The Tred occurrence consists of copper mineralization in mountainous terrain southeast of the Tredcroft Glacier, 7 kilometres northwest of the head of Franklyn Arm of Chilko Lake. It was discovered during a mineral resource assessment project in the Chilko Lake area (Bulletin 81).
The occurrence lies within granodioritic stock of the Late Cretaceous to Paleocene Bendor suite about 3 kilometres southwest of an important northwest-striking fault, the Stikelan fault (Geological Survey of Canada Open File 1163). The stock was emplaced into a complex belt of Upper Triassic and Lower Cretaceous sedimentary and volcanic rocks, between the Stikelan fault and the Jurassic to Tertiary Coast Plutonic Complex several kilometres to the southwest. The immediate country rocks are dominantly Upper Triassic andesitic volcanics and minor sedimentary rocks of the Mount Moore Formation. The rocks strike northwest and dip moderately southwest. The stratigraphy is untruded by a stock of the Late Cretaceous to Paleocene Bendor Suite. The stock is about 4 kilometres long and about 2 kilometres wide, elongate in a northwest direction, in common with the dominant structural trends in the area. The eastern side of the intrusion is cut by several northwest-striking faults, accompanied by limonitic alteration. The Bendor intrusions consists of biotite-hornblende granodiorite, quartz diorite, tonalite and diorite.
The Tred showing occurs on the south side of the stock and consists of disseminated, unspecified copper mineralization (Bulletin 81). Alteration of the quartz diorite and adjacent volcanics is minimal, with only minor chloritic and sericitic alteration present, and a few quartz-epidote veins. Talus of a slightly more mafic diorite is presumed to be derived from the southern margin of the stock (Bulletin 81). It contains disseminated pyrite, chalcocite and tetrahedrite. Two rock samples yielded anomalously high values of silver, copper, lead, zinc and molybdenum (Bulletin 81).
The Tred showing is probably similar to copper mineralization present 2.5 kilometres away at the northwest end of the stock, covered by the Rum 66 occurrence (092N 008) (Assessment Report 2671). Refer to Rum 66 for related geoloigcal information and work history details.
