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Complex sequential pyroxene growth in tholeiitic hypabyssal rocks from southern West Greenland

Published online by Cambridge University Press:  05 July 2018

R. P. Hall
Affiliation:
Department of Geology, Portsmouth Polytechnic, Burnaby Road, Portsmouth, PO1 3QL
D. J. Hughes
Affiliation:
Department of Geology, Portsmouth Polytechnic, Burnaby Road, Portsmouth, PO1 3QL
C. R. L. Friend
Affiliation:
Department of Geology and Physical Sciences, Oxford Polytechnic, Headington, Oxford OX3 0BP

Abstract

Chemically complex pyroxenes which occur in early Proterozoic tholeiitic dolerite dykes in southern West Greenland have been investigated using back-scattered electron (BSE) imagery, X-ray mapping and electron microprobe analysis. A wide variety of compositions occur within individual pyroxene grains in these rocks. They can be explained by simultaneous nucleation of different pyroxenes, the evolution of domains around these nucleii as a response to differential chemical gradients and the sequential precipitation of different pyroxenes at progressively lower temperatures. As an example, the individual grains in one dyke sample contain domains of bronzite, hypersthene, magnesium pigeonite, augite, and subcalcic augite. Olivine in this sample varies in composition from Fo70 to Fo33, although individual grains are only weakly zoned. The wide variation in pyroxene and olivine compositions suggests ranges of crystallization temperatures from c.1250° to as low as 825°C. Such compositionally variable pyroxenes are possibly characteristic of hypabyssal tholeiitic rocks.

Type
Petrology
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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References

Allaart, J.H. (1976) In Geology of Greenlan.(A. Escher and W. S. Watt, eds.). GGU, Copenhagen, pp. 121-51.Google Scholar
Arndt, N.T., and Fleet, M.E. (1979) Am. Mineral. 64, 856-64.Google Scholar
Bence, A.E., Papike, J.J., and Lindsley, D.H. (1971) In Proceedings of the second lunar science conferenc. vol. 1 (A. A. Levinson, ed.). MIT Press, Cambridge, pp. 559-74.Google Scholar
Boyd, F.R. (1971) Carnegie Inst. Wash. Yearb.69, 216-30.Google Scholar
Boyd, F.R.and Smith, D. (1971) J. Petrol. 12, 439-65.CrossRefGoogle Scholar
Brown, G.C. Hughes, D.J., and Esson, J. (1973) Chem. Geol. 11, 223-9.CrossRefGoogle Scholar
Campbell, I.H., and Nolan, J. (1974) Contrib. Mineral. Petrol. 48, 205-19.CrossRefGoogle Scholar
Carmichael, I.S.E. (1967) Am. Mineral. 52, 1815-41.Google Scholar
Chadwick, B. (1969) Tectonophys. 8, 247-64.CrossRefGoogle Scholar
Chadwick, B. and Coe, K. (1983) (compilers) 1:100000 scale geological map, Buksefjorden, 63V1 Nord.Geol. Surv. Greenland.Google Scholar
Dawes, P.R. (1970) Rapp. Gronlands geol. Unders. 29, 60.pp.Google Scholar
Dowty, E. (1980) In Physics ofmagmatic processe.(R. B. Hargraves, ed.). Princeton Univ. Press, Princeton, pp. 419-85.CrossRefGoogle Scholar
Evensen, N.M., Hamilton, P.J., and O'Nions, R.K. (1978) Geochim. Cosmochim. Acta. 42, 1199-212.CrossRefGoogle Scholar
Ewart, A. (1976) Contrib. Mineral. Petrol. 58, 1-22.CrossRefGoogle Scholar
Fodor, R.V. (1971) Earth Planet. Sci. Lett. 11, 385-90.CrossRefGoogle Scholar
Gamble, R.P., and Taylor, L.A. (1980) Ibid. 47, 21-33.Google Scholar
Garcia, M.O. (1978) Earth Sci. Rev. 14, 147-65.CrossRefGoogle Scholar
Gasparik, T. (1984) Contrib. Mineral. Petrol. 87, 87-97.CrossRefGoogle Scholar
Gibb, F.G.F. (1974) Mineralg. Mag. 39, 641-53.CrossRefGoogle Scholar
Grove, T.L., Gerlach, D.C. and Sando, T.W. (1982) Contrib. Mineral. Petrol. 80, 160-82.CrossRefGoogle Scholar
Haggerty, S.E. (1978) Geophys. Res. Lett. 5, 443-6.CrossRefGoogle Scholar
Hall, R.P., Hughes, D.J., and Friend, C.R.L. (1985) J. Petrol. 26, 253-82.CrossRefGoogle Scholar
Huebner, J.S., and Turnock, A.C. (1980) Am. Minera. 65, 225-71.Google Scholar
Irvine, T.N., and Baragar, W.R.A. (1971) Can. J. Earth Sci. 8, 523-48.CrossRefGoogle Scholar
Kalsbeek, F., and Taylor, P.N. (1985) Contrib. Mineral. Petrol. 89, 307-16.CrossRefGoogle Scholar
Klein, C, Jnr., Drake, J.C. and Frondel, C. (1971) In Proceedings of the second lunar science conferenc. vol. 1 (A. A. Levinson, ed.). MIT Press, Cambridge, pp. 265-84.Google Scholar
Kushiro, I., Nakamura, Y., Kitayama, K., and Akimoto, S-I. (1971) Ibid. pp. 481-96.Google Scholar
Lindsley, D.H. (1983) Am. Mineral. 68, 477-93.Google Scholar
Lofgren, G. (1980) In Physics ofmagmatic processe.(R. B. Hargraves, ed.). Princeton Univ. Press, pp. 487551.CrossRefGoogle Scholar
Mori, T. (1978) J. Petrol. 19, 45-65.CrossRefGoogle Scholar
Mueller, R.F. (1969) Hydration, oxidation, and the origin of the calc-alkali series.NASA Springfield, 27 pp.Google Scholar
Murase, T., and McBirney, A.F. (1970) Science. 167, 1491-3.CrossRefGoogle Scholar
Myers, J.S. (1980) (compiler) 1:100000 scale geological map, Sinarssuk, 63V2 Syd.Geol. Surv. Greenland. (1982) (compiler) 1:100000 scale geological map, Graedefjord, 63V1 Syd.Geol. Surv. Greenland.Google Scholar
Nwe, Y.Y. (1975) Contrib. Mineral. Petrol. 49, 285-300. (1976) Ibid. 55, 105-26.CrossRefGoogle Scholar
Osborn, E.F. (1959) Am. J. Sci. 257, 609-47.CrossRefGoogle Scholar
Papike, J.J. (1980) In Reviews in mineralogy, vol. 7, Pyroxene.(C. T. Prewitt, ed.). Mineral. Soc. Am., Washington, pp. 495525.CrossRefGoogle Scholar
Poldervaart, A., and Hess, H.H. (1951) J. Geol. 59, 472-89.CrossRefGoogle Scholar
Prewitt, C.T. (1980) (ed.) Reviews in mineralogy, vol. 7, Pyroxene. Mineral. Soc. Am., Washington, 525 pp.CrossRefGoogle Scholar
Rivalenti, G. (1975) Can. J. Earth Sci. 12, 721-30.CrossRefGoogle Scholar
Wager, L.R., and Brown, G.M. (1968) Layered igneous rock. Oliver and Boyd, London, 588 pp.Google Scholar
Williams, H.R. (1976) Geol. Mag. 113, 77-82.CrossRefGoogle Scholar
Wilson, A.D. (1955) Bull. geol. Surv. G.B. 9, 55-8.Google Scholar