PREPARATIVE METHOD AND ANALYSIS BY OM, SEM AND EPMA OF POROUS, BRITTLE AND LOW PERMEABILITY ROCKS AND MATERIALS - THE CASE OF PUMICES

A method is reported for the preparation of flat specimens (30 mu m th ick) of porous, brittle and low permeability materials and locks for b oth optical microscopy (OM), scanning electron microscopy (SEM) and el ectron probe microanalysis (EPMA). The method, based on alternating em beddings in vacuum with epoxy resin and grindings with final polishing down to 0.25 mu m alumina grain size, prevents the breaking of the gl assy interconnections and fills with resin the majority of the bubbles and voids. It has been applied to the analysis of pumices sampled at Linosa, Sicily, which are glassy materials with inhomogeneities on a m icro-scale and with a vesicular texture often not interconnected. The method has been successfully applied also to the preparation of variou s sedimentary rocks, synthetics, bones and biomaterials.