosure Print version   | |  Kimberlite Indicator Minerals in Till, Central Slave Province, Northwest Territories
Slave NATMAP project encompasses an area of active diamond exploration. During regional surficial mapping, 300 till samples of 10-kg weight were collected (one sample per 180 km2 ) and analyzed for kimberlite indicator minerals n order to establish regional background mineral concentrations, and to indicate areas that may warrant further exploration. The maps displayed show distributions of pyrope, chrome diopside, chromite and Mg-ilmenite indicators in the medium-sized (0.25-0.50 mm) sand fraction of the till. Striations indicate that glaciers have transported material southwest, west, and northwest of kimberlite sources. A major glacial dispersal train trends northwestward for more than 100 km from the Lac de Gras kimberlite cluster, but smaller dispersal trains and isolated indicators suggest that kimberlite sources are present at several other locations. The data indicate that indicators are more abundant in the 0.25-0.5 mm size fraction than in coarser sizes, and that pyrope is typically the most abundant indicator, although some locales with no pyropes have been identified as potential kimberlite sources. Kelyphite reaction rims are present on some pyrope grains transported up to 35 km from source pipes: the presence of kelyphite does not necessarily imply proximity to a kimberlite source.
Recommended Citation L.A. Dredge, D.E. Kerr, L.M. Kjarsgaard, R.D. Knight, and B.C. Ward 1997: Kimberlite indicator minerals in till, central Slave Province, Northwest Territories. Geological Survey of Canada, Open File 3426. Copies of this Open File may be obtained from: Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario. K1A 0E8 Author: Daniel Kerr
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