Volcanism And Uranium Mineralizations- The Concept Of Source Rock And Concentration Mechanism

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Journal Article: Volcanism And Uranium Mineralizations- The Concept Of Source Rock And Concentration Mechanism

Abstract
Comparative mineralogical, petrographical and geochemical studies were undertaken in several places in the world, Sierra Pena Blanca (Mexico), Macusani field (Peru), Meseta Los Frailes (Bolivia) and Puna (Argentina), in order to understand the behaviour of uranium in volcanic environment and to define the characteristics of a volcanic source rock and the main concentration mechanisms. Our results indicate: 1. (1) A fertile volcanic rock is alumina- and alkali-rich (alumino-potassic in the granite terminology). Alkaline, subalkaline and calc-alkaline volcanics are much less favorable. 2. (2) Because of the stability of the accessory minerals during all the events which occur during and/or after the cooling of the volcanic formations, uranium is only leached from the matrix. Thus the leachable metal stock is directly related to the proportionate volume of the matrix and to its U content. 3. (3) The early post-magmatic stages, such as the high-temperature devitrification and the vapor phase crystallization, concentrate the previously disseminated uranium at the mineral scale and increase the efficiency of the subsequent leaching stages. The glass hydration does not mobilize uranium. 4. (4) The uranium deposits spatially related to volcanism may result from different processes, either hydrothermal and related to the volcanic activity, or supergene. The host rocks may be the volcanic rocks themselves or the surrounding country rocks.

Authors 
Jacques L. Leroy and Brigitte George-Aniel








Published Journal 
Journal of Volcanology and Geothermal Research, 1992





DOI 
Not Provided
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Citation

Jacques L. Leroy,Brigitte George-Aniel. 1992. Volcanism And Uranium Mineralizations- The Concept Of Source Rock And Concentration Mechanism. Journal of Volcanology and Geothermal Research. (!) .