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Distribution of trace elements in feldspars of granitic aplites and pegmatites from Alijó-Sanfins, northern Portugal

Published online by Cambridge University Press:  05 July 2018

A. M. R. Neiva
A. M. R. Neiva*
Affiliation:
Department of Earth Sciences, University of Coimbra, 3000 Coimbra, Portugal
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Abstract

At Alijó-Sanfins there are many granitic aplite and pegmatite veins crosscutting different petrographic facies of the Hercynian granite batholith and also mica-schists. They are tin-bearing granitic rocks. Thirty-four samples of K-feldspar and 34 of albite from these veins and host granites were analysed to establish the distribution of elements and their fractionation trends in the sequence of feldspar crystallization. Rubidium and Cs increase, and Ba, Sr, Ba/K, Sr/K and K/Rb decrease in K-feldspar, whereas Na increases and Sr and Ca decrease in albite, from granites to aplites and pegmatites. In a few aplite-pegmatite veins Rb, Rb/Ba and Rb/Sr increase and Ba, Sr, K/Rb and Ba/Sr decrease in K-feldspar, and Rb increases and Sr decreases in albite from aplite to coexisting pegmatite. Equilibrium was not attained for trace elements between coexisting feldspars.

Keywords

K-feldsparalbitegranitic pegmatiteaplitetrace elements
Type
Mineralogy
Information
Mineralogical Magazine , Volume 59 , Issue 394 , March 1995 , pp. 35 - 45
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1995

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References

Arth, J. G. (1976) Behaviour of trace elements during magmatic processes: A summary of the theoretical models and their applications. J. Res. USGS, 4, 41–7.Google Scholar
ferny, P., Smith, J. V., Mason, R. A. Delay, J. S. (1984) Geochemistry and petrology of feldspar crystallization in the VSZna pegmatite, Czechoslovakia. Can. Mineral., 22, 631–51.Google Scholar
Cerny, P., Meintzer, R. E. and Anderson, A. J. (1985) Extreme fractionation in rare-element pegmatites: selected examples of data and mechanisms. Can. Mineral, 23, 381–421.Google Scholar
Christie, O. H. J., Falkum, T., Ramberg, I. B., Thorensen, K. (1970) Petrology of the Grimstad granite. II. Petrography, geochemistry, crystallography of alkali feldspars and genesis. Norges Geol. Unders0k, 265, 78 pp.Google Scholar
Corlett, N. and Ribbe, P. H. (1967) Electron microanalysis of minor elements in plagioclase feldspars. Schweiz, Miner. Petr. Mitt., 47, 317–32.Google Scholar
Iiyama, J. T. (1968) Etude experimentale de la distribution d'elements en traces entre deux feldspaths. Feldspath potassique et plagioclase coexistants. 1. Distribution de Rb, Cs, Sr et Ba a 600°C. Bull. Soc. fr. Mineral. Cristallogr., 91, 130–40.Google Scholar
Jolliff, B. L., Papike, J. J. and Shearer, C. K. (1992) Petrogenetic relationships between pegmatite and granite based on geochemistry of muscovite in pegmatite wall zones, Black Hills, South Dakota, USA. Geochim. Cosmochim. Ada, 56, 1915–40.CrossRefGoogle Scholar
Neiva, A. M. R. (1973) Geochemistry of the granites and their minerals from the central area of northern Portugal. Mem. Not. Mus. Lab. Mineral. Geol. Univ. Coimbra, 76, 1–43.Google Scholar
Neiva, A. M. R. (1974a) Optical axial angle and obliquity of potassium feldspars of granites, aplites and pegmatites. In The Feldspars, W. S. Mackenzie and J. Zussman (eds.), Proceedings of a NATO Advanced Study Institute, Manchester University Press, Great Britain, 610-4.Google Scholar
Neiva, A. M. R. (1974b) Geochemistry of the aplites and their minerals of central northern Portugal. Cotnun. Serv. Geol. Portugal, LVIH, 211-37.Google Scholar
Neiva, A. M. R. (1975) Geochemistry of coexisting aplites and pegmatites and their minerals from central northern Portugal. Chem. Geol., 16, 153–77.CrossRefGoogle Scholar
Neiva, A. M. R. (1977) Geochemistry of the pegmatites and their minerals from central northern Portugal. Anais Fac. Cienc. Porto, LX, 1-28.Google Scholar
Neiva, A. M. R. (1984). Geochemistry of tin-bearing granitic rocks. Chem. Geol., 43, 241–56.CrossRefGoogle Scholar
Shearer, C. K., Papike, J. J. and Laul, J. C. (1985) Chemistry of potassium feldspars from three zoned pegmatites, Black Hills, South Dakota: implications concerning pegmatite evolution. Geochim. Cosmochim. Ada, 49, 663–74.CrossRefGoogle Scholar
Shearer, C. K., Papike, J. J. and Jolliff, B. L. (1992) Petrogenetic links among granites and pegmatites in the Harney Peak rare-element granite-pegmatite system, Black Hills, South Dakota. Can. Mineral, 30, 785–810.Google Scholar
Smeds, S. A. (1992) Trace elements in potassium-feldspar and muscovite as a guide in the prospecting for lithium-and tin-bearing pegmatites in Sweden. J. Geochem. Exploration, 42, 351–69.CrossRefGoogle Scholar
Smith, J. V. (1974) Feldspar Minerals. 2, Chemical and textural properties. Springer-Verlag, New York.Google Scholar
Smith, J. V. (1975) Some chemical properties of feldspars. In Feldspar Mineralogy, Ribbe, P. H. (ed.), Mineralogical Society of America. Short course notes, 2, Sm 18-29.Google Scholar
Smith, J. V. and Brown, W. (1988) Feldspar Minerals. 1. Crystal structures, physical, chemical and micro-textural properties. Second revised and extended edition. Springer-Verlag, New York.Google Scholar
Taylor, S. R. and Heier, K. S. (1960) The petrological significance of trace element variation in alkali feldspars. Rept. 21st Intern. Geol. Congress, Norden, 14, 47–61.Google Scholar
Trueman, D. L. and Cen, P. (1982) Exploration for rare-element granitic pegmatites. In Short course in granitic pegmatites in science and industry, Cem, P. (ed.), Mineralogical Association of Canada, 463-94.Google Scholar