Geology and Mineral Occurrences of the Goldstream River Area
(NTS 82M/9 and part of 10)

BCMEMPR Open File 1995-02

by M. Colpron, J.M. Logan, G. Gibson and C.J. Wild
Digital compilation in 1995 by P.J. Desjardins

Revision and Cartography in 2008 by J.M. Logan and C.-Y.M. Lin

View Open File Color Map, Updated 2008 (PDF, 8.7 MB)

View Open File Black and White Map (PDF, 3.1 MB)

Open File 1995-02 discusses the geology and mineral occurrences of the Goldstream River area (82M/9 and part of 10) in the northern Selkirk Mountains in eastern British Columbia. The Open File map presents geology at 1:50 000 scale, and has a legend, several geologic cross sections, and a table of mineral occurrences. More detailed geology of the Goldstream mine area is presented in Open File 1995-03. In 2008, Open File 1995-02 was updated with geology, geochemistry and addition of color.

The geology and structure are complex. The oldest exposed rocks correlate with the Neoproterozoic Horsethief Creek Group. One unit consists of fine quartz grit, impure quartzite and pelitic schist calc-silicate layers. Others consist of coarse amphibolite, grey marble, feldspathic grit and phyllite, rhythmically laminated phyllite and siltstone, calcareous phyllite and fine grit, micaceous quartzite, greenstone, dolostone, and black calcareous phyllite and dark grey marble. Units with pelitic schist, quartzite, garnet amphibolite, and gneiss may be Paleozoic. Eocambrian Hamill Group comprises five units. The lowest consists of phyllite and quartzite. Above are massive and cross-bedded quartzite with micaceous quartzite, grit and phyllite layers; dolomitic marble; rhythmically laminate sandstone and siltstone; and massive to amygdaloidal greenstone, mafic schist, volcanic conglomerate, grit and tuff. The Lower Cambrian Badshot Formation is dolomitic marble. The Index Formation of the Cambrian (?) to Devonian (?) Lardeau Group is divided into six units generally and undivided locally. From lowest to highest, the units consist of marble and black limestone, graphitic phyllite and schist with calcareous phyllite and marble, micaceous quartzite and siliceous phyllite, chlorite schist and greenstone, marble, quartz grit with laminated micaceous quartzite, calcareous grit, schist and dolomitic layers.

The Middle Jurassic Adamant pluton consists of hypersthene-augite monzonite and hornblende granodiorite. The Early Cretaceous Goldstream pluton contains quartz monzodiorite and biotite granite with local megacrystic granite and aplite dikes. The Cretaceous (?) Long Creek stock is locally megacrystic biotite granite, and the Late Cretaceous (?) Downie stock consists of leucogranite that is locally garnet bearing.

Rocks in the area have been multiply deformed into a series of thrust slides that dip easterly and host upright to overturned to west verging isoclinal folds. The map sheet is bounded on the west by the Columbia River fault, which dips moderately toward the east and shows normal movement. Rocks west of this fault comprise the Monashee complex.

Mineral occurrences include: copper-zinc-silver-gold-bearing Besshi-type volcanogenic massive sulphide deposits, like the formerly producing Goldstream mine; stratabound carbonate replacement deposits with lead, zinc, silver and gold values; zinc-copper-silver skarns; base metal veins with or without tungsten and gold; placer gold; and industrial mineral potential, particularly for garnet.