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The iron content and optic axial angle in zoisites from Galicia, NW Spain

Published online by Cambridge University Press:  05 July 2018

P. Maaskant
P. Maaskant*
Affiliation:
Instituut voor Aardwetenschappen, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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Abstract

Electron probe microanalyses of zoisites from high-grade metamorphic rocks in Galicia, NW Spain have been obtained. The elements Na, Mg, P, K, Ti, and Mn were not detected above the 0.1 wt. % level. Assuming all Fe is present as Fe3+, a clear relation is obtained between the Fe content and the optic axial angle. Zoisite with 1.6 wt. % Fe2O3 proves to be uniaxial at 589 nm; uniaxiality in blue light (470 nm) lies at 1.5 wt. % Fe2O3. A change of the optic sign, from positive to negative, is obtained at 2.9 wt. % Fe2O3. The presence of minor elements greatly affects this relation, as is indicated by analyses of sector-zoned Sr-bearing zoisites of a muscovite-zoisite pegmatite from the same region. Under retrograde conditions Fe-rich α-zoisite reacts to form less Fe-rich α-zoisite or β-zoisite and clinozoisite.

Keywords

zoisitemetamorphismoptic axial angleironGaliciaSpain
Type
Research Article
Information
Mineralogical Magazine , Volume 49 , Issue 350 , March 1985 , pp. 97 - 100
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1985 

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References

Ackermand, D., and Raase, P. (1973) Contrib. Mineral. Petrol. 42, 333-41.Google Scholar
Banno, S. (1964) J. Fac. Sci. Univ. Tokyo, sec. II, 15, 203-19.Google Scholar
Battey, M. H. (1975) Mineralogy for students. Longman Group Ltd., London, 323 pp.Google Scholar
Deer, W. A., Howie, R. A., and Zussman, J. (1967) An introduction to the rock-forming minerals. Longmans, Green & Co., London, 528 pp.Google Scholar
Enami, M., and Banno, S. (1977) J. Geol. Soc. Japan 83, 737-9.Google Scholar
Enami, M. (1980) Mineral. Mag. 43, 1005-13.Google Scholar
Hietanen, A. (1974) Am. Mineral. 59, 22–40.Google Scholar
Ii, N., and Shindo, I. (1979) J. Cryst. Growth, 46, 569-74.Google Scholar
Myer, G. H. (1966) Am. J. Sci. 264, 364-85.Google Scholar
Phillips, W. M., and Griffen, D. T. (1981) Optical Mineralogy. The Nonopaque Minerals. Freeman & Co., San Francisco, 677 pp.Google Scholar
Raith, M. (1976) Contrib. Mineral. Petrol. 57, 99-117.Google Scholar
Richter, W. (1973) Tschermak's Mineral. Petr. Mitt. 19, 1-50.Google Scholar
Saggerson, E. P. (1975) Identification tables for minerals in thin sections. Longman Group Ltd., London, 378 pp.Google Scholar
Sweatman, T. R., and Long, J. V. P. (1969) J. Petrol. 10, 332-79.Google Scholar
Termier, P. (1898) Soc.fran#aise mineral. Bull. 21, 148-70.Google Scholar
Termier, P. (1900) Ibid. 23, 50-64.Google Scholar
Tröger, W. E. (1982) Optische Bestimmung der gesteins-bildenden Minerale. Tell 1. BestimmungstabeUen. Stuttgart, E. Schweizerbart'sche Verlagsbuchhandlung, 188 pp.Google Scholar
Vogel, D. E. (1967) Leidse Geol. Mededel. 40, 121-213.Google Scholar
Vogel, D. E. and Bahezre, C. (1655) Neues Jahrb. Mineral. Monatsh. 1409.Google Scholar
Winchell, A. N. and Winchell, H. (1959) Elements of optical mineralogy. Part II. Description of minerals. John Wiley & Sons, Inc., New York, 551 pp.Google Scholar