The geology underlying the Dolly Varden property consists of volcano-sedimentary rocks belonging mostly to the lower and middle Jurassic Hazelton Group. These include intermediate volcanic and volcaniclastic rocks of the Betty Creek Formation and bimodal volcanic and sedimentary rocks of the Salmon River Formation.
The principal silver-base metal deposits of the Kitsault River valley have been interpreted as vein mineralization by early workers. Devlin (1986) reinterpreted the main deposits to be volcanic exhalative in origin. Deposits of this type are formed as sub-aqueous hot-spring type deposits on the seafloor, as products of hydrothermal solutions that have vented from sub-seafloor fracture and fault systems. Furthermore, the silver deposits of the upper Kitsault valley are mapped with important geological similarities to the Eskay Creek deposit, providing an analog for exploration on the Property.
The most prominent mineralized zone on the Property is an aerially extensive horizon of chemical sediment (“exhalative”) mineralization, known as the Dolly Varden-Torbrit Horizon (the “DVTH”) that extends from the Dolly Varden mine, on the west, passing though the North Star underground workings and continuing into the Torbrit mine, on the east. The DVTH exhalative body forms an almost continuous sheet, ranging in true thickness from 3 to 38 m, which extends from the Dolly Varden West zone to Moose-Lamb. Syn-depositional as well as post-dispositional faults have created a number of basins that divide the DVTH into offset blocks.
Separate from the DVTH body, the Red Point zone (on the western fringe of the upper Kitsault Valley) and the Wolf (on the eastern side of the valley) each have geological similarities to the targeted hydrothermal vein and sub-aqueous hot spring geology but are interpreted to share a position higher in the volcanic stratigraphy than the DVT horizon.