Lithologies present in the CS occurrence area comprise volcanic and lesser sedimentary rocks of the Lower to Middle Jurassic Hazelton Group, Lower to Upper Cretaceous Kasalka Group, Lower Cretaceous Skeena Group and Middle Jurassic to Lower Cretaceous Bowser Lake Group. Tuffs of the Lower Jurassic Telkwa Formation (Hazelton Group) are the most common rock type, varying from finely laminated to coarse agglomerates.
Stratigraphic units are intruded by two Late Cretaceous quartz dioritic stocks of the Bulkley and Kasalka intrusions. Exposed porphyry-type alteration and mineralization is associated with the Kasalka intrusion. Thermal alteration of sedimentary rocks occurs at the contact of the Kasalka intrusion, but elsewhere stratigraphic rocks exhibit a regional epidote-carbonate-chlorite-quartz assemblage.
Drilling in the intrusive rocks intersected chalcopyrite, molybdenite, pyrite, magnetite and hematite occurring as disseminations and in veinlets. Traces of sphalerite have also been noted. The hostrocks are well fractured and exhibit concentric zones of hydrothermal alteration.
