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Geology and mineralogy of the Strangward Copper Property, South Tetsa River, B.C.

University of British Columbia

The Strangward Copper Property lies in the front range of the Rocky Mountains, northeastern British Columbia, near the headwaters of the South Tetsa River. It is readily accessible from the Alaska Highway (mile 392) at Summit Lake, B.C. by a pack trail approximately 20 miles in length. Sedimentary rocks exposed on the property consist of dense, fine grained lime stones , and siliceous limestones, and calcareous and carbonaceous sandstones, and thick bedded and massive white feldspathic quartzites. They have been gently folded into anticlines and synclines with northwesterly trending axes. (Rocks of claim group "C" in the foothills are closely folded black shales). There are many vertical faults, some occupied by diabase dykes from 30 to 125 feet in width. The general trend of the faulting is northwesterly. The main ore controls are as follows; (1) Most well defined faults are occupied in places by quartz-carbonate veins which are erratically and sparsely mineralized. In general, faults provided access for mineralizing solutions; hence are considered a primary control in the formation of mineral deposits. (2) Carbonaceous sandstone, as indicated by the locations of four showings, seemed to be most favorable for the deposition of copper minerals within the veins although replacement of the rock was not observed. (3) Fractures, up to 1 inch in width and a few inches in length, filled by copper minerals were observed in brittle white feldspathic quartzite. It is believed that thick beds of quartzite, cut by one or more sets of faults, constitute a structurally favorable host rock. (4) Pyrite replacement deposits, the largest 10 feet in width and 50 feet or more in length, were seen in many places within altered diabase dykes. Although only traces of copper minerals have been found, the existence within these dykes of large, low grade copper replacement deposits is a possibility. (5) Sparse copper mineralization was observed in several places within the altered limestone adjacent to two large dykes. There is a possibility of replacement deposits within this zone of alteration (perhaps 15 or 20 feet in width). (6) Mineralization has not been found in the unaltered upper limestone. This formation however, cannot be regarded as an unfavorable host rock for replacement or vein deposits by the limited amount of work done during the 1950 field season. Study of a dozen polished sections shows two primary copper sulphides, chalcopyrite and bornite, to be present, with chalcopyrite the more abundant of the two. Chalcocite is abundant in some sections but is apparently supergene. However, some primary chalcocite occurs as ex-solution intergrowths with bornite. Secondary covellite is also abundant. Hydrous iron oxides and malachite form the bulk of some sections.

Text

2012-02-28

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http://hdl.handle.net/2429/40989

Geological Sciences

University of British Columbia

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