Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-12-03T19:24:35.411Z Has data issue: false hasContentIssue false
  • English
  • Français

Petrology and stratigraphy of some texturally well preserved thin komatiites from Kambalda, Western Australia

Published online by Cambridge University Press:  01 May 2009

B. Thomson
B. Thomson
Affiliation:
Upper Kennerty Mills Cottage, Kennerty Mills Road, Peterculter, Aberdeen AB1 OLR, Scotland, U.K.
Get access Rights & Permissions [Opens in a new window]

Abstract

Archaean komatiite volcanics at Kambalda, Western Australia have been metamorphosed to upper greenschist–lower amphibolite grade and have experienced intense though heterogeneously developed polyphase deformation. Despite this, preservation of igneous textural features is often good, particularly in areas which underwent only ‘static style’ metamorphism. Thin lavas from the Tripod Hill Member of the Kambalda Komatiite Formation over the western margin of the Hunt nickel shoot display textural elements and facies variations which are virtually identical to those found in fresher thin komatiite sequences in other Archaean greenstone belts. Four principal flow profile (facies) types are defined, comprising nine subtypes. These represent stages in a facies continuum, ranging from ‘mature’ profiles which comprise thick spinifex textured tops and close packed cumulate bases through to massive, jointed ‘immature’ profiles devoid of mesoscopic spinifex texture. The causes of textural diversity within and between profiles are many and complex. However, facies variations can be attributed mainly to the effects of lava velocity at the time of major heat loss, combined with relative lateral position within any flow. The most mature textural (and geochemical) profiles developed in parts of lavas which had become ponded prior to major heat loss, whereas the least evolved profiles developed along the lateral margins (levees) of moving lavas. The study area komatiites occur as alternating stacks of flows of similar type. This stratigraphy records temporal and spatial shifts in the locus of lava ponding over the western margin of the Hunt nickel shoot. Such shifts may have been caused by irregularities in the underlying volcanic topography and/or by synvolcanic faulting and subsidence.

Type
Articles
Information
Geological Magazine , Volume 126 , Issue 3 , May 1989 , pp. 249 - 261
Copyright
Copyright © Cambridge University Press 1989

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

Arndt, N. T. 1986. Differentiation of komatiite flows. Journal of Petrology 27, 279–301.CrossRefGoogle Scholar
Arndt, N. T., Naldrett, A. J. & Pyke, D. R. 1977. Komatiitic and iron rich tholeiitic lavas of Munro Township, northeast Ontario. Journal of Petrology 18, 319–69.CrossRefGoogle Scholar
Barnes, R. G., Lewis, J. D. & Gee, R. D. 1974. Archaean ultramafic lavas from Mount Clifford. Report of Geological Survey of Western Australia, pp. 59–70.Google Scholar
Cowden, A. (in press). Emplacement of komatiite lava flows and associated nickel sulphides at Kambalda, Western Australia. Economic Geology.Google Scholar
Cowden, A. & Archibald, N. J. (in prep.) Kambalda–Kalgoorlie stratigraphy: Evidence for volcanic cycles and structural repetition in Archaean greenstones.Google Scholar
Donaldson, C. H. 1982. Spinifex-textured komatiites: a review of textures, compositions and layering. In Komatiites (eds Arndt, N. T. & Nisbet, E. G.), pp. 213–44. London: George Allen and Unwin.Google Scholar
Gresham, J. J. 1986. Depositional environments of volcanic peridotite-associated nickel sulphide deposits with special reference to the Kambalda dome. In Geology and Metallogeny of Copper Deposits (eds Friedrich, G. H., Genkin, A. D., Naldrett, A. J., Ridge, J. D., Sillitoe, R. H.& Yokes, F. M.), pp. 63–90. Berlin, Heidelberg:Springer-Verlag.CrossRefGoogle Scholar
Gresham, J. J. & Loftus-Hills, G. D. 1981. The geology of the Kambalda nickel field, Western Australia. Economic Geology 76, 1373–1416.CrossRefGoogle Scholar
Harrison, T. M. & Watson, E. B. 1984. The behaviour of apatite during crustal anatexis: equilibrium and kinetic considerations. Geochimica el Cosmochimica Acta 48, 1467–77.CrossRefGoogle Scholar
Huppert, H. E. & Sparks, R. S. J. 1985. Komatiites I: Eruption and flow. Journal of Petrology 26, 694–725.CrossRefGoogle Scholar
Irvine, T. N. 1980. Magmatic infiltration metasomatism, double diffusive fractional crystallization, and adcumulus growth in the Muskox intrusion and other layered intrusions. In Physics of Magmatic Processes (ed. Hargraves, R. B.), pp. 325–83. New Jersey: Princeton University Press.CrossRefGoogle Scholar
Irvine, T. N. 1987. Processes involved in the formation and development of layered igneous rocks. In Origins of Igneous Layering (ed. Parsons, I.), pp. 649–56 (App. II). Dordrecht: Reidel.Google Scholar
Jolly, W. T. 1982. Progressive metamorphism of komatiite lavas and related Archaean lavas of the Abitibi area, Canada. In Komatiites (eds Arndt, N. T. & Nisbet, E. G.), pp. 213–44. London: George Allen and Unwin.Google Scholar
Lajoie, J. & Gelinas, L. 1978. Emplacement of Archaean peridotitic komatiites in La Motte Township, Quebec. Canadian Journal of Earth Sciences 15, 672–77.CrossRefGoogle Scholar
Parsons, I. & Becker, S. M. 1987. Layering, compaction and post-magmatic processes in the Klokken intrusion. In Origins of Igneous Layering (ed. Parsons, I.), pp. 29–92. Dordrecht: Reidel.CrossRefGoogle Scholar
Pyke, D. R., Naldrett, A. J. & Eckstrand, O. R. 1973. Archaean ultramafic flows in Munro Township, Ontario. Geological Society of America Bulletin 84, 955–78.2.0.CO;2>CrossRefGoogle Scholar
Thomson, B. 1989. B1 subdivisions of thin komatiites from Kambalda, Western Australia. Geological Magazine 126, 263–70.CrossRefGoogle Scholar
Turner, J. S., Huppert, H. E. & Sparks, R. S. J. 1986. Komatiites II: Experimental and theoretical investigations of post-emplacement cooling and crystallization. Journal of Petrology 27, 397–437.CrossRefGoogle Scholar