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Feldspar relations in Icelandic alkalic rhyolites

Published online by Cambridge University Press:  05 July 2018

Haraldur Sigurdsson
Haraldur Sigurdsson*
Affiliation:
Dept. of Geology, The University of Durham1
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Summary

Alkalic rhyolites with peralkaline affinities, bearing quartz and potassic feldspar phenocrysts, are described from Iceland for the first time. Evidence from electron-probe analyses of feldspar phenocrysts indicates crystallization in or near the thermal valley of the system SiO2-Or-Ab. Icelandic acid volcanic rocks are subdivided into alkalic rhyolites, belonging to transitional and alkalic basalt lineages, and the mildly calc-alkaline rhyolites of tholeiite lineages.

Type
Research Article
Information
Mineralogical Magazine , Volume 38 , Issue 296 , December 1971 , pp. 503 - 510
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1971

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Footnotes

1

Present address: Seismic Research Unit, University of the West Indies, St. Augustine, Trinidad.

References

Carmichael, (I. S. E.), 1962. A note on the composition of some natural acid glasses. Geol. Mag. 99, 253.Google Scholar
Carmichael, (I. S. E.), 1963. Crystallization of feldspar in volcanic acid liquids. Quart. Journ. Geol. Soc. 119, 95.Google Scholar
Carmichael, (I. S. E.), 1967. The iron-titanium oxides of salic volcanic rocks and their associated ferromagnesian silicates. Contr. Min. Petr. 14, 36.Google Scholar
Carmichael, (I. S. E.), and Mackenzie, (W.S.), 1963. Feldspar-liquid equilibria in pantellerites: an experimental study. Amer. Journ. Sci. 261, 382.Google Scholar
Macdonald, (G.A.), 1944. Petrography of the Samoan Islands. Bull. Geol. Soc. Amer. 55, 1333.CrossRefGoogle Scholar
Nockolds, (S.R.), 1954. Average chemical compositions of some igneous rocks. Ibid. 65, 1007.Google Scholar
Richards, (H.C.), 1916. The volcanic rocks of south-eastern Queensland. Proc. Roy. Soc. Queensland, 27, 105.Google Scholar
Thompson, (R.N.) and Mackenzie, (W.S.), 1967. Feldspar-liquid equilibria in peralkaline acid liquids: an experimental study. Amer. Journ. Sci. 265, 714.CrossRefGoogle Scholar
Tuttle, (O.F.) and Bowen, (N.L.), 1958. Origin of granite in the light of experimental studies in the system NaAlSi3O8-KAlSi3O8-SiO2-H2O. Geol. Soc. Amer. Meg. 74.Google Scholar
Walker, (G. P. L.), 1966. Acid volcanic rocks in Iceland. Bull. Volc. 29, 375.Google Scholar
Wilkinson, (J, F. G.), 1968. The magmatic affinities of some volcanic rocks from the Tweed Shield Volcano, S.E. Queensland-N.E. New South Wales. Geol. Mag. 105, 275.Google Scholar