Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-23T21:23:03.790Z Has data issue: false hasContentIssue false
  • English
  • Français

Solid solution and cation ordering limits in high-temperature sodic pyroxenes from the Nybö eclogite pod, Norway

Published online by Cambridge University Press:  05 July 2018

M. A. Carpenter  and
D. C. Smith
M. A. Carpenter
Affiliation:
Dept. of Earth Sciences, University of Cambridge, Downing St., Cambridge CB2 3EQ
D. C. Smith
Affiliation:
Grant Institute of Geology, Edinburgh University, West Mains Road, Edinburgh EH9 3JW, Scotland
Get access Rights & Permissions [Opens in a new window]

Abstract

A range of sodic pyroxenes (Jd78Ac2Aug20Jd24Ac9Aug67) from the Nybö eclogite pod, Norway, have been examined by electron-microprobe analysis and by transmission electron microscopy.. Five different microprobes give generally compatible results and new analyses completely fill the natural composition gap in jadeite-rich omphacites with ∼ 3–12% acmite, confirming complete miscibility at high temperatures (⩾ 700 °C). Crystals with omphacite compositions around jadeite: augite = 1:1 contain antiphase domains resulting from the C2/c → P2/n cation ordering transformation. Exsolution microstructures were not observed, from which it is concluded that there are no two-phase regions separating the P2/n and C2/c stability fields at high temperatures (∼ 620–750 °C) and that cooling was too rapid for exsolution to occur in the jadeite/omphacite and omphacite/augite low-temperature solvi. Crystals whose compositions depart significantly from Jd:Aug= 1:1 have weak, diffuse h + k = odd reflections in selected area electron diffraction patterns which are interpreted as being due to short-range ordering outside the true P2/n stability field. The short-range ordering and lack of exsolution are consistent with a previous suggestion that the order/disorder transformation in omphacite is second (or higher) order in character. The average antiphase domain sizes (up to ∼ 3500 Å) are larger than any previously recorded in omphacites and are consistent with available petrological evidence for a long period of annealing at high temperatures before tectonic uplift and cooling.

Type
Research Article
Information
Mineralogical Magazine , Volume 44 , Issue 333 , March 1981 , pp. 37 - 44
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1981

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.)

Footnotes

*

New address: Laboratoire de Minéralogie, Muséum National d'Histoire Naturelle, 6l Rue de Buffon, 75005 Paris, France.

References

Aldridge, L.P., Bancroft, G.M., Fleet, M.E., and Herzberg, C.T. (1978). Am. Mineral. 63, 1107-15.Google Scholar
Autefage, F. (1980). Bull. Mineral. 103, 48–53.Google Scholar
Bence, A.E. and Albee, A.L. (1968). J. Geol. 76, 382–403.CrossRefGoogle Scholar
Bondi, M., Mottana, A., Kurat, A., and Rossi, G. (1978). Rend. Soc. Ital. Mineral. Petrol. 34, 15-25.Google Scholar
Brown, P., Essene, E.J., and Peacor, D.J. (1978). Contrib. Mineral. Petrol. 67, 227-32.CrossRefGoogle Scholar
Brown, W.L. (1973). Unpub. MS. quoted in Newton. R. C., and Fyfe, W.S. (1976). In Bailey, D.K., and Macdonald, R. The evolution of the crystalline rocks. Academic Press, London.Google Scholar
Bryhni, I., Krogh, E., and Griffin, W.L. (1977). Neues Jb. Mineral. Abh. 130, 49–68.Google Scholar
Carpenter, M.A. (1978a). Contrib. Mineral. Petrol. 67, 17-24.CrossRefGoogle Scholar
Carpenter, M.A. (1978b). Phys. Chem. Mineral. 3, 61-2.Google Scholar
Carpenter, M.A. (1979). Am. Mineral. 64, 102-8.Google Scholar
Carpenter, M.A. (1980a). Contrib. Mineral. Petrol. 71, 289-300.CrossRefGoogle Scholar
Carpenter, M.A. (1980b). Am. Mineral. 65, 313-20.Google Scholar
Carpenter, M.A. and Okay, A. (1978). Mineral. MUg. 42, 435-8.CrossRefGoogle Scholar
Champness, P.E. (1973). Am. Mineral. 58, 540-2.Google Scholar
Chen, H., and Cohen, J.B. (1979). Acta Met. 27, 603-11.CrossRefGoogle Scholar
Clark, J.R., and Papike, J.J. (1968). Am. Mineral. 53, 840-68.Google Scholar
Appleman, D.E., and Papike, J.J. (1969). Mineral. Soc. Am. Spec. Pap. 2, 31–50.Google Scholar
Coleman, R.G., and Clark, J.R. (t968). Am. J. Sci. 266, 43–59.CrossRefGoogle Scholar
Curtis, L., Gittins, J., Kocman, V., Rucklidge, J.C., Hawthorne, F.C., and Ferguson, R.B. (1975). Can. Mineral. 13, 62-7.Google Scholar
de Foutaine, D. (1975). Acta Met. 23, 553-71.CrossRefGoogle Scholar
Dobretsov, N.L. (1962). Dokl. Akad. Nauk SSSR, 146, 118-20.Google Scholar
Dobretsov, N.L. Lavrent'yev, Yu. G., and Pospelova, L.N. (1971). Ibid. 201, 152-5.Google Scholar
Essene, E.J., and Fyfe, W.S. (1967). Contrib. Mineral. Petrol. 15, 1-23.CrossRefGoogle Scholar
Fleet, M.E., Herzberg, C.T., Bancroft, G.M., and Aldridge, L.P. (1978). Am. Mineral. 63, 1100-6.Google Scholar
Goldsmith, J.R., and Graf, D.L. (1960). J. Geol. 68, 324-35.CrossRefGoogle Scholar
Goldsmith, J.R. and Heard, H.C. (1961). Ibid. 69, 45-74.Google Scholar
Landau, L.D., and Lifshitz, E.M. (1958). Statistical physics. Addison Wesley.Google Scholar
Lappin, M.A. (1966). Norsk Geol. Tidsskr. 46, 439-96.Google Scholar
Lappin, M.A. (1977). Nature, 269, 730.CrossRefGoogle Scholar
Lappin, M.A. and Smith, D.C. (1978). J. Petrol. 19, 530-84.CrossRefGoogle Scholar
Matsumoto, T., Tokonami, M., and Morimoto, N., 1975. Am. Mineral. 60, 634-41.Google Scholar
Navrotsky, A., and Loucks, D. (1977). Phys. Chem. Mineral. 1, 109-27.CrossRefGoogle Scholar
Onuki, H., and Ernst, W.G. (1969). Mineral. Soc. Am. Spec. Pap. 2, 241-50.Google Scholar
Phakey, P.P., and Ghose, S. (1973). Contrib. Mineral. Petrol. 39, 239-45.CrossRefGoogle Scholar
Rossi, G., Tazzoli, V., and Ungaretti, L. (1978). Proc. XI IMA Meeting, Novosibirsk. Google Scholar
Rossi, G., Ungaretti, L., Mottana, A., and Smith, D.C. (1977). Rend. Soc. Ital. Mineral. Petrol. 33, 853-4.Google Scholar
Rossi, G., Ungaretti, L., Mottana, A., Smith, D.C. and Domeneghetti, C. (1980). Abstracts, 12th IMA General Meeting, Orléans, 187.Google Scholar
Smith, D.C. (1971). Norsk Geol. Tidsskr. 51, 141-7.Google Scholar
Smith, D.C. (1976). Fortsch. Mineral. 54, 94.Google Scholar
Smith, D.C. (1978). Abstracts, IGCP Caledonide Conference, Dublin, 54.Google Scholar
Smith, D.C. (1980a). Abstracts, XXVI Inter. Geol. Congr., Paris, 92.Google Scholar
Smith, D.C. (1980b). Nature, 287, 366-8.CrossRefGoogle Scholar
Smith, D.C., Mottana, A., and Rossi, G. (1980). Lithos, 13, 227-36.CrossRefGoogle Scholar
Statham, P.J. (1976). X-ray Spectrom. 5, 16-28.CrossRefGoogle Scholar
Sweatman, T.R. and Long, J.V.P. (1969). J. Petrol. 10, 332-79.CrossRefGoogle Scholar
Yokoyama, K., Banno, S., and Matsumoto, T. (1976). Mineral. Mug. 40, 773-9.CrossRefGoogle Scholar