Skip to main content
SpringerLink
Log in

Geology, alteration and mesothermal Au-Ag-mineralization associated with a volcanic-intrusive complex at Mt. Shamrock-Mt. Ophir, SE Queensland

  • Published:
Mineralium Deposita Aims and scope Submit manuscript

Abstract

Au-Ag mineralization in the Mt-Shamrock — Mt. Ophir area of SE Queensland is related to a geographically-isolated calc-alkaline igneous centre consisting of high level plutonic and minor intrusions emplaced into the eroded remains of a silicic volcanic ediface and its basement. Mineralization occurs in both the igneous rocks and in the Permian siltstone country rocks and is controlled by a NE-trending structure parallel to Late Triassic lineaments. This structure is unrelated to, and younger than the exposed intrusions. Au-Ag-As-rich, Cu-Mo-poor mineralization occurs in breccias and veinlet networks within pervasively altered rocks characterized by silicification and H (sericite), CO2 (calcite-ankerite), Na (albite), B (tourmaline), and S (pyrite) metasomatism. Secondary mineral compositions suggest that most of this alteration occurred at temperatures between 350 ° and 400 °C. The alteration was complex in detail and characterized by multiple hydrothermal events and space and/or time variations of physico-chemical conditions. Although some of these features are similar to prophyry deposits the chemical character of the alteration and mineralization is not typical of Cu-Mo-Au porphyries and has more in common with tectonometamorphic Au deposits formed at considerably greater depths.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Almond, D.C.: Ignimbrite vents in the Sabaloka cauldron, Sudan. Geol. Mag. 108:159–176 (1971)

    Google Scholar 

  • Anovitz, L.M., Essene, E.J.: Phase equilibria in the system CaCO3- MgCO3-FeCO3. J. Petrol. 28:389–414 (1987)

    Google Scholar 

  • Ball, L.C.: On the Stanton Harcourt diggings and the Mt. Shamrock mine. Qld. Geol. Surv. Publ. No. 168:1–8 (1901)

  • Beane, R.E., Titley, S.R.: Porphyry copper deposits part II. Hydrothermal alteration and mineralization. Econ. Geol., 75th Anniversiary Volume, pp. 235–269 (1981)

  • Bird, D.K., Schiffman, P., Elders, W.A., Williams, A.E., McDowell, S.D.: Calci-silicate mineralization in active geothermal systems. Econ. Geol. 79:671–695 (1984)

    Google Scholar 

  • Dunstan, B.: Mt. Shamrock gold mines. Qld. Gov. Min. J. 12:169–173 (1911)

    Google Scholar 

  • Floyd, P.A., Winchester, J.A.: Identification and discrimination of altered and metamorphosed volcanic rocks using immobile elements. Chem. Geol. 21:291–306 (1978)

    Google Scholar 

  • Groves, D.I., Phillips, G.N.: The genesis and tectonic control on Archaean gold deposits of the Western Australian shield — a metamorphic replacement model. Ore Geol. Reviews 2:287–322 (1987)

    Google Scholar 

  • Hall, A.J.: Pyrite-pyrrhotine redox reactions in nature. Mineralog. Mag. 50:223–229 (1986)

    Google Scholar 

  • Handley, G.A., Bradshaw, P.M.D.: The Porgera gold deposit, Papua New Guinea. In: Gold '86, Macdonald, A.J., Ed., pp. 416–424. Willowdale, Ontario, Konsult Internat. Inc. (1986)

    Google Scholar 

  • Henry, D.J., Guidotti, C.V.: Tourmaline as a petrogenetic indicator mineral: an example from the staurolite grade metapelites of NW Maine. Amer. Mineral. 70:1–15 (1985)

    Google Scholar 

  • Monier, G., Robert, J.-L.: Muscovite solid solutions in the system K2O-MgO-FeO-Al2O3-SiO2-H2O: an experimental study a 2 kbar P H2O and comparison with natural Li-free white micas. Mineralog. Mag. 50:257–266 (1986)

    Google Scholar 

  • Morrison, G.W., Teale, G.S., Hodkinson, I.: Geology and gold mineralization at Mount Leyshon, North Queensland. In Proceedings of the Pacific Rim Congress 87, pp. 777–780. Parkville, Victoria, Australasian Institute of Mining and Metallurgy (1987)

    Google Scholar 

  • Murray, C.G.: Metallogeny and tectonic development of the Tasman fold belt system in Queensland. Ore Geol. Reviews 1:315–400 (1986)

    Google Scholar 

  • Mustard, H.: Geology and genesis of the Kidston gold deposit. In: Gold '86, Macdonald, A.J., Ed., pp. 404–415. Willowdale, Ontario, Konsult Internat. Inc. (1986)

    Google Scholar 

  • Nash, C.R.: Permo-Triassic tectonic evolution and metallogenesis of the Rockhampton — Maryborough area, Queensland — A photogeological investigation. Ore Geol. Reviews 1:401–412 (1986)

    Google Scholar 

  • Nesbitt, B.E.: Gold deposit continuum: a genetic model for lode Au mineralization in the continental crust. Geology 16:1044–1048 (1988)

    Google Scholar 

  • Pearce, J.A.: Trace element characteristics of lavas from destructive plate boundaries. In: Andesites, Thorpe, R.S., Ed., pp. 525–548. Chichester, Wiley (1982)

    Google Scholar 

  • Ridgeway, J.E.: Mt. Ophir, Chowey Creek. Qld. Gov. Min. J. 37:3–4 (1936)

    Google Scholar 

  • Sillitoe, R.H.: Some thoughts on gold-rich porphyry copper deposits. Mineral. Deposita 14:161–174 (1979)

    Google Scholar 

  • Sillitoe, R.H.: Ore-related breccias in volcanoplutonic arcs. Econ. Geol. 80:1467–1514 (1985)

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Geology and Key Centre in Economic Geology, James Cook University of North Queensland, Q4811, Townsville, Australia

    P. J. Williams

Authors
  1. P. J. Williams
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Williams, P.J. Geology, alteration and mesothermal Au-Ag-mineralization associated with a volcanic-intrusive complex at Mt. Shamrock-Mt. Ophir, SE Queensland. Mineral. Deposita 26, 11–17 (1991). https://doi.org/10.1007/BF00202358

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00202358

Keywords

Search

Navigation