International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

JOINTING IN THE SILESIAN NAPPE (OUTER CARPATHIANS, POLAND) - PALEOSTRESS RECONSTRUCTION

Pages: 315 - 325

Authors: LEONARD MASTELLA, ANDRZEJ KONON

Abstract: The joint network in the Silesian Nappe is composed of a shear system (diagonal sets — SR, SL) — striking in the present position at high angles to map-scale fold axes, a single extension set T — striking sub-perpendicular to these axes, fold parallel joints L and L´ striking parallel or at small angles to map-scale fold axes. For paleostress reconstructions penetrative SR, SL and T joint sets were analysed from 197 outcrops. In the paleostres analysis the angular difference between the σHmax directions calculated from shear (SR, SL) and extension T joints is notable. The angular difference between these σHmax directions suggests that it is a result of a slight tectonic bending of the investigated Silesian Nappe arc, which took place between the nappe thrusting phase and the proceeding uplift phase of this part of the Outer Carpathians arc.

Keywords: Miocene, Oligocene, Outer Carpathian arc, Silesian Nappe, tectonic bending, shear and extensional joints, paleostress

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