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Petrology of alkali wehrlite sills in the Oman Mountains

Published online by Cambridge University Press:  05 July 2018

S. J. Lippard
S. J. Lippard*
Affiliation:
Earth Science Department, Open University, Milton Keynes, MK7 6AA, UK
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Abstract

Alkaline mafic sills of Jurassic to Cretaceous age in the Oman Mountains have coarse-grained wehrlite centres composed of olivine and zoned diopside-titanaugite with large interstitial poikilitic titanian hornblendes and titanian barian phlogopites and biotites which appear to have crystallized from a trapped, intergranular, volatile-rich liquid. The fine-grained chilled margins of the sills are olivine-poor and composed largely of titanaugite, kaersutite, sphene, and interstitial altered plagioclase. The rocks have high contents of incompatible elements (Ti, P, Sr, Ba, Zr, Nb, and others) and steeply inclined, light element enriched, REE patterns. The parent magma is estimated to have been a hydrous alkali picrite with c. 12% MgO from which the wehrlite formed by olivine accumulation. The unusual tectonic setting of the sills, in a Mesozoic continental margin sequence emplaced in an Alpine thrust belt, is noted.

Type
Research Article
Information
Mineralogical Magazine , Volume 48 , Issue 346 , March 1984 , pp. 13 - 20
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

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References

Bailey, D. K. (1980) Phil. Trans. R. Soc. Lond. A297, 309–22.Google Scholar
Bhattacharji, S., and Smith, C. H. (1964) Science. 140, 150–3.CrossRefGoogle Scholar
Glennie, K. W., Boeuf, M, Hughes Clark, M. W., Moody-Stuart, M., Pilaar, W. F. H., and Reinhardt, B. M. (1974) Verh. K. Ned. geol-mijnbouw, Genoot. Part 1 (text), 1–423.Google Scholar
Graham, G. M. (1980) Ph.D. thesis, Open University (unpubl.).Google Scholar
Green, D. H., and Ringwood, A. E. (1967) Contrib. Mineral. Petrol. 15, 103–90.CrossRefGoogle Scholar
Harris, P. G. (1957) Geochem. Cosmochem. Ada. 12, 195–208.CrossRefGoogle Scholar
Kesson, S. E., and Price, R. C. (1972) Contrib. Mineral. Petrol. 35, 119–24.CrossRefGoogle Scholar
Leake, B. E. (1978) Mineral. Mag. 42, 533–63.CrossRefGoogle Scholar
LeBas, M. J. (1962) Am. J. Sci. 260, 267–88.CrossRefGoogle Scholar
Lippard, S. J., and Rex, D. C. (1982) Geol. Mag. 119, 497–503.CrossRefGoogle Scholar
Lloyd, F. E., and Bailey, D. K. (1975) Phys. Chem. Earth. 9, 389–416.CrossRefGoogle Scholar
Mysen, B. O., and Boettcher, A. L. (1975) J. Petrol. 16, 520–48.CrossRefGoogle Scholar
Nakamura, N. (1974) Geochem. Cosmochem. Ada. 38, 757–75.CrossRefGoogle Scholar
Nixon, P. H., Mitchell, R. H., and Rogers, N. W. (1980) Mineral. Mag. 43, 587–96.CrossRefGoogle Scholar
O'Hara, M. J. (1965) Scott. J. Geol. 1, 19–40.CrossRefGoogle Scholar
Potts, P. J., Thorpe, O. W., and Watson, J. S. (1981) Chem. Geol 34, 331–52.CrossRefGoogle Scholar
Robins, B. (1974) Nor. geol. Tidsskr. 54, 247–68.Google Scholar
Rock, N. M. S. (1977) Earth Sci. Rev. 13, 123–69.CrossRefGoogle Scholar
Roeder, P. L., and Emslie, R. F. (1970) Contrib. Mineral. Petrol. 29, 275–89.CrossRefGoogle Scholar
Scott, P. W. (1976) Mineral. Mag. 40, 805–16.CrossRefGoogle Scholar
Searle, M. P., and Graham, G. M. (1982) Geology. 10, 43–9.2.0.CO;2>CrossRefGoogle Scholar
Searle, M. P. and Malpas, J. (1980) Trans. R. Soc. Edinburgh Earth Sci. 71, 247–62.CrossRefGoogle Scholar
Searle, M. P., Lippard, S. J., Smewing, J. D., and Rex, D. C. (1980) J. geol. Soc. Lond. 137, 589–604.CrossRefGoogle Scholar
Wedepohl, K. H., and Muramatsu, Y. (1979) In Kimber-lites, Diatremes and Diamonds: their Geology, Petrology and Geochemistry (Boyd, F. R. and Meyer, H. O. A., eds.). Am. Geophys. Union, Washington, 300–12.CrossRefGoogle Scholar
Wendlandt, R. F. (1977) Carnegie Inst. Washington Yearb. 1976-7, 441–8.Google Scholar
Wyllie, P. J. (1977) J. geol. Soc. Lond. 134, 215–34.CrossRefGoogle Scholar