Neotektonika polskich Karpat zewnętrznych w świetle wybranych parametrów morfometrycznych

Abstract

NEOTECTONICS OF THE POLISH OUTER CARPATHIANS IN THE LIGHT OF SOME MORPHOMETRIC PARAMETRES Summary The aim of this paper is to present the differentiation of some morphometric parametres, introduced by Bull and McFadden [6], including the width of the valley floor (Vfw), altitudes of the left (Eld-Esc) and right valley divides (Erd-Esc) , as well as the valley floor width-valley height ratio (Vf) that have been calculated for the main Carpathian river valleys. All the discussed morphometric parametres differ throughout the Polish Outer Carpathians and cluster into a number of zones that could be correlated with neotectonically (Pliocene-Quaternary) active areas. Some of them are delimited by thrusts, faults or large regional photolineaments, whereas the others simply mark uplifted regions independent of older tectonic structures, although being parellel to the general strike of the Outer Carpathian thrust sheets. The spatial distribution of the zones in question is peculiar for two reasons: first, they generally parallel fold and thrust axes, secondly - they become more numerous to the east of the Dunajec river valley. Moreover, some of these structures are located at or even in front of the present-day Carpathian frontal thrust. Such a pattern could suggest an eastward-increasing tectonic activity of the Carpathian realm, the character of which is probably due to some remnant folding within the flysch cover. This conclusion is also supported by the fact that the width of high-activity zones rarely exceeds 10-15 km, and that the Carpathian sole thrust represents a fairly regular surface [19], undisturbed by faults occurring in the substratum. This excludes a possibility of block-type motions within the Carpathian basement, as well as isostatic movements of such small-scale blocks of the flysch cover. Remnant horizontal stresses within the flysch nappes in the eastern part of the Polish Carpathians have already been suggested by Liszkowski [16] and Zuchiewicz [31,34].