Porosity distribution of minerals forming crystalline rocks

摘要

The porosity characterisation of a crystalline matrix are classically described by a bulk parameter or a pore size distribution. Nevertheless, it also appears important to analyse the heterogeneity of porosity distribution against rock chemistry (e.g. the mineralogy). The porosity map of granitic rock core sections was obtained using the ~(14)C-MMA impregnation and autoradiograph methods. The map of the rock forming primary mineral was obtained on the same sections and at the same scale by a selective staining technique. The superimposition of the two images allows a study of the relations between mineral species and local rock porosity. The effects of alteration were studied comparing the porosity - mineral relations in fresh and altered samples of the Sievi tonalite and the Kivetty granite. During alteration, the mineral specific porosity distribution curves are shifted toward the large porosity, and furthermore the distributions are broadened. The shape of all the distribution are well adjusted with log-normal or combination of log-normal distribution.