Abstract
Small Archaean, pre-metamorphic layered sill-like intrusions showing “ Stillwatertype” differentiation are widespread in the Eastern Goldfields region of Western Australia. The sills have undergone low-grade metamorphism, but the retention of some original minerals and excellent preservation of primary textures have enabled most of their original features to be reconstructed. Despite their small size in comparison with well known layered intrusions, simple differentiation sequences are developed ranging upwards from dunite and harzburgite through orthopyroxenite, norite, norite-gabbro and gabbro to granophyre and anorthosite. The parent magma for the sills appears to have been rich in MgO (15–18%) and is probably represented by the spatially associated high-Mg basalts found in the region. The complexes are interpreted as being contemporaneous with volcanism and may be high-level emplacements.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Anhaeusser, C. R.: The Barberton Mountain Land, South Africa—a guide to the understanding of the Archaean geology of Western Australia. Spec. Publ. Geol. Soc. Aust. 3, 103–119 (1971).
Bowes, D. R., Skinner, W. R., Wright, A. E.: Petrochemical comparison of the Bushveld igneous complex with some other mafic complexes. Spec. Publ. Geol. Soc. S. Afr. 1, 425–440 (1970).
Clarke, E. de C.: The geology of a portion of the East Coolgardie and North-east Coolgardie Goldfields, including the mining centres of Mt Monger and St Ives. Bull. Geol. Surv. West. Aust. 90 (1925).
Glikson, A. Y.: Primitive Archaean element distribution patterns: chemical evidence and geochemical significance. Earth Planet. Sci. Letts. 12, 309–320 (1971).
Hallberg, J. A.: Geochemistry of Archaean volcanic belts in the Eastern Goldfields region of Western Australia. J. Petrol. 13, 45–56 (1972).
Hallberg, J. A., Williams, D. A. C.: Archaean mafic and ultramafic rock associations in the Eastern Goldfields region of Western Australia. Earth Planet. Sci. Letts. (in press) (1972).
Hess, H. H.: Stillwater igneous complex, Montana, a quantitative mineralogical study. Mem. Geol. Soc. Am. 80 (1960).
Irvine, T. N.: Heat transfer during solidification of layered intrusions. I. Sheets and sills. Can. J. Earth Sci. 7, 1031–1061 (1970a).
Irvine, T. N.: Crystallisation sequences in the Muskox intrusion and other layered intrusions. I. Olivine-pyroxene-plagioclase relations. Spec. Publ. Geol. Soc. S. Afr. 1, 441–476 (1970b).
Jackson, E. D.: Primary textures and mineral associations in the ultramafic zone of the Stillwater complex, Montana. U. S. Geol. Surv. Profess. Papers 358 (1961).
Jackson, E. D.: The cyclic unit in layered intrusions—a comparison of repetitive stratigraphy in the ultramafic parts of the Stillwater, Muskox, Great Dyke and Bushveld complexes. Spec. Publ. Geol. Soc. S. Afr. 1, 391–424 (1970).
McCall, G. J. H.: Some ultrabasic and basic igneous rock occurrences in the Archaean of Western Australia. Spec. Publ. Geol. Soc. Aust. 3, 429–442 (1971).
McCall, G. J. H., Doepel, J. J. G.: Stratiform basic bodies within the Yilmia ophiolites, Western Australia. Proc. Australasian Inst. Mining Met. 231, 67–73 (1969).
Prider, R. T.: “The greenstones” of south-western Australia. J. Roy. Soc. W. Australia 44, 1–9 (1961).
Purvis, A. C., Nesbitt, R. W., Hallberg, J. A.: The geology of part of the Carr Boyd Rocks Complex and its associated nickel mineralisation. Econ. Geol. (in press).
Travis, G. A., Woodall, R., Bartram, G. D.: The geology of the Kalgoorlie Goldfield. Spec. Publ. Geol. Soc. Aust. 3, 175–190 (1971).
Wager, L. R.: Rhythmic and cryptic layering in mafic and ultramafic plutons. In: H. H. Hess and A. Poldervaart (eds.), Basalts, vol. 2, p. 445–482. New York: Interscience 1967.
Wager, L. R., Brown, G. M.: Layered igneous rocks. London: Oliver and Boyd 1968.
Wager, L. R., Brown, G. M., Wadsworth, W. J.: Types of igneous cumulates. J. Petrol. 1, 73–85 (1960).
Williams, D. A. C.: Determination of primary mineralogy and textures in ultramafic rocks from Mt Monger, Western Australia. Spec. Publ. Geol. Soc. Aust. 3, 259–268 (1971).
Williams, D. A. C.: Archaean ultramafic, mafic and associated rocks, Mt Monger, Western Australia. J. Geol. Soc. Aust. (in press) (1972).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Williams, D.A.C., Hallberg, J.A. Archaean layered intrusions of the Eastern Goldfields region, Western Australia. Contr. Mineral. and Petrol. 38, 45–70 (1973). https://doi.org/10.1007/BF00371726
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00371726