|Summer, British Columbia
The Summer property is located northeast of Cranbrook and comprises 1,782 ha (4,403 acres), located east of Summer Lake at the confluence of Galbraith and Summer creeks. The property covers a silica-deficient, potassium-enriched ultramafic occurrence having xenolithic textures (including sedimentary, lower crustal and possibly mantle inclusions) in a carbonatized and/or serpentinized igneous matrix. Furthermore, they contain a minor component of mantle and/or crustal inclusions and foreign xenoliths.
Previously reported geochemical results of samples taken from the SUMMER occurrence have confirmed an ultramafic affinity. Furthermore, ultramafic nodules of mantle origin and kimberlitic indicator minerals have been reported and, in the case of clinopyroxenes, confirmed at the nearby BLACKFOOT occurrence. At present, it is not clear where these intrusives originated relative to the diamond stability field. It is particularly significant that diamond-bearing lamproites north of Golden restore palinspastically outboard of the SUMMER occurrence. Furthermore, the one widely accepted kimberlite in the Rocky Mountains (and additional diamond-bearing kimberlites of the ICE property) restores to the east. Finally, K.L. Currie of the Geological Survey of Canada regards the diamond potential of the Rocky Mountains alkaline province as good for the following reasons:
(i) “The alkaline rocks clearly came up through continental crust,
(ii) The alkaline (rocks) have diverse compositions and ages. Both these conditions are necessary, but not sufficient.
Likewise, it is not sufficient to demonstrate “kimberlitic” chemistry, unless the appropriate xenocrysts are present (chrome diopside, pyrope, magnesian ilmenite) ... it has not been demonstrated that any Cordilleran kimberlite or Iamproite-like rocks have passed through the diamond stability field. It seems to me that the appropriate P-T determination (from indicator minerals or thermobarometry) is essential” ... (K.L. Currie, pers. comm. 1993).
The Rocky Mountains in this area are underlain by Archean basement for which an age of 3.2 billion years has been determined, consistent with age of peridotitic diamonds determined world-wide (3.3 billion years - Levinson et al. 1992, Kirkley et al. 1992). Zircons recovered from several diatremes in the Rocky Mountains have been determined to have Archean ages. A partial suite of indicator minerals has been recovered for which clinopyroxenes have compositions comparable to diamond inclusion clinopyroxenes from kimberlites around the world. Most important of all, the most reliable diamond indicator mineral, diamonds, have been recovered from pipes which were both inboard and outboard of the SUMMER diatreme.
Furthermore, gem quality and near gem quality macro-diamonds have been documented by Consolidated Ramrod Gold Corporation from the ICE property (subsequently optioned by Skeena Resources Ltd), only 20 kilometres to the east.
Jasper Mining Corporation, trading symbol: JSP
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