The Crazy Creek showing is within what has been termed the Pioneer Ultramafite (Wright, 1974), an alpine-type peridotite body which is enclosed in lower greenschist facies, sediments, and volcanics of the Mississippian to Jurassic Bridge River Complex (Group). The ultramafite is linked to the President Ultramafics, which in turn are probably correlative with the Permian and older Shulaps Ultramafic Complex. Talc-carbonate alteration occurs along fault zones within the ultramafite which is highly serpentinized.

A talc-magnesite-chlorite zone, ranging from a few metres to a few tens of metres wide, is developed near a fault and grades into serpentine north of "Peak 1". The rock is strongly sheared and foliated, and consists of chlorite patches (replacing orthopyroxene) veined by calcite and dolomite in an extremely fine-grained matrix (0.01 millimetre) of talc-chlorite.

A talc-carbonate schist of variable width is developed between serpentine and the contact with country rock. The talc zone is marked by either an abrupt shear zone or a gradational contact. There is a gradual increase of talc and talc/carbonate schist which contains 45 per cent magnesite in a matrix of fine-grained talc and minor chlorite.