The Mario South occurrence is located west of an unnamed north flowing tributary of the Adam River, approximately 750 metres south of the Adam River.

The area is underlain by Upper Triassic Vancouver Group rocks comprised of a thick sequence of tholeiitic basalts with minor intercalated sediments of the Karmutsen Formation. The Vancouver Group rocks are in fault contact with the underlying Permian Sicker Group sediments. Granodiorite of the Jurassic Island Plutonic Suite, intrudes the older rocks.

The occurrence is underlain by Karmutsen volcanic rocks which are crosscut by a few east striking quartz feldspar porphyry and feldspar porphyry dikes, presumed to be related to the Island Plutonic Suite. Several north west and east striking faults cut the rocks in the central claim area.

Locally, a flat laying quartz vein in volcanic rocks hosts pyrrhotite, chalcopyrite and minor molybdenite mineralization. In 1985, drilling encountered five small veinlets dipping 8 degrees (Assessment Report 13589).

In 1985, Canamin Resources completed a program of prospecting, soil sampling and a single diamond drill hole, totalling 8 metres.