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Southern Alps Cu-Au hydrothermal system, Westland, New Zealand

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Abstract

The Southern Alps of New Zealand is an actively rising mountain belt which displays a thermal anomaly adjacent to the Alpine Fault, the Australian-Pacific plate boundary. Extensive fluid movement occurs in this uplift zone, resulting in metallic vein mineralization. Gold mineralization is confined to greenschist facies rocks, while younger veins in amphibolite facies rocks near the Alpine Fault are enriched in copper. Transport and deposition of metals in this complex hydrothermal system is governed by interaction between rising metamorphic fluids and downward-percolating meteoric fluid. Metamorphic fluids have equilibrated with graphitic schist country rock and are relatively reduced. Infiltration and mixing of meteoric water increases oxygen activity and decreases sulphur activity in the fluid. Oxidised meteoric water heats up and dissolves Cu during downward percolation. This Cu is deposited as the fluid becomes more reduced. Hence, there is a progressive increase in copper content in the middle portions of the hydrothermal system, especially in the more permeable highly fractured rocks near the Alpine Fault.

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References

  1. Allis, R.G., Henley, R.W., Carman, A.F.: The thermal regime beneath the Southern Alps. In: Walcott, R.I., Cresswell, M.M. (eds.) The origin of the Southern Alps. Bull. Royal. Soc. N.Z. 18:79–85 (1979)

  2. Barnes, I., Downes, C.J., Hulston, J.R.: Warm springs, South Island, New Zealand and their potential to yield laumontite. Am Jour. Sci. 278:1412–1427 (1978)

  3. Beane, R.E., Titley, S.R.: Porphyry copper deposits. Part II. Hydrothermal alteration and mineralization. Econ. Geol. 50th Anniv. vol. pp. 235–269 (1981)

  4. Bull, W.J., Copper, A.F.: Uplifted marine terraces along the Alpine Fault, New Zealand. Science 234:1225–1228 (1986)

  5. Craw, D.: Shallow-level penetration of metamorphic fluids in the high uplift rate mountain belt, Southern Alps, New Zealand. Jour. Metam. Geol. 6:1–16 (1987)

  6. Craw, D., Rattenbury, M.S., Johnstone, R.D.: Structural geology and vein mineralization in the Callary River headwaters, Southern Alps, New Zealand. N.Z. Jour. Geol. Geophys. 30:273–286 (1987)

  7. Craw, D., Koons, P.O.: Tectonically induced hydrothermal activity and gold mineralization adjacent to major fault zones. In: Keays, R., Ramsay, R., Groves, D. (eds.) The Geology of Gold Deposits. Econ. Geol. Monograph 6:463–470 (1989)

  8. Crerar, D.A., Barnes, H.L.: Ore solution chemistry. V. Solubilities of chalcopyrite and chalcocite assemblages in hydrothermal solution at 200° to 350°C. Econ. Geol. 71:772–794 (1976)

  9. Ellis, A.J., Mahon, W.A.J.: Chemistry and geothermal systems. New York, Academic Press, 392 pp. (1977)

  10. Grapes, R., Palmer, K.: X-ray fluorescence major and trace element analyses of metabasites, Southern Alps, New Zealand. Dept. of Geology, Victoria University of Wellington, Publ. 24, 16 pp. (1984)

  11. Grapes, R., Watanabe, T., Palmer, K.: X.R.F. analyses of quartzofeldspathic schists and metacherts, Franz Josef-Fox Glacier area, Southern Alps of New Zealand. Dept. of Geology, Victoria University of Wellington, Publ. 25, 11 pp. (1984)

  12. Grindley, G.W.: Structure of the Alpine Schists of south Westland, Southern Alps, New Zealand. N.Z. Jour. Geol. Geophys. 6:872–930 (1963)

  13. Hedenquist, J.W, Henley, R.W.: Hydrothermal eruptions in the Waiotapu geothermal system, New Zealand: their origin, associated breccias and relation to precious metal mineralization. Econ. Geol. 80:1640–1668 (1985)

  14. Hemley, J.J., Cygan, G.L., d'Angelo, WM.: Effect of pressure on ore mineral solubilities under hydrothermal conditions. Geology 14:377–379 (1986)

  15. Henley, R.W., Norris, R.J., Paterson, C.J.: Multistage ore genesis in the New Zealand geosyncline, a history of post-metamorphic lode emplacement. Mineral. Deposita 11:180–196 (1976)

  16. Henley, R.W.: Metals in hydrothermal fluids. Rev. Econ. Geol. 1:115–128 (1984)

  17. Koons, P.O.: Some thermal and mechanical consequences of rapid uplift: an example from the Southern Alps, New Zealand. Earth Plan. Sci. Letters 86:307–319 (1987)

  18. Norris, R.J., Koons, P.O., Cooper, A.F.: Aspects of the South Island collision zone, Central Otago and the West Coast. Geol. Soc. N.Z. Misc. Publ. 37C:39–88 (1987)

  19. Paterson, C.J.: Oxygen isotopic evidence for the origin and evolution of a scheelite ore-forming fluid, Glenorchy, New Zealand. Econ. Geol. 77:1672–1687 (1982)

  20. Roser, B.P.: Comparative studies of copper and manganese mineralization in the Torlesse, Waipapa and Haast Schist Terranes, New Zealand. Unpub. Ph.D. thesis, Victoria University of Wellington, New Zealand (1983)

  21. Seward, T.M.: Thiocomplexes of gold and the transport of gold in hydrothermal ore solutions. Geochim. Cosmochim. Acta 37:379–399 (1973)

  22. Sibson, R.H., White, S.H., Atkinson, B.K.: Fault rock distribution and structure within the Alpine Fault zone, a preliminary account. In: Walcott, R.I., Cresswell, M.M. (eds.) The origin of the Southern Alps. Bull. Royal Soc. N.Z. 18:67–72 (1979)

  23. White, D.E.: Active geothermal systems and hydrothermal ore deposits. Econ. Geol 75th Anniv. Vol. 392–423 (1981)

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Johnstone, R.D., Craw, D. & Rattenbury, M.S. Southern Alps Cu-Au hydrothermal system, Westland, New Zealand. Mineral. Deposita 25, 118–125 (1990). https://doi.org/10.1007/BF00208854

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Keywords

  • Gold Mineralization
  • Meteoric Water
  • Fracture Rock
  • Hydrothermal System
  • Plate Boundary