Abstract
Homogenization temperatures and salinity data are presented for fluid inclusions from hydrothermal gangue minerals (quartz and fluorite) associated with porphyry wolframite-molybdenite-arsenopyrite-sphaleritebismuth-chalcopyrite-cassiterite mineralization within the Fire Tower ore zone, Mt Pleasant, New Brunswick. The data indicate that ore mineral precipitation occurred within a temperature range of 260° to 490°C from moderate to high salinity (10–42 wt% NaCl equivalent) aqueous fluids. Two stages of hydrothermal activity characterized by high (>30 wt% NaCl equivalent) salinity fluids are recognized; one which occurred at relatively high temperature (350°–490°C); and one which took place at lower temperature (180°–250°C). The high salinity, high temperature stage is interpreted to be the result of resurgent boiling. Dilution of these early fluids by convecting meteoric water resulted in low to moderate salinity fluids, which dominate the inclusion population. The low temperature, high salinity fluid inclusions are interpreted to represent late residual fluids derived from boiling which occurred as a result of a change in the pressure regime from dominantly lithostatic to hydrostatic conditions.
Similar content being viewed by others
References
Ahmad, S.N., Rose, A.W.: Fluid inclusions in porphyry and skarn ore at Santa Rita, New Mexico. Econ. Geol. 75, 229–250 (1980)
Atkinson, J.R., Kooiman, G., Coates, H.J.: Geology of Mount Pleasant Tungsten, New Brunswick. Can. Min. J. vol. 102, 73–75 (1981)
Burnham, C.W.: Magmas and hydrothermal fluids. In: Barnes, H.L., ed., Geochemistry of Hydrothermal Ore Deposits, 2nd ed. pp 71–136, New York, Wiley Interscience 1979
Burt, D.M.: Acidity-salinity diagrams-application to greisen and porphyry deposits. Econ. Geol. 76, 832–843 (1980)
Cathles, I.M.: An analysis of the cooling of intrusives by groundwater convection which includes boiling. Econ. Geol. 73, 804–826 (1977)
Chivas, A.R., Wilkins, R.W.T.: Fluid inclusion studies in relation to hydrothermal alteration and mineralization at the Koloula porphyry copper prospect, Guadalcanal. Econ. Geol. 72, 153–169 (1977)
Crawford, M.L.: Phase equilibria in aqueous fluid inclusions. In: Hollister, L.S., Crawford, M.L. eds., M.A.C. short course in fluid inclusions: applications to petrology. pp 75–100, Calgary 1981
Cunningham, C.G.: Pressure variation as a mechanism for localizing hydrothermal ore deposits (abs.): Geol. Assoc. Canada Ann. Mtg. 1977, Program with abstracts, v. 2, p. 14 (1977)
Dagger, G.W.: Genesis of the Mt Pleasant tungsten-molybdenumbismuth deposit, New Brunswick, Canada. Inst. Mining Met. Trans. 81, B 73–102 (1972)
Hall, W.E., Friedman, I., Nash, J.T.: Fluid inclusion and light stable isotope study of the Climax molybdenum deposits, Colorado. Econ. Geol. 69, 884–901 (1974)
Henley, R.W., McNab, A.: Magmatic vapour plumes and groundwater interaction in porphyry copper emplacement. Econ. Geol. 73, 1–20 (1978)
Kilinc, I.A., Burnham, C.W.: Partioning of chloride between a silicate melt and coexisting aqueous phase from 2 to 8 Kilobars. Econ. Geol. 67, 231–235 (1972)
Kogarko, L.N.: Role of volatiles: in Sorensen, H. ed., The alkaline rocks: London, John Wiley and Sons, 474–487 (1974)
Luth, W.C.: Granitic rocks: In: Bailey, D.K., MacDonald, R.A., eds., The evolution of the crystalline rocks 484 p., New York, Academic Press 1976
Nash, T.J., Cunningham Jr., C.G.: Fluid inclusion studies of the porphyry copper deposit at Bagdad, Arizona. our. Research U.S. Geol. Survey, vol. 2, no. 1, 31–34 (1974)
Parrish, I.S., Tully, J.V.: Porphyry tungsten zones at Mt Pleasant, New Brunswick. C.I.M. Bull. June 1978, 93–100 (1978)
Petruk, W.: The tungsten-bismuth-molybdenum deposit of Brunswick Tin Mines Ltd.: its mode of occurrence mineralogy and amenability to mineral beneficiation. C.I.M. Bull. April 1973, 113–130 (1973)
Potter, R.W., Clynne, M.A., Brown, D.L.: Freezing point depression of aqueous sodium chloride solutions. Econ. Geol. 73, 284–285 (1978)
Potter, R.W., Babcock, R.S., Brown, D.L.: A new method for determining the solubility of salts in aqueous solutions at elevated temperatures. Jour. Research U.S. Geol. Survey, vol. 5: no. 3, 389–395 (1977)
Potter, R.W., Brown, D.L.: The volumetric properties of aqueous sodium chloride solutions from 0° to 500°C at pressures up to 2,000 bars on a regression of the available literature data: U.S. Geol. Survey open file report, 31 p. (1975)
Pouliot, G., Barondeau, B., Sauve, P., Davis, M.: Distribution of alteration minerals and metals in the Firetower zone at Brunswick Tin Mines Ltd., Mt Pleasant area N.B. Can. Mineralogist, 16, 223–237 (1978)
Roedder, E., Bodnar, R.J.: Geologic pressure determinations from fluid inclusion studies. Ann. Rev. Earth Planet. Sci., 8, 263–301 (1980)
Ruitenberg, A.A.: Metallization episodes related to tectonic evolution, Rolling Dam and Mascarene-Nepepis belts N.B. Econ. Geol. 67, 434–444 (1972)
Tait, S.: Breccias of Mt Pleasant. MSc. Thesis. McGill University (unpubl.) (1964)
Whitney, J.A.: Vapour generation in a quartz monzonite magma: A synthetic model with applications to porphyry copper deposits. Econ. Geol., 70, 346–358 (1975)
Author information
Authors and Affiliations
Additional information
Contribution 85-1 of the Mineral Exploration Research Institute, P.O. Box 6079, Station A, Montreal, Quebec H3C 3A7, Canada
Rights and permissions
About this article
Cite this article
Davis, W.J., Williams-Jones, A.E. A fluid inclusion study of the porphyry-greisen, tungsten-molybdenum deposit at Mount Pleasant, New Brunswick, Canada. Mineral. Deposita 20, 94–101 (1985). https://doi.org/10.1007/BF00204317
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00204317