The Sob showing is hosted by rocks of the Lower Jurassic, Unuk River Formation, Hazelton Group. The rocks include argillite and greywacke, some of which have been hornfelsed. These sediments are black, well foliated and may be relatively siliceous and massive or fissile and slaty. A series of andesitic to dacitic dyke swarms intrude these sediments particularily at the 900-1100 metre elevation level.

Several quartz-calcite veins occur in the vicinity of the dykes. The veins are up to 20 centimetres thick, host minor pyrite and are oriented conformable and oblique to bedding. A carbonate alteration zone extends 2-10 metres out from the veins. This zone is siliceous and contains finely disseminated pyrite and copper staining.

One sample from the carbonate alteration zone assayed 0.07 grams per tonne gold, 0.34 grams per tonne silver, 0.01 per cent lead and 0.004 per cent copper (Assessment Report 9234).