Rozwój spękań w skałach metamorficznych Gór Orlickich (Sudety)
Abstract
Development of fracturing in metamorphic rock of the Góry Orlickie (Sudetes)
Three fracture systems were recognized in metamorphic rocks of the Góry Orlickie. It was ascertained that fractures and kink folds display a certain genetic affinity and that the fractures are generally parallel to the kink surfaces. Conjugate complementary kink folds of three sets differing in their age were used to reconstruct the orientations of the principal axes of successive stress fields. It was assumed that the development of the kink folds was accompanied by the formation of penetrative weakened planes parallel to the kink surfaces. These planes of weaknesses concordant with directions of the residual stresses, were transformed into actual fractures during postorogenic uplift and relaxation. Kinking and fracturing if metamorphic rocks of the investigated region were referred to the tectonic forces connected with the formation of the Intrasudetic Basin in the Carboniferous period.
Three fracture systems were recognized in metamorphic rocks of the Góry Orlickie. It was ascertained that fractures and kink folds display a certain genetic affinity and that the fractures are generally parallel to the kink surfaces. Conjugate complementary kink folds of three sets differing in their age were used to reconstruct the orientations of the principal axes of successive stress fields. It was assumed that the development of the kink folds was accompanied by the formation of penetrative weakened planes parallel to the kink surfaces. These planes of weaknesses concordant with directions of the residual stresses, were transformed into actual fractures during postorogenic uplift and relaxation. Kinking and fracturing if metamorphic rocks of the investigated region were referred to the tectonic forces connected with the formation of the Intrasudetic Basin in the Carboniferous period.