Wstępne wyniki badań nad spękaniami ciosowymi w jednostce skibowej (skolskiej) Karpat Ukraińskich

Abstract

JOINTING IN THE SKIBA (SKOLE) UNIT, UKRAINIAN CARPATHIANS Summary The Skiba (Skole) nappe is composed of a number of imbricated slices thrust one up on another in the middle-IateMiocene times. In a SW -NE oriented profile, these are Slavsko, Rozhanka, Zelemianka, Parashka, Skole, Orovska and Beregovaya(marginal) slices, whose lithostratigraphic inventory includes Upper Cretaceous throughOligo-Miocene flysch sequences of differentiated thicknesses. Joints and shear/hybrid shear fractures have been measured at some 40 stations equally spaced throughout all but the marginal slices of the Skibanappe along the Opir river section. The fractures are mostly kathetal ones and cluster into two to three cross-fold sets, accompanied by a single orogen-parallel set. The axes of maximum stress associated with jointing usually trend NE-SW to W -E, as far as Paleogene and Miocene strata are concerned, being subperpendicular to the overall strike of thrusts and folds. In the Upper Cretaceous strata, however, the axes in question strike N-S to NNE-SSW. These results suggest that jointing must have been coeval with folding and thrusting of the Skibanappe.