Potassium feldspars in the Smrekovec volcaniclastic rocks - a byproduct of the reaction from laumontite to analcime

Abstract

Smrekovec volcaniclastic rocks are characterised by several zeolite reactions among which the replacements of laumontite by analcime are the most outstanding. Analcime formed by the reaction from laumontite contains from 2,1-2,3 % of calcium and 0,5 % of potassium which occupie the Na-sites. Potassium, released by the decomposition of laumontite was partially incorporated in the analcime lattice, but the majority is concentrated in tiny exsolutions of potassium feldspars.