The Tudyah Lake showing lies in the Rocky Mountain Trench at the western margin of the Ancestral North American miogeocline, approximately 25 kilometres south of the town of Mackenzie. This area is underlain by Cambro-Proterozoic Misinchinka Group quartzite, siltstone and slate and Lower Cambrian Gog Group limestone, dolostone, quartzite, siltstone and slate. Regional subgreenschist facies metamorphism extends west to the McLeod Lake fault, west of which metasedimentary rocks attain migmatitic sillimanite grade.

A small showing of grey gritty quartzite "only sparsely mineralized with pyrite" was reported to contain 137 to 206 grams per tonne gold but there is no evidence to support this. In 1959, two pyritic samples collected by S. Holland of the Ministry of Mines assayed nil in gold. No recent work is known to have been performed on the showing.