UBC Theses and Dissertations
Geology of the Alice Arm Molybdenum Prospect : Skeena Mining District, Alice Arm, British Columbia Drummond, Arthur Darryl
The composite Lime Creek stock outcrops on the Alice Molybdenum Prospect, six miles southeast of Alice Arm on the northern coast of British Columbia. An aureole of biotite hornfels was developed in the surrounding Jurassic Hazelton group by the intrusion. Within the composite stock, intrusive relationships suggest the following sequence: Lime Creek granodiorite, Lime Creek quartz diorite, East quartz diorite, alaskite, granodiorite porphyry and its related breccia. Phenocrysts in the granodiorite porphyry are resorbed quartz, zoned potash feldspar and zoned plagioclase. Reverse followed by normal zoning is present in the feldspar phenocrysts. A history of water vapor pressure fluctuations from initially high to low and then to high again is suggested by correlating the various zones in both feldspars. The increasing water vapor pressure finally exceeded the confining pressure and produced an explosion breccia. Hornblende Lamprophyre dykes cut both the rocks of the Lime Creek stock and strata of the Hazelton group. North of the prospect, the Tertiary (?) noselite trachyte of Table Mountain overlies the Hazelton group. The intrusion is intimately veined by a quartz stockwork in which molybdenite, pyrite, galena, sphalerite, scheelite and many other minerals are found. Sparse amounts of an unknown grey, bladed lead-copper-bismuth-silver sulphosalt were found in a drusy quartz vein. Single crystal rotation and Weissenberg photographs indicate that the unit cell is monoclinic with a = 37.5Å, b = 4.07Å, c = 41.6Å and β = 96.8°.
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