Rozwój osadów płaszczowiny magurskiej w strefie przypienińskiej

Abstract

DEVELOPMENT OF SEDIMENTS OF THE MAGURA NAPPE IN THE PERI-KLIPPEN ZONE, CARPATHIANS Summary The paper deals with stratigraphy and facial development of the Magura Nappe in the area adjoining the Pieniny Klippen Belt (Carpathians) in Poland (Fig. 1). The most important lithostratigraphic units (both formal and informal) spanning the time from the Albian through the Oligocene, have been described. Facial diversification of the Cretaceous-Paleogene deposits of the southern part of the Magura Nappe (Krynica facial zone) has been compared with more external facial zones (the Sącz and the Rafa zones - Figs 2, 3). Palaeogeography of peri-Klippen part of the Magura Basin has been outlined, with special stress laid upon Palaeogene developments. A considerable facies diversification in the Magura Basin started in Paleocene, and was well evident at the Paleocene/Eocene boundary. This diversification could be related to modifications of the southern margin of the Magura Basin due to Laramian orogeny in the Pieniny Klippen Belt. As a result, new source areas emerged close to the southern boundary of the Magura Basin, active through the whole Eocene. The role of these sources was gradually reduced with time, during a higher part of the Upper Eocene, due to expansion of marine transgression in the Inner Carpathians. Lithofacies distribution in the Magura Basin is analogous to fossil basins of deep-water submarine cones characteristics (19, 3 2). However, our bas in differed in having a comparatively great length (about 600 km) and small width (about 100 km). This suggests that the Magura Basin was supplied from a series of source areas located along its southern margin, characterized by similar geological structure. The analysis of exotic fragments of the Palaeogene strata of the Magura Nappe indicates that these source areas consisted of crystalline cores with Mesozoic sedimentary cover analogous to those known from the Inner Carpathians. A short description of tectonic structure of the southern part of the Magura Nappe is also given (Fig. 4).