The area is underlain by several phases of the Upper Cretaceous- Tertiary Coast Plutonic Complex consisting of gabbro, hornblende- biotite diorite, biotite granodiorite, soda granite, and muscovite granite. A roof pendant of Hazelton volcanics occurs to the northwest. Northwest trending dykes ranging in composition from diorite to quartz monzonite cut all rocks.
Pyrite, molybdenite, and chalcopyrite occur in narrow quartz veinlets and to a lesser extent as fracture coatings and as disseminations. In Gossan Creek, three weakly mineralized stockworks, 15 to 50 metres wide, occur over a 750 metre length and a 450 metre vertical distance, within a 1050 by 450 metre east trending plug of quartz-feldspar porphyry. Chip sampling of the mineralized zones gave weighted averages of 0.019 per cent molybdenite and 0.029 per cent copper over three metres. The best interval overall is 50 metres of 0.03 per cent molybdenite (Assessment Report 14011). Silicification, feldspathization, and sericitization are structurally controlled and associated with molybdenum mineralization.