Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-02T18:59:40.419Z Has data issue: false hasContentIssue false

Chemical variation of clinopyroxene phenocrysts from the trachybasaltic lavas of Mount Etna, Sicily

Published online by Cambridge University Press:  05 July 2018

A. M. Duncan
Affiliation:
Geology Section, Department of Science, Luton College of Higher Education, Luton LU1 3JU
R. M. F. Preston
Affiliation:
Department of Geology, University College London, Gower Street, London WC1E 6BT

Summary

The chemical variation of clinopyroxene phenocrysts from the trachybasaltic lavas of Etna volcano is described. The phenocrysts show a limited, but distinct trend in chemical variation from calcic-augite in the hawaiites to augite in the benmoreites. The trend of this variation is unusual, being one of Mg-enrichment with differentiation of the magma. Ca shows a steady decrease in the clinopyroxenes from the hawaiites to the benmoreites. Na, however, shows little chemical variation in the pyroxenes. The trace element chemistry is briefly examined. The clinopyroxenes show well-developed oscillatory and sector zoning. The basal {11} sectors are enriched in Si and Mg and depleted in Ti, Al, and Fe relative to the {100}, {110}, and {010} prism sectors.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1980

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

Augustithus, (S. S.), 1976. In International congress on thermal waters, geothermal energy and vulcanism of the Mediterranean area. 3. Proceedings on vulcanism, pp. 1-11.Google Scholar
Bottinga, (Y.), Kudo, (A.), and Weill, (D.), 1966. Am. Mineral. 51, 792-806.Google Scholar
Burns, (R. G.), 1970. Mineralogical applications of crystal field theory. Cambridge, Cambridge University Press.Google Scholar
Campbell, (I. H.) and Borley, (G. D.), 1974. Contrib. Mineral. Petrol. 47, 281-97.CrossRefGoogle Scholar
Carmichael, (I. S. E.), Turner, (F. J.), and Verhoogen, (J.), 1974. Igneous Petrology. New York, McGraw-Hill.Google Scholar
Curtis, (C. D.), 1964. Geochim. Cosmochim. Acta. 28, 389-4°3.CrossRefGoogle Scholar
Deer, (W. A.), Howie, (R. A.), and Zussman, (J.), 1978. Rock-forming minerals. 2a. Single chain silicates. London, Longmans.Google Scholar
Downes, (M. J.), 1974. Contrib. Mineral. Petrol. 47, 187-96.CrossRefGoogle Scholar
Dowty, (E.), 1976. Am. Mineral. 61, 460-9.Google Scholar
Duncan, (A. M.), 1978. Geol. Mag. 115, 273-85.CrossRefGoogle Scholar
Fodor, (R. V.), Keil, (K.), and Bunch, (T. E.), 1975. Contrib. Mineral. Petrol, 50, 173-95.CrossRefGoogle Scholar
Harkins, (E.) and Hollister, (L. S.), 1977. Am. Mineral. 62, 390-4.Google Scholar
Henderson, (P.), 1979. Mineral. Mag. 43, 399-404.CrossRefGoogle Scholar
Hollister, (L. S.) and Gancarz, (A. J.), 1971. Am. Mineral. 56, 959-79.Google Scholar
Le Bas, (M. J.), 1962. Am. J. Sci. 260, 267-88.CrossRefGoogle Scholar
Leung, (I. S.), 1974. Am. Mineral. 59, 12738.Google Scholar
Nakamura, (Y.), 1973. Ibid., 58, 986-90.Google Scholar
Scott, (P. W.), 1976. Mineral. Mag. 40, 805-161.CrossRefGoogle Scholar
Strong, (D. F.), 1969. Ibid.. 37, 472-79.Google Scholar
Wass, (S. Y.), 1973. Ibid., 39, 133-44.Google Scholar