Stress directions in the eastern part of the Silesian Nappe (Polish Outer Carpathians) reconstructed from the second-order folds

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Abstract


Rekonstrukcja warunków głównego naprężenia poziomego we wschodniej części płaszczowiny śląskiej (Polskie Karpaty zewnętrzne) na podstawie analizy fałdów drugiego rzędu

A study of the second-order folds in the eastern part of the Silesian Nappe allows one to distinguish two groups of structures: longitudinal ones and those orientated obliquely to the strike of the first-order fold axes. Analysis of orientation of the second-order fold axes has made it possible to reconstruct the orientation of Oi stress axes and compression trajectories for each group of folds individually. The results of such a reconstruction imply that the two groups of folds must have been developing independently one from another. Longitudinal folds were formed together with the first-order folds, under the influence of clockwise rotating compression caused by the Early Miocene plate collision, whereas development of the oblique folds was influenced by counterclockwise rotating compression, what seems to be connected with the final push of the Carpathians in Sarmatian times.

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