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Geochemistry of Greisenized Granites and Metasomatic Schist of Tungsten-Tin Deposits in Portugal

  • A. M. R. Neiva
Part of the NATO ASI Series book series (ASIC, volume 218)

Abstract

Greisenization of S-type granites from Panasqueira and Alijó (Portugal) are compared for both major and trace elements. Tungstentin mineralization is connected with the Panasqueira greisenized cupola while tin-tungsten mineralization is connected with the granite and greisenized granite from Alijó. During greisenization Sn, W, Nb, Ta, Zn, Pb, Rb increase whereas temperature decreases. If tin mineralization dominates, Sn is concentrated in cassiterite and the muscovite of the greisenized granite is depleted in Sn, but richer in W and F than the muscovite of the parental granite. If tungsten mineralization dominates, the muscovite of the greisenized granite has similar W, more Sn and less F than the muscovite of the parental granite. Wolframite is the main carrier of W. F is concentrated in topaz and fluorite.

The muscovite-ripidolite schist from Borralha (Portugal) was contact and metasomatically altered into a muscovite schist with some almandine-spessartine by fluids which originated tungsten quartz veins. Both schists were studied for major and trace elements. The metasomatism was accompanied by increase in W, Nb, Ta, Sn, Rb, Cs and decrease in temperature and log \( ({f_{{H_2}O}}/{f_{HF}}) \). The muscovite of the metasomatic schist is concentrated in F, W, Sn, Rb, Cs, while garnet is concentrated in Nb and Ta.

Keywords

Quartz Vein Metasomatic Alteration Bishop Tuff Tungsten Mineralization Parental Granite 
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Copyright information

© D. Reidel Publishing Company 1987

Authors and Affiliations

  • A. M. R. Neiva
    • 1
  1. 1.Department of Mineralogy and GeologyUniversity of CoimbraCoimbraPortugal

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