Low-temperature hydrothermal interactions between granite and solutions containing Cs, Rb, and Sr: an experimental approach

 

Authors: Drábek M

Published in: Bulletin of Geosciences, volume 80, issue 2; pages: 145 - 148; Received 28 June 2004; Accepted in revised form 11 March 2005;

Keywords: hydrothermal alteration, Cs, Rb, Sr, pollucite, rock-waste interaction, granite,

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Abstract

This paper summarizes the results of low-temperature hydrothermal experiments in which solutions containing Cs, Rb, and Sr were allowed to react with medium-grained biotite granite from Podlesí (Krušné hory Mts., Czech Republic). The experiments were performed at 115 and 150 °C under < 0.5 kbar hydrostatic pressure, for durations of 1872-5562 hours. In these experiments, hydrothermal solutions containing Rb and Sr did not react with the rock-forming minerals in the granite. However, the Cs-containing solution did react with the rock-forming minerals, particularly the feldspars, to produce pollucite, a secondary Cs aluminosilicate. Pollucite could thus be used to delineate migration pathways of solutions through the granite samples. Three important migration pathways were distinguished: microcracks, grain boundaries, and cleavage planes. We also discuss the influence of sample processing on the observed permeability, and the effect of the crystallization of secondary phases on the disproportion between the sorption - desorption coefficients.