Hostname: page-component-848d4c4894-p2v8j Total loading time: 0.001 Render date: 2024-05-18T11:56:49.617Z Has data issue: false hasContentIssue false
  • English
  • Français

The biotite-phlogopite series in fenites from the Loe Shilman carbonatite complex, NW Pakistan

Published online by Cambridge University Press:  05 July 2018

I. Mian  and
M. J. Le Bas
I. Mian
Affiliation:
Department of Geology, The University, Leicester LE1 7RH, UK
M. J. Le Bas
Affiliation:
Department of Geology, The University, Leicester LE1 7RH, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

The Loe Shilman carbonatite sheet complex comprises an extensive amphibole sovite which is intruded by minor biotite sovite and amphibole ankeritic carbonatite. The carbonatites have fenitized the country rocks to form a metasomatic zone c. 100 m wide of alternating mafic and felsic mica-bearing banded fenites which grade into slates and phyllites. Phlogopite-rich micas occur nearest to the carbonatite contact. The biotites occur in K-feldspar + albite ± Na-amphibole ± aegirine and ± phengite fenites produced by the intrusion of the early amphibole sovite. Aegirine buffered the iron distribution and the biotites became more magnesian. Veins cross-cutting the fenites consist of biotite and/or Ba-bearing K-feldspar, and are interpreted to result from solutions emanating from the biotite sovite. The ankeritic carbonatite is responsible for the formation ofphlogopite in the fenites in a c. 3 m wide zone adjacent to the carbonatite, and evidently are the result of fenitizing fluids rich in Mg. Chemical equations calculated to balance the reactions interpreted to have taken place in the fenites suggest that about 10% of the Al and Si in the protolith was mobilized and moved towards the carbonatites during fenitization, and that the fenitizing solutions were strongly alkaline and oxidizing.

Keywords

biotitephlogopitefenitecarbonatiteLoe ShilmanPakistan
Type
Mineralogy
Information
Mineralogical Magazine , Volume 51 , Issue 361 , September 1987 , pp. 397 - 408
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

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

Bryan, W.B., Finger, L.W., and Chayes, F. (1969) Science. 163, 9267.CrossRefGoogle Scholar
Cerny, P., and Burt, D.M. (1984) in Micas(Bailey, S.W., ed.). Reviews in Mineralog. 13, Min. Soc. Am. 257 91.Google Scholar
Cooper, A.F. (1971) Geol. Soc. Am. Ball. 82, 132-740.Google Scholar
Carrie, K.L., and Ferguson, J. (1971) Can. J. Earth Sci. 8, 498-517.CrossRefGoogle Scholar
Deer, W.A., Howie, R.A., and Zussman, J. (1963) Rock forming minerals, 2. Longman, London.Google Scholar
Gittins, J., and McKie, D. (1980) Lithos, 13, 215.CrossRefGoogle Scholar
Gittins, J., and McKie, D. Allan, C.R., and Cooper, A.F. (1975) Geol. Mag. 112, 503-7.CrossRefGoogle Scholar
Guidotti, C.V. (1984) In Micas (Bailey, S.W., ed.). Reviews in Mineralog. 13, Min. Soc. Am. 357-455.Google Scholar
Jan, M.Q., Kamal, M., and Qurreshi, A.A. (1981) Geol. Bull. Univ. Peshawar, 14, 2943.Google Scholar
Kempe, D.C.R., and Jan, M.Q. (1970) Geol. Mag. 107, 3958.CrossRefGoogle Scholar
Kresten, P., and Morogan, V. (1986) Lithos, 19, 27-42.CrossRefGoogle Scholar
Le Bas, M.J. (1977) Carbonatite-Nepheline Volcanism, Wiley, London.Google Scholar
Mian, I., and Rex, D.C. (in press) Age and nature of carbonatite emplacement in NW Pakistan. Geol. Rundschau. Google Scholar
McKie, D. (1966) Fenitization of Basic Rocks in Carbonatites (O. F. Tuttle and J. Gittins, eds.), 261-94. Wiley, London.Google Scholar
Mian, I., and Le Bas, M.J. (1986) Mineral Mag. 50, 187-97.CrossRefGoogle Scholar
Nockolds, S.R. (1947) Am. J. Sci. 245, 401-20.CrossRefGoogle Scholar
Robins, B., and Tysseland, M. (1983) Chem. Geol. 40, 69-95.CrossRefGoogle Scholar
Rubie, D.C., and Gunter, W.D. (1983) Contrib. Mineral. Petrol. 82, 165-75.CrossRefGoogle Scholar
Shah, S.M.I., Siddiqui, R.A., and Talent, J.A. (1980) Rec. geol. Surv. Pakistan, 44, 1-31.Google Scholar
Speer, J.A. (1984) In Micas (Bailey, S.W., ed.). Reviews in Mineralog. 13, Min. Soc. Am. 299348.Google Scholar
Stumm, W., and Morgan, J.J. (1970) Aquatic chemistry. Wiley-Interscience. New York.Google Scholar
Vartiainen, H. (1980) Geol. Surv. Finland, Bull.313.Google Scholar
Vartiainen, H. and Woolley, A.R. (1976) Ibid. 280.Google Scholar
Verwoerd, W.J. (1966) Fenitization of Basic Rocks. In Carbonatites (O. F. Tuttle and J. Gittins, eds.). 295 308, Wiley, London.Google Scholar