Application of quantitative X-ray diffraction analysis by the Rietveld method to VHMS alteration halo studies

Qualitative and quantitative determinations of the mineralogical compositions of hydrothermally altered wall rock samples and the identification of possible mineralogical zonations within altered zones associated with VHMS deposits by the means of X-ray diffraction analysis by the Rietveld method can now be performed as a matter of routine. Expressed as chemical analyses, these results are in good agreement with the major oxide compositions determined by X-ray fluorescence. Systematic errors that are caused by layer disorder of phyllosilicates, preferred orientation of particles, and microabsorption are minimised by the described procedure of sample preparation and analysis.