The region in which the Tetachuck Lake showing occurs is within the Intermontane Belt, underlain dominantly by Lower to Middle Jurassic volcanic and sedimentary rocks of the Hazelton Group. These assemblages are overlain by the Upper Cretaceous to Lower Tertiary Ootsa Lake Group and Miocene plateau basalt. Intruding Lower Jurassic rocks of the Hazelton Group in the northeastern part of the map sheet is a belt of granodiorite, diorite and quartz diorite plutons of the Lower Jurassic Topley intrusive suite. Felsic plutons of probable Cretaceous age intrude both Lower and Middle Jurassic Hazelton strata.

This showing comprises a small (5 to 10 centimetres wide) sphalerite-calcite vein within Lower Jurassic Hazelton Group argillite. A selected sample in 1963 assayed 26.80 per cent zinc, 5.142 grams per tonne silver and 0.1714 grams per tonne gold (Geological Survey of Canada Memoir 324, page 53). In the area around Tetachuck Lake several pyritized zones were noted. Some are reported to carry low gold values.