Hostname: page-component-7479d7b7d-fwgfc Total loading time: 0 Render date: 2024-07-11T23:52:10.502Z Has data issue: false hasContentIssue false
  • English
  • Français

Synmetamorphic uranium mineralization from Tiraun, Graubünden, Switzerland

Published online by Cambridge University Press:  05 July 2018

E. von Pechmann  and
F. Bianconi
E. von Pechmann
Affiliation:
Uranerzbergbau-GmbH, Kölnstr. 367, D-5300 Bonn 1, Germany
F. Bianconi
Affiliation:
Uranerzbergbau-GmbH, Kölnstr. 367, D-5300 Bonn 1, Germany
Get access Rights & Permissions [Opens in a new window]

Abstract

Petrographic, microscopic, and X-ray investigations of a uranium occurrence near Tiraun, Graubünden, Switzerland, are described. The uranium mineralization occurs in greenschist facies metamorphic rocks of the Tavetsch massif and consists essentially of uraninite of various habits with minor chalcopyrite, linnaeite, millerite, galena, marcasite, pyrite, hematite, magnetite, and skutterudite. The ore structure, characterized by concentrations along foliation planes, boudinage, and rotated (helicitic) textures of uraninite porphyroblasts, is indicative of a synmetamorphic (Alpine) remobilization, recrystallization and enrichment of the ore, which was probably derived from an original ‘protore’ in psephites and psammites (? sandstone-type mineralization) of at least Variscan age. The synmetamorphic emplacement of the ore took place under medium- to high-temperature conditions (approx. 350–400°C), as demonstrated by the lattice constants of the uraninite phases and by the ore paragenesis. Late to postmetamorphic tectonism resulted in a partial remobilization (over cm distances) and redistribution of the ore along veinlets that cut the foliation planes. The characteristics of the ore from Tiraun are similar to those from the synmetamorphic ore from Preit, northern Italy, as described by Cevales (1961).

Type
Research Article
Information
Mineralogical Magazine , Volume 46 , Issue 339 , June 1982 , pp. 173 - 178
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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

Brooker, E. J., and Nuffield, E. W. (1952 Am. Mineral. 37, 363-85.Google Scholar
Cathelineau, M., Cuney, M., Leroy, J., Lhote, F., Nguyen Trung, C, Pagel, M., and Poty, B. (1979 Paper presented at the Technical Committee Meeting on the geology of vein and similar type uranium deposits (IAEA), Lisbon, 17 pp.Google Scholar
Cevales, G. (1961 Neues Jahrb. Mineral. Abh. 96, 112-23.Google Scholar
Frey, M., Trommsdorff, V., and Wenk, E. (1980 In Geology of Switzerland, Part B: Geological Excursions. Schweiz. Geol. Komm., Wepf & Co., Basel, New York, 334 pp.Google Scholar
Klemm, D. D. (1962 Neues Jahrb. Mineral. Abh. 97, 337-56.Google Scholar
Kramers, J. D. (1973 Beitr. Geol. Schweiz, Geotechn. Ser. 52, 75 pp.Google Scholar
Makarov, E. S., Lipova, I. M., Dolmanova, I. F., and Melikyan, A. A. (1960 Geochim. 193-213.Google Scholar
Niggli, E. (1967 In Geologischer Führer der Schweiz. Schweiz. Geol. Ges., Wepf & Co., Basel.Google Scholar
Ramdohr, P. (1953 Geol. Rdsch. 42, 11-19CrossRefGoogle Scholar
Ramdohr, P. (1975 Die Erzmineralien und ihre Verwachsungen, 4th edn. Akademie-Verlag, Berlin, 1277 pp.Google Scholar
Spry, A. (1974 Metamorphic Textures. Pergamon Press, 350 pp.Google Scholar
Voultsidis, V., von Pechmann, E., and Clasen, D. (1982 In Amstutz, G. C. (ed.), Ore Genesis—The State of the Art, Springer-Verlag, 469-90.CrossRefGoogle Scholar