The area is underlain by regionally metamorphosed Paleozoic sedimentary and volcanic rocks which consist largely of gneisses with augen-shaped porphyroblasts of feldspar and large amounts of quartz occurring as veins, lenses and irregular patches throughout the gneiss. As well, coarse grained amphibolite and garnet-bearing quartz-biotite schists occur with several lenses of coarsely crystalline limestone, locally with tremolite. South of the Polaris Taku Mine (104K 003) the phyllitic sediments have a very high silica content and the presence of limestone suggests a correlation with the Permo-Pennsylvanian chert-limestone succession.

These rock are overlain by the Upper Triassic Stuhini Group volcanics. Mineralization at the Polaris Taku Mine is associated with the base of the Stuhini Group volcanics which consists of altered greenstones that have undergone intense chlorite and carbonate alteration.

In 1948, a hole was drilled westwards at minus 40 degrees for 122 metres on the Martha claim, to explore under the valley slope. The core consisted of schistose, chloritic greenstone crosscut by innumerable white quartz and carbonate veinlets with grey, pyritized altered rock. The grey, altered rock was intersected from 45 to 99 metres. It was reported by the owners that some sections from this core contained mineralization of economic importance. The assay results and mineralogy were not published.