The geometry and morphology of joints have been examined in the flysch rocks in the western part of the Podhale synclinorium. They form a regular network, which has been developed in several stages connected with the structural evolution of the synclinorium. The initiation of the oldest diagonal system (DR, DL sets), in the form of strength anisotropy in horizontal beds, took place during the successive increase in NNE–SSWcompression. The formation of the majority of the L’ set and of a small portion of the L set took place during gentle open folding connected with the setting of the general structural framework of the synclinorium. The beginning of the formation of the T set was related to WNW–ESE extension connected with the uplift of the synclinorium. The youngest joints – the majority of the L and a small portion of the L’ set, were formed as the result of stress relaxation in the rock masses during progressive uplift lasting up to recent times. The formation of the joints proceeded in two stages: (I) their initiation in the form of joint-anisotropy and (II) opening of joints. These stages have often been significantly separated in time. Sometimes the process of joint opening continues up to recent times. There is a regional tendency that the double shear angle (2Θ) values increase from the axial zone towards the marginal parts of the synclinorium, as well as downward in the flysch lithostratigraphic section. This is probably caused by the increase in confining pressure and rock ductility attributed to the increase in overburden load. The 2Θ values could also have been controlled by tectonic factors.
