The Packrat occurrence is located about 30 kilometres northeast of Kimberly and about 1 kilometre south of Wolf Creek.
The Packrat area is underlain by rocks of the Helikian Aldridge Formation (Purcell Supergroup) and the Fort Steele Formation (Purcell Supergroup) intruded by gabbro and diorite of the Mesoproterozoic Moyie Intrusions.
The Packrat occurrence is associated with the "Packrat shear", a high angle ductile shear hosted within a gabbro body approximately 1 kilometre south of Wolf Creek. The shear is exposed in a series of old prospect pits and workings for a strike length greater than 300 meters and appears to have a maximum width of over 3 metres in one working. Wallrock alteration is developed proximal to the shear up to 3 to 4 meters away and includes a zone of weak bleaching followed by a zone of sericite, iron carbonate, goethite, hematite, and rare chalcopyrite that is cored by a pervasive sericite alteration of the host rock, pyrite flooding and quartz-sulphide and quartz-carbonate-calcite-pyrite veins and stockworks. Quartz-calcite stringers with pyrite and chalcopyrite hosted in fractured gabbro may be a distal alteration halo to the shear. Samples of quartz-sulphide veins ran up to 13.5 grams per tonne gold (Assessment Report 33700).
Quartz blowouts along the shear have been exposed in an old pit where a bull quartz vein over three meters wide is developed. Selective sampling of more sulphide and oxide rich material from the blowout returned up to 1.8 grams per tonne gold (Assessment Report 33700). The Packrat Shear appears to terminate to the north at an east-west striking, north dipping argillic fault. The east-west fault is strongly clay-altered with chloritic gashes and thin goethite-rich quartz veinlets. One composite sample (SKPX12-31) from this zone over a one-meter width assayed 22.03 grams per tonne gold (Assessment Report 33700).
The Packrat shear is hosted within a gabbro body that appears to be a flat lying dike. Sediments exposed to the west are northwest striking and moderate to steeply east dipping and are clearly cut by the gabbro which appears to pinch out in a zone of mylonitic shearing.
East of the Packrat shear the topography is quite subdued and it appears that the gabbro is laying flat in this area with Aldridge Formation (unit A1c) graphitic mudstone shallowly underlying it. Further east a section of laminated greyish to buff siltstone (possibly Aldridge Formation (unit A1c 2)) with disseminated euhedral pyrite is exposed. On the south slopes above Wolf Creek, northwest striking, and moderately dipping sediments are exposed with unit A1c 1 in fault contact with Fort Steele Formation quartzites. A series of old pits are located along the fault where quartz-sulphide veins and stockworks host copper and lead mineralization.
Refer to the Wolf Creek (082GNW136), Jacleg (082GNW135), and the Lazy 19 (082GNW059) showings for related geological and work history details.
