Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-19T05:01:15.825Z Has data issue: false hasContentIssue false
  • English
  • Français

Unusual sulphide replacement textures in altered olivine-rich rocks of the Bulong Complex near Kalgoorlie, Western Australia

Published online by Cambridge University Press:  05 July 2018

P. G. Moeskops  and
G. R. Davis
P. G. Moeskops
Affiliation:
The Australian Mineral Development Laboratories, Frewville, South Australia, 5063
G. R. Davis
Affiliation:
Department of Mining Geology, Imperial College of Science and Technology, London, S.W.7
Get access Rights & Permissions [Opens in a new window]

Summary

Unusual replacement-type sulphide mineralization occurs in the northern part of the Bulong Complex, about 30 km east of Kalgoorlie, Western Australia. The mineralization is non-economic (up to 0·5% Ni, 0·4% Cu, 0·1% Co, and 8·6% S) and occurs in altered unlayered olivine-rich rocks immediately above a thin sheet-like inclusion of country rock. The supergene-modified primary opaque assemblage pyrrhotine-magnetite-pyrite-chalcopyrite-(pentlandite) is texturally unusual in that the opaques are largely pseudomorphic after primary olivine grains, mainly within irregular fracture networks in a manner similar to ‘early’ serpentine. Textural relations between opaques and silicates indicate that the mineralization was introduced during the early stages of serpentinization prior to the onset of deformation and regional metamorphism. Monoclinic pyrrhotine is the main opaque phase, with some grains containing relict cores of the hexagonal variety. Magnetite associated with the mineralization is Ni-poor (< 0·1% Ni) compared with ‘serpentinization magnetite’ from elsewhere in the Bulong Complex, which contains 0·5–0·8% Ni. As the mineralization was intersected at relatively shallow depth, supergene alteration effects are evident; pyrrhotine is locally altered to pyrite and marcasite (texturally and chemically distinct from the primary pyrite), and pentlandite is largely replaced by cupriferous violarite.

Textural features and consideration of phase relations in the system Cu-Fe-S-O suggest that the mineralization is of low-temperature (350± °C) hydrothermal origin. By contrast, the more commonly developed Fe-Ni-Cu sulphide mineralization of the Kalgoorlie region is generally considered to be of high-temperature (1200± °C) magmatic origin.

Type
Research Article
Information
Mineralogical Magazine , Volume 41 , Issue 320 , December 1977 , pp. 473 - 479
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1977

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Arnold, (R. G.), 1966. Mixtures of hexagonal and monoclinic pyrrhotite and the measurement of metal content of pyrrhotite by XRD. Am. Mineral. 51, 1221-7.Google Scholar
Chamberlain, (J. A.), 1966. Sulphides in the Muskox Intrusion. Can. J. Earth Sci. 4, 105-53.CrossRefGoogle Scholar
Clark, (A. H.), 1966. Stability field of monoclinic pyrrhotite. Appl. Earth Sci., Trans. Instn. Min. Metall., Sect. B, 75, B232-5.Google Scholar
Desborough, (G. A.) and Carpenter, (R. H), 1965. Phase relations of pyrrhotite. Econ. Geol. 60, 7, 1431-50.CrossRefGoogle Scholar
Fkzhugh, (E. G.) and Seidel, (D. C), 1966. Formation of nickel and iron sulphides from silicates at moderate temperatures. Geol. Soc. Am. Assoc, Meeting 68, Abstr. Google Scholar
Genkin, (A.), 1971. Some replacement phenomena in copper-nickel sulphide ores. Miner. Deposita, 6, 348–55.CrossRefGoogle Scholar
Haapala, (P. S.), 1969. Fennoscandian nickel deposits. Econ. Geol, Monogr. 4, 262–75.Google Scholar
Kilburn, (L. C), Wilson, (H. D. B.), Graham, (A. R.), Cruga, (Y.), Coats, (C. J. A.), and Scoates, (R. F. J.), 1969. Nickel sulphide ores related to ultrabasic intrusions in Canada. Econ. Geol, Monogr. 4, 276–93.Google Scholar
Kullerud, (G.), Buseck, (B. R.), and Troften, (P. F.), 1963. Heating experiments on monoclinic pyrrhotites. Carnegie Inst. Yearb. 62, 210–13.Google Scholar
Martin, (B.), and Fyfe, (W. S.), 1970. Some experimental and theoretical observations on the kinetics of hydration reactions with particular reference to serpentinisation. Chem. Geol. 6, 185–202.CrossRefGoogle Scholar
Moeskops, (P. G.), 1973. The Bulong Serpentinite and environments of nickel mineralisation near Kalgoorlie, Western Australia. Unpub. Ph.D. thesis, Imperial College, Lond. Univ.Google Scholar
Moeskops, (P. G.), 1975. Cupriferous violarites from the Bulong Complex, near Kalgoorlie, Western Australia. Amdel Bull. 20, 19–33.Google Scholar
Naldrett, (A. J.), 1966. The role of sulphurisation in the genesis of iron-nickel deposits of the Porcupine District, Ont. Trans. Can. Inst. Min. Metall. 69, 147–55.Google Scholar
Philpotts, (A. R.), 1961. Textures of the Ungava nickel ores. Can. Mineral 6, 680–8.Google Scholar
Taylor, (L. A.) and Kullerud, (G.), 1970. Mineral assemblages in the Cu-Fe-S-O system. Carnegie Inst. Wash. Yearb. 69, 315–18.Google Scholar
Turner, (F. J.) and Verhoogen, (J.), 1960. Igneous and Metamorphic Petrology. McGraw-Hill, London.Google Scholar
Wager, (L. R.) and Vincent, (E. A.), 1957. Sulphides in the Skaergaard Instrusion, East Greenland. Econ. Geol. 8 (52), 855-95.CrossRefGoogle Scholar
Williams, (I. R.), 1969. Structural layering in the Kurnalpi 1:250,000 sheet area, Kalgoorlie region. W. Aust. Geol. Surv. Ann. Rep. Google Scholar