The region in which the Mor showing is located is underlain by the Jurassic to Tertiary Coast Plutonic Complex, near its eastern margin where Tertiary felsic intrusive rocks dominate over older intrusions. A number of porphyry-type occurrences have been located in this part of the Coast Plutonic Complex and the Mor showing is probably such a occurrence.

The showing occurs in an area of Eocene quartz diorite and granodiorite which has intruded an older Cretaceous stock. Late aplite dykes cut all other rock types. Sulphide mineralization consists of covellite, chalcopyrite and pyrite as blebs, smears and disseminations in quartz veins and granodiorite. Although the granodiorite in places contains primary biotite, secondary biotite, recognized by its felted texture, has been described in rocks containing sulphide mineralization.