The Gran occurrence is located 15.5 kilometres west of the confluence of the Gataga and South Gataga rivers in the Muskwa Ranges of the Northern Rocky Mountains (Assessment Report 6689, Figure 10).

The occurrence is in a belt of Proterozoic through Mississippian basinal-facies sedimentary strata known as the Kechika Trough, part of Ancestral North America (Exploration and Mining Geology, Volume 1, page 1; Geological Survey of Canada Map 1713A). Structurally, the region is deformed into a series of northwest-trending folds and imbricate thrust faults.

The Gran claim is underlain by rocks of the Cambrian Atan Group and the overlying Cambro-Ordovician Kechika Group (Assessment Report 6689; Geological Survey of Canada Memoir 373, Map 1343A). In this area, the lower part of the Atan Group consists of medium- to coarse-grained quartz sandstone, and the upper part comprises massive grey limestone (archeocyathid-bearing, north of the claim) and limestone breccia. These lithologies change abruptly at the Kechika Group contact, replaced by interbedded silty, dolomitic slate; black, non-calcareous and locally pyritic slate; and minor argillaceous limestone. The Kechika Group rocks form the core of a tight, northeast-overturned syncline, flanked by the Atan Group. Strata generally strike about 320 degrees and dip 70 degrees southwest.

The occurrence is centred on the main showing of mineralization, in the north-centre of the claim. Dark-grey slate with numerous calcite and quartz veinlets, near the base of the Kechika Group, contains sphalerite in narrow zones on bedding planes. The sphalerite crystals are 1 to 5 millimetres across and may be altered to smithsonite. The zone is 10 to 30 centimetres wide and extends along strike for approximately 70 metres.

In 1977, a sample (7R12R) from the zone assayed 0.58 per cent zinc, whereas a rock sample (7K1R) from a similar minor zone located approximately 700 metres to the southeast assayed 11.45 per cent zinc (Assessment Report 6689).

Other minor zones of zinc mineralization are reported approximately 1 kilometre to the southwest, and a minor zone of limestone with bleached sections hosting native copper and malachite are reported approximately 800 metres to the west-southwest of the ‘main’ zone.

Work History

In 1977, Granby completed a program of geological mapping and geochemical (rock, silt and soil) sampling on the area as the Gran and X properties.