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Rare earth element, Sr- and Nd-isotope evidence for petrogenesis of Permian basaltic and K-rich volcanic rocks from south-west England

Published online by Cambridge University Press:  05 July 2018

R. S. Thorpe ,
M. E. Cosgrove  and
P. W. C. van Calsteren
R. S. Thorpe
Affiliation:
Department of Earth Sciences, the Open University, Milton Keynes, MK7 6AA, UK
M. E. Cosgrove
Affiliation:
Department of Geology, the University, Highfield, Southampton, SO5 9NH, UK
P. W. C. van Calsteren
Affiliation:
Department of Earth Sciences, the Open University, Milton Keynes, MK7 6AA, UK
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Abstract

Permian basic/ultrabasic lavas from south-west England may be divided into a ‘basaltic’ and a K-rich group. Both groups have enrichment of large-ion lithophile (LIL) elements relative to high field strength (HFS) elements, and the K-rich group show large degrees of LIL enrichment (c.50–500 times primordial mantle) in association with varied transition element concentrations. Samples from both groups 87Sr/86Sri = 0.704–0.705 and 143Nd/144Ndi = 0.5123–0.5127 and plot close to the mantle array on an ɛSr−ɛNd diagram. These data are interpreted in terms of derivation of the lavas from magmas resulting from partial melting of mantle which had experienced less (for the basaltic group) or more (for the K-rich group) enrichment in LIL elements as a result of migration of mantle melts. Such enrichment accompanied or followed subduction of oceanic lithosphere below south-west England. The resultant magmas experienced fractional crystallization of olivine and pyroxene prior to eruption.

Keywords

rare earth elementsstrontium isotopesneodymium isotopesPermian lavassouth-west England
Type
Petrology
Information
Mineralogical Magazine , Volume 50 , Issue 357 , September 1986 , pp. 481 - 489
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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References

Badham, J.P.N., and Halls, C. (1975) Geology.3, 373.6.2.0.CO;2>CrossRefGoogle Scholar
Bailey, J.C. (1981) Chem. Geol. 32, 139-54.CrossRefGoogle Scholar
Cosgrove, M.E. (1972) Contr. Mineral. Petrol. 36, 155-70.CrossRefGoogle Scholar
Darbyshire, D.P.F., and Shepherd, T.J. (1986) J. geol. Soc. Lord. 142, 1159-77.CrossRefGoogle Scholar
Edmonds, E.A., McKeown, M.C. and Williams, M. (1969) British Regional Geology: Southwest Englan. 3rd edn., HMSO, London.Google Scholar
Exley, C.S., Stone, M., and Floyd, P.A. (1983) In The Variscan Fold Belt of the British Isle.(ed. P. L.Hancock). Adam Hilger Ltd., Bristol, pp. 153-77.Google Scholar
Floyd, P.A., Exley, C.S. and Stone, M. (1983) In The Variscan Fold Belt of the British Isle.(ed. P. L. Hancock). Adam Hilger Ltd., Bristol, pp. 178-85.Google Scholar
Hampton, C.M., and Taylor, P.N. (1983) J. geol. Soc. Lond. 140, 499-509.CrossRefGoogle Scholar
Hancock, P.L. (1983) The Variscanfold belt of the British Isle. Adam Hilger Ltd., Bristol, 217 pp.Google Scholar
Hawkes, J.R. (1981) Proc. Ussher So. 5, 128-31.Google Scholar
Hawkesworth, C.J., Rogers, N.W., van Calsteren, P.W.C. and Menzies, M.A. (1984) Nature. 311, 331-5.CrossRefGoogle Scholar
Hellman, P.L., Smith, R.E., and Henderson, P. (1979) Contr. Mineral. Petrol. 71, 23-44.CrossRefGoogle Scholar
Kay, R.W. and Gast, P.W. (1973) J. Geol. 81, 653-82.CrossRefGoogle Scholar
Knill, D.C. (1969) Bull. Geol. Sun. G.B. 29, 115-38.Google Scholar
Knill, D.C. (1982) In Igneous Rocks of the British Isle.(ed. D. S. Sutherland). John Wiley and Sons, Chichester, pp. 329-32.Google Scholar
McCulloch, M.T., Jaques, A.L., Nelson, D.R., and Lewis, J.D. (1983) Nature. 302, 400-3.CrossRefGoogle Scholar
Macdonald, R., Thorpe, R.S., Gaskarth, J.W., and Grindrod, A.R. (1985) Mineral. Mag. 49, 485-94.CrossRefGoogle Scholar
Miller, J.A., Shibata, K., and Munro, M. (1961) Geophys.J.6, 394-6.CrossRefGoogle Scholar
Pearce, J.A. (1982) In Andesites: Orogenic andesites and related rock.(ed. R. S. Thorpe). John Wiley and Sons, Chichester, pp. 525–548.Google Scholar
Pearce, J.A. (1983) In Continental basalts and mantle xenolith.(eds. C. J. Hawkesworth and M. J. Norry). Shiva Press, Nantwich, pp. 230-49.Google Scholar
Potts, P.J., Thorpe, O.W., and Watson, J.S. (1983) Chem. Geol. 34, 331-52.CrossRefGoogle Scholar
Rock, N.M.S. (1984) Trans. R. Soc. Edinburgh: Earth Sciences. 74, 193-227.CrossRefGoogle Scholar
Shimizu, N., and Arculus, R.J. (1975) Contr. Mineral. Petrol. 50, 231-40.CrossRefGoogle Scholar
Steiger, R.H., and Jager, E. (1977) Set Lett. 36, 359-62.Google Scholar
Sun, S.S., and Hanson, G.M. (1975) Geology. 3, 297. 302.2.0.CO;2>CrossRefGoogle Scholar
Thompson, R.N., Morrison, M.A., Hendry, G.L., and Parry, S.J. (1984) Phil. Trans. R. Soc. Lon. A310, 549-90.Google Scholar
Thorpe, R.S., Beckinsale, R.D., Patchett, P.J., Piper, J.D.A., Davies, G.R., and Evans, J.A. (1984) J. geol. Soc. Lond. 141, 521-36.CrossRefGoogle Scholar
Velde, D. (1971) Geol. Mag. 108, 201-4.CrossRefGoogle Scholar
Venturelli, G., Thorpe, R.S., Dal Piaz, G.V., Del Moro, A., and Potts, P.J. (1984) Contr. Mineral. Petrol. 86, 209-20.CrossRefGoogle Scholar
Whittaker, A. (1974) Proc. Ussher Soc. 3, 95.Google Scholar
Wood, D.A. (1979) Geology. 7, 499-503.2.0.CO;2>CrossRefGoogle Scholar
Wood, D.A., Joron, J.L., and Treuil, M. (1979) Earth Planet. Sci. Lett. 45, 326-36.CrossRefGoogle Scholar