The following description is modified slightly from Assessment Report 21318: "Mama Susu-D, E and F shwoings (104B 373, 374, 375) are all located in a small valley containing an outflow stream fed by an icefield, and are separated from each other by varying widths of less intensely altered (sericite-calcite-chlorite-limonite) andesitic pyroclastics and siltstones. They consist of shear zones 30, 20 and 50 metres wide separated by 70 and 100 metres respectively, all striking northeast-southwest. All are very strongly to completely altered to sericite with auxiliary quartz and disseminated pyrite (up to 5 per cent). Locally they contain poickets of massive sulphide with galena (up to 30 per cent), pyrite (up to 50 per cent), limonite (up to 50 per cent), sphalerite (up to 10 per cent) and minor stibnite, wad and malachite-azurite staining.

Gold and silver assays of grab samples from Mama Susu-D were generally low, with a high of 0.010 ounce per ton gold in sample #34556 and 12.9 ounce per ton silver in sample #34523. Base metals ranged from 0.01 per cent to 0.73 per cent copper, 0.04 per cent to 2.86 per cent lead, and 0.07 per cent to 3.73 per cent zinc. All the highest base metal assays were derived from sample #34523 which consisted of strongly sericitized andesitic tuffs with 1 to 2 per cent galena, limonite and wad. All of the above samples were collected from subcrop."

According to Open File 1991-21 this showing occurs in the Betty Creek Formation of the Lower Jurassic Hazelton Group. Fossils found approximately 500 metres south of the showing, in rocks that appear to be correlative with those that host the showing, indicate Hettangian to Sinemurian (or Pliensbachian) ages.