Abstract <p>The results of a comprehensive study aimed at quantifying the paleofiltration characteristics of the host rocks of the Tuyukan ore cluster (Mamsko-Chuisky District, Irkutsk oblast) are presented. The work is based on the use of a special technique of microstructural analysis, which includes automated microcrack detection from photopanoramas of oriented thin sections. The petrographic analysis determined the types of rocks and tectonites. The comparison of petrographic data with quantitative parameters of microstructures revealed the relationship between filtration properties, the type of tectonite, and the deformation nature. The obtained results allowed for the identification of rock clusters with different filtration characteristics within the study area, which is directly related to the history of their tectonic transformations.</p>