2017 Volume 58 Issue 2 Pages 80-93
Mode of crystalline rock（granitic rocks）is important information for evaluating their formation process, characterizing fracture distribution and understanding mass transfer in the rock matrix. To evaluate the mode, methods such as point-counting and several image analyses have been applied. However, these methods have several issues in evaluating the mode of crystalline rock. Thus, this study provides the new image analysis method（MJPD method）using elemental map obtained by scanning X-ray analytical microscope（SXAM）for evaluation of mineral distribution and mode including the secondary minerals which have the similar chemical composition to the primary minerals. The MJPD method does not need the standard minerals and can also deal with the heterogeneity of elemental distribution in each mineral. For evaluating the applicability of MJPD method, this method was applied to elemental maps, which was measured by SXAM several times, in thin sections（approximately 20mm × 30mm）of altered and unaltered granitic samples. As a result, it was found out that the mineral distribution and mode are easily evaluated by MJPD method using the elemental maps measured in approximately 10,000 seconds, compared with the ones by existing point-counting method. In addition, the MJPD method has the potential for expanding the applying range because this method can also be applied to the elemental maps obtained by other analytical instrumentation such as EPMA and SEM-EDS.
