Hostname: page-component-5c6d5d7d68-vt8vv Total loading time: 0.001 Render date: 2024-08-14T18:27:03.789Z Has data issue: false hasContentIssue false
  • English
  • Français

Significance of clinopyroxene compositions from the Cudgegong Volcanics and Toolamanang Volcanics: Cudgegong-Mudgee district, NSW, Australia

Published online by Cambridge University Press:  05 July 2018

J. W. Pemberton  and
R. Offler
J. W. Pemberton
Affiliation:
Department of Geology, University of Wollongong, Wollongong, NSW, Australia, 2500
R. Offler
Affiliation:
Department of Geology, University of Newcastle, Newcastle, NSW, Australia, 2308
Get access Rights & Permissions [Opens in a new window]

Synopis

Clinopyroxene phenocrysts and groundmass crystals are relict phases in altered basalt and basaltic andesite lavas, and arenites of the Cudgegong Volcanics and Toolamanang Volcanics, Cudgegong-Mudgee district, New South Wales. Petrography, field relationships and clinopyroxene compositions indicate that basaltic blocks in the latter unit are reworked from the Cudgegong Volcanics. Clinopyroxene phenocrysts show a restricted compositional range and minor Feenrichment from core to rim, features considered indicative of a calc-alkaline parent magma. It is proposed that the Cudgegong Volcanics crystallized under hydrous conditions, at least in the later stages, with rising fO2 resulting in a Fe-Ti oxide crystallizing as a primary phase. The clinopyroxenes are considered to have crystallized at moderate (5–6 kbar) and falling pressures and at minimum temperatures in the range 900 to 1000°C. Coupled substitutions affecting the “other” components in the clinopyroxene structural formula indicate that the ivAl-viFe3+, ivAl-viAl and ivAl-viTi4+ couples are important. The Sofala Volcanics, south of the study area, and the Cudgegong Volcanics are similar in age, petrography and stratigraphic position, and contain relict clinopyroxenes which are chemically similar. This suggests that the units are laterally equivalent and adds further evidence to the proposal that an oceanic island arc system was active in central western New South Wales during the Late Ordovician.

Keywords

clinopyroxenebasaltsarenitesCudgegong VolcanicsToolamanang VolcanicsNew South WalesAustralia
Type
Research Article
Information
Mineralogical Magazine , Volume 49 , Issue 353 , September 1985 , pp. 591 - 599
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1985

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

Aokl, K., and Kushiro, I. (1968) Contrib. Mineral. Petrol. 18, 326-37.Google Scholar
Barton, B.J. (1976) Am. J. Sci. 276, 604-36.Google Scholar
Barton, B.J. and Barron, L.M. (1976) Am. J. Sci, 276, 637-69.Google Scholar
Bender, J.F., Hodges, F.N., and Beaus, A. E. (1978) Earth Planet. Sci. Lett. 41. 277–302.Google Scholar
Best, E.G., and Mercy, E.L.P. (1967) Am. Mineral. 52, 436-75.Google Scholar
Cas, R. (1980) Geol. Soc. Austr. A.S.G. Conference Abstracts 2, 64-5.Google Scholar
Coish, R.A. and Taylor, L.A. (1978) Geol. Soc. AM. Pres. and Abstr. Toronto Heetlng, 382.Google Scholar
Deer, W.A., Howie, R.A., and Zussman, J. (1971) An Introduction to the Rock Forming Minerals. Longman. London.Google Scholar
Ewart, A. (1976) In Trondhjemltes, Dacites and Related Rocks. F. Barker (ed.)Google Scholar
Fodor, R.V. (1971) Earth Planet. Sci. Lett, 11, 385-90.CrossRefGoogle Scholar
Fodor, R.V., Keil, K., and Bunch, T.E. (1975) Contrib. Mineral. Petrol. 50, 173-95.CrossRefGoogle Scholar
Garcia, M.O. (1978) Earth sci. Rev. 14, 147-65.CrossRefGoogle Scholar
Gibb, F.G.F. (1973) J. Petrol. 14-2, 203-30.Google Scholar
Gill, J.B. (1981) Orogenic Andesltes and Plate Tectonics. Spriztger-Verlag, New York.CrossRefGoogle Scholar
Green, T.H. (1972) Cotrib. Mineral. Petrol. 34. 150-66.CrossRefGoogle Scholar
Grove, T.L., Gerlach, D.C., and Sando, T.W. (1982) Contrib. Mineral. Petrol. 80, 160-82.CrossRefGoogle Scholar
Hellman, P.L., Smith, R.E., and Henderson, F. (1977) Contrib. Mineral. Petrol. 63. 135-64.Google Scholar
Huekenholz, H.G., Schairer, J.F., and Yoder, H.S. Jnr. (1969) Mineral. Soc. Am. Spec. Pep. 2, 163-77.Google Scholar
Kay S., Mahlborg, Kay, R.W., Brueckner, H.K., and Rubenstone, J.L. (1983) Contrib, Mineral. Petrol. 82-1, 99–116.CrossRefGoogle Scholar
Leterrier, J., Maury, R.C., Thonon, P., Girard, D., and Marchal, M. (1982) Earth Plant. Sci. Left. 59, 139-54.CrossRefGoogle Scholar
Lindsley, D.H. (1983) Am. Mineral. 68, 677-93.Google Scholar
Lindsley, D.H. and Andersen, D.J. (1983) J. Geophys. Res. 88, 887–906.CrossRefGoogle Scholar
Marcelot, G., Maury, R.C., and Le Fevre, C. (1983) Lithos 16, 133-51.Google Scholar
Mevel, C., and Velde, B. (1976) Earth Planet. Sci. Lett. 32, 158-66,CrossRefGoogle Scholar
Morse, S.A. (1980) Basalts and Phase Diagram Springer-Verlag, New York.CrossRefGoogle Scholar
Mueller, R,F., and Saxena, S.K, (1977) Chemical Petrology Springer-Verlag, New York.CrossRefGoogle Scholar
Mullen, K.D. (1983) Earth Planet. Sci. Lett. 62, 53–62.CrossRefGoogle Scholar
Nash, W.P., and Wilkinson, J.F.G. (1970) Contrib. Mineral, Petrol, 28, 261-69Google Scholar
Nisbet, E.C., and Pearce, J.A. (1977) Coutrib. Mineral. Petrol. 65, 149-60.CrossRefGoogle Scholar
Offler, R., and Pemberton, J.W. (1983) Geol. Soc. Anstr. Ahstr. 9, 62.Google Scholar
Osborn, E.F. (1959) Am. J. Sci. 257, 609-47.CrossRefGoogle Scholar
Packham, G.H. (1968) Proc. Linnean Soe. New South Wales 93, 111-63.Google Scholar
Papike, J.J., Cameron, K.L., and Baldwin, K. (1974) Geol. Sue. Am. Abstr. 6, 1033-4.Google Scholar
Pemberton, J.W. (1980) J. Proc. R. Soc. New South Wales 113, 49–62.Google Scholar
Pickett, J.W. (1982) Geol. Surv. New South Wales Unpubl. Palaeo. Report 82/10.Google Scholar
Poldervaart, A., and Hess, H.H. (1951) J. Geol. 59, 472-89.CrossRefGoogle Scholar
Powell, C.MnA. (1982) Geol. Soc. Austr. Symposium Abstr. 6, 6–7.Google Scholar
Reed, S.J.B. and Ware, N.G. (1925) J. Petrol. 16. 499–519.CrossRefGoogle Scholar
Robinson, P. (1980) In Reviews in Mineralogy : vol. 7 Fyrozeaes. C.T. Prewitt (ed.). 419-90.Google Scholar
Scheibner, E. (1978) Teetonophysics 48, 153-7.CrossRefGoogle Scholar
Smith, R.E. (1969) J. Petrol, 9, 191–219.CrossRefGoogle Scholar
Smith, R.E. and Smith, S.E. (1976) Earth Planet. Scl. Lett. 32, 114-20.CrossRefGoogle Scholar
Traey, R.J., and Robinson, P. (1977) Am. Mineral. 62, 634-45.Google Scholar
Vieten, K. (1980) Neues. jahrb. Mineral. Abh. 140, 54–88.Google Scholar
Wager, L.R. and Brown, G.M. (1968) Layered Igneous Rocks. Oliver Boyd, Edinburgh.Google Scholar
Wass, S.Y. (1979) Lithos 12, 115-32.CrossRefGoogle Scholar