Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-29T07:35:42.103Z Has data issue: false hasContentIssue false

The structures of the plagioclase felspars: III. An X-ray study of anorthites and bytownites

Published online by Cambridge University Press:  14 March 2018

P. Gay*
Affiliation:
Department of Mineralogy and Petrology; and Crystallographic Laboratory, Cavendish Laboratory, University of Cambridge

Extract

In a recent paper, Cole, Sörum, and Taylor described X-ray measurements on a number of plagioelases with compositions ranging from pure albite to pure anorthite. As a result, they were able to make more precise, and extend, the structural interpretations proposed on the basis of earlier X-ray investigations of the three typestructures, albite, anorthite, and intermediate plagioclases (Taylor, Darbyshire, and Strunz; Chao and Taylor). At the same time, new complexities were revealed which called for more detailed examination, among them the fact that the anorthite-type structure, with c-axis ∼14 Å., may have either a body-centred or a primitive unit cell. The body-centred cell was observed with a material containing 71.5% anorthite, the primitive cell with a nearly pure anorthite, but there was not sufficient evidence to show whether the difference was due entirely or largely to the difference in chemical composition, nor was a detailed investigation made of the effects of heat-treatments.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1953

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

Page 169 Note 1 Cole, W. F., Sörum, H., and Taylor, W. H., Acta Cryst., 1951, vol. 4, p. 20.CrossRefGoogle Scholar [M.A. 11-427.]

Page 169 Note 2 Taylor, W. H., Darbyshire, J. A., and Strunz, H., Zeits. Krist., 1934, vol. 87, p. 464.Google Scholar [M.A. 6-177.]

Page 169 Note 3 Chao, S. H. and Taylor, W. H., Proc. Roy. Soc. London, Ser. A, 1940, vol. 176, p. 76.CrossRefGoogle Scholar [M.A. 8-13.]

Page 170 Note 1 Köhler, A., Journ. Geol., 1949, vol. 57, p. 592.CrossRefGoogle Scholar [M.A. 11-144.]

Page 170 Note 2 Tertsch, H., Tschermaks, Min. Petr. Mitt., 1941, vol. 53, p. 50.Google Scholar [M.A. 8-313.]

Page 170 Note 3 van der Kaaden, G., Thesis,. Univ. Utrecht, 1951.Google Scholar [M.A. 11-282.]

Page 170 Note 4 Reynolds, D. L., Geol. Mag., 1952, vol. 89, p. 233.CrossRefGoogle Scholar [N[.A. 12-137.]

Page 174 Note 1 Some of these deductions are in accordance with results reported briefly by F. Laves and J. R. Goldsmith, in abstracts of papers to Amer. Cryst. Assoc. meeting, Chicago, 1951.

Page 175 Note 1 Chaisson, U., Journ. Geol., 1950, vol. 58, p. 537.CrossRefGoogle Scholar [5~.A. :11-326.]