Uranium-rich Granites in the Olden Window, Sweden

Björn Troëng
Geological Survey of Sweden, Box 801, S-951 28 Luleå, Sweden

Abstract: U-enriched granites occur in a Precambrian window in the Caledonides of central Sweden and intrude an extensive supracrustal formation dominated by acid terrestrial volcanics. During the Caledonian orogeny, thrusting, foliation, mylonites, and mesoscopic folds developed in the Precambrian rocks under low-grade metamorphic conditions. Ground and airborne γ-spectrometry indicate U-enrichment mainly in the northern part of the window where two uraniferous granites have been intruded. Several small U vein-type mineralizations are associated with one of the granites. The largest occurrence of the mineralization might be economic, and a Rb-Sr age determination has established a minimum age of 1500 Ma on the associated granite which is highly evolved.

Mineralogical Magazine; June 1982 v. 46; no. 339; p. 217-226; DOI: 10.1180/minmag.1982.046.339.08
© 1982, The Mineralogical Society
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