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Chemical variation in tourmalines from South-west England

Published online by Cambridge University Press:  14 March 2018

G. M. Power
G. M. Power*
Affiliation:
Department of Geology, University College of Wales, Aberystwyth
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Summary

Forty-eight samples of tourmaline from the granitic rocks of south-west England have been analysed by emission spectrography for Fe, Mn, Mg, Ca, Ti, Na, F, Li, Sc, V, Cr, Co, Ni, Cu, Ga, Rb, Sr, Zr, Sn, and Sc. The tourmaline reflects the fractionation trends of the rocks from which it comes in the proportion of Mg, Ca, Ti, and certain trace elements it contains and is considered likely to have been a primary product of the magma. Textural evidence that indicates a later development is interpreted as recrystallization, possibly at low temperature, with little change in chemical composition. Hydrothermal tourmaline has a distinctive chemical composition, being higher in Mg, Ca, Sr, and Sn and lower in Fe, Mn, and F and also tending to have a higher Cr, V, Ni, and Sc content. The chemical composition of the tourmalines is used to show that some quartz-tourmaline rocks are the product of extreme fractionation and are not completely tourmalinized granites. Parti-coloured tourmaline is shown to be the result of hydrothermal growth.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 36 , Issue 284 , December 1968 , pp. 1078 - 1089
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1968

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References

Brammall, (A.) and Harwood, (H. F.), 1925. Tourmalinization in the Dartmoor granite. Min. Mag., vol. 20, pp. 26–38.Google Scholar
Butler, (J. R.), 1953. The geochemistry and mineralogy of rock weatherings. (1) The Lizard area, Cornwall. Geochimica Acta, vol. 4, pp. 157–178 [M.A. 12-275].Google Scholar
Carobbi, (G.) and Pieruccnini, (R.), 1947. Spectrographic analyses of tourmalines from the island of Elba with correlation of color and composition. Amer. Min., vol. 32, pp. 121–130.Google Scholar
Exley, (C. S.) and Stone, (M.), 1964. The granitic rocks of south west England. In Present views on some aspects of the geology of Cornwall and Devon (Hosking, (K. F. G.) and Shrimpton, (G. J.), editors), pp. 132–184. Truro (Roy. Geol. Soc. Cornwall) [M.A. 17-650].Google Scholar
Flett, (J. S.), 1909. In Ussher, (W. A. E.), Barrow, (G.), and MacAlister, (D. A.), The geology of the country around Bodmin and St. Austell. Mem. geol. Surv. U.K.Google Scholar
Frondel, (C.) and Collette, (R. L.), 1957. Synthesis of tourmaline by reaction of mineral grains with NaCl-H3BO3 a solution and its implications in rock metamorphism. Amer. Min., vol. 42, pp. 754–758 [M.A. 13-640].Google Scholar
Hatch, (F. H.), Wells, (A. K.), and Wells, (M. K.), 1949. The petrology of the Igneous rocks. London (T. Murby).Google Scholar
Krynine, (P. D.), 1946. The tourmaline group in sediments. Journ. Geol., vol. 54, pp. 65–87.Google Scholar
Power, (G. M.), 1966. Strontium ; calcium ratio in tourmalines from South-west England. Nature, vol. 211, pp. 1072–1073 [M.A. 18-275].CrossRefGoogle Scholar
Smith, (F. G.), 1949. Transport and deposition of the non-sulphide vein minerals. IV. Tourmaline. Econ. Geol., vol. 44, pp. 186–192.CrossRefGoogle Scholar
Staatz, (M. H.), Murata, (K. J.), and Glass, (J. J.), 1955. Variation of composition and physical properties of tourmaline with its position in the pegmatite. Amer. Min., vol. 40, pp. 789–804 [M.A. 13-203].Google Scholar
Tennant, (C. B.) and White, (M. L.), 1959. A study of the distribution of some geochemical data. Econ. Geol., vol. 54, pp. 1281–1290.Google Scholar
Warner, (T. W.), 1935. Spectrographic analyses of tourmaline with correlation of color and composition. Amer. Min., vol. 20, pp. 531–536.Google Scholar
Wells, (M. K.), 1946. A contribution to the study of luxullianite. Min. Mag., vol. 27, pp. 186–194.Google Scholar