A fluid inclusion study of quartzite-hosted lode gold mineralization at Athabasca Pass, Central Rocky Mountains, Canada

Fluid inclusions in quartz coeval with native gold in recently discovered auriferous veins in the Athabasca Pass sector of the main ranges of the central Canadian Rocky Mountains have yielded clues to the possible origins of these new mineral occurrences. Gold-bearing veins are hosted by a dominantly siliceous sequence of low-grade quartzites + or - conglomerates and pelites belonging to the Lower Cambrian Gog Group.Microthermometric data indicate that an aqueous fluid of relatively constant composition, containing 2 to 10 equiv wt percent NaCl and up to 11 mole percent CO (sub 2) (+ or -CH (sub 4) , N (sub 2) ), accompanied gold mineralization at between 295 degrees and 330 degrees + or - 20 degrees C and at pressures of > or =900 bars. These data, augmented by earlier geologic and geochemical information, evoke a classification of the Athabasca Pass lodes into the mesothermal, turbidite-hosted class. However the dominantly mature, siliceous clastic host rocks at Athabasca Pass illustrate the potentials of quartzite-dominated domains as potential exploration targets in the search for future mesothermal lode gold systems.