Hostname: page-component-7479d7b7d-t6hkb Total loading time: 0 Render date: 2024-07-13T21:12:15.213Z Has data issue: false hasContentIssue false
  • English
  • Français

An occurrence of rare-earth-rich eudialyte from Ascension Island, South Atlantic

Published online by Cambridge University Press:  05 July 2018

C. Harris ,
G. Cressey ,
J. D. Bell ,
F. B. Atkins  and
S. Beswetherick
C. Harris
Affiliation:
Department of Geology and Mineralogy, Parks Road, Oxford
G. Cressey
Affiliation:
Department of Geology and Mineralogy, Parks Road, Oxford
J. D. Bell
Affiliation:
Department of Geology and Mineralogy, Parks Road, Oxford
F. B. Atkins
Affiliation:
Department of Geology and Mineralogy, Parks Road, Oxford
S. Beswetherick
Affiliation:
Department of Geology and Mineralogy, Parks Road, Oxford
Get access Rights & Permissions [Opens in a new window]

Abstract

A mineral closely resembling eudialyte in single crystal X-ray pattern and chemistry has been found in one granite block from the 5 Mile Post area on Ascension Island. To our knowledge, eudialyte has not previously been recognized in this suite of granites although they contain two other rare zirconium silicates, dalyite and vlasovite. Textural evidence suggests that the eudialyte, which is remarkable for its high yttrium and REE content, crystallized from very late-stage magmatic fluids. Rare-earth patterns are only slightly fractionated (CeN/YN = 1.8–2.5) compared with those of allanites and sphenes from Skye granites which presumably have similar parageneses. In contrast, the whole-rock REE pattern shows greater enrichment of light REE (CeN/YN ∼ 10). This difference in REE pattern is considered to be due to the effects of REE and other element complexing related to the peralkalinity of the granite liquid.

Type
Research Article
Information
Mineralogical Magazine , Volume 46 , Issue 341 , December 1982 , pp. 421 - 425
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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

Dickin, A. P., and Exley, R. A. (1981) Contrib. Mineral. Petrol. 76, 98–108.CrossRefGoogle Scholar
Drake, M. J., and Weill, D. F. (1972) Chem. Geol. 10, 179–81.CrossRefGoogle Scholar
Eby, G. N. (1975) Geochim. Cosmochim. Acta. 39, 597–620.CrossRefGoogle Scholar
Edgar, A. D., and Blackburn, C. E. (1972) Can. Mineral. 11, 554–9.Google Scholar
Exley, R. A. (1980) Earth Planet. Sci. Lett. 48, 97–110.CrossRefGoogle Scholar
Fleet, S. G., and Cann, J. R. (1967) Mineral. Mag. 36, 233–41.Google Scholar
Frey, F. A., Haskin, M. A., Poetz, J. A., and Haskin, L. A. (1968) J. Geophys. Res. 73, 60–85.CrossRefGoogle Scholar
Fryer, B. J., and Edgar, A. D. (1977) Contrib. Mineral. Petrol. 61, 35–48.CrossRefGoogle Scholar
Gossner, B. (1930) Centralbl. Mineral. A, 449–50.Google Scholar
Hey, M. H. (1962) Chemical Index of Minerals, 2nd edn. The British Museum (Natural History), London.Google Scholar
Nakamura, N. (1974) Geochim. Cosmochim. Acta, 38, 757.CrossRefGoogle Scholar
Roedder, E., and Coombs, D. S. (1967) J. Petrol. 8, 417–51.CrossRefGoogle Scholar
van Tassel, R. (1952) Mineral. Mag. 29, 850–7.Google Scholar