Nowe dane o permie wschodniej części syneklizy pery bałtyckiej

Abstract

NEW DATA ON THE PERMIAN DEPOSITS IN THE EASTERN PART OF THE PERI-BALTIC SYNECLISESummaryThe paper presents new data on the Permian deposits, found to occur in the north-eastern areas of Poland. Intense geological and drilling activity, recently carried on in this region, allowed both thickness map and map of main, Permian facies extents (Figs. 1–7) to be drawn. Clastic deposits, related here to the Lower Permian, extend somewhat farther to the west than previously suppossed. The thickness of the Lower Permian deposits strongly depended upon the morphology of the sub-Permian surface (Figs. 1 and 2). The form of this surface was them affected by some older dislocation zones and by a petrographical differentiation of the rocks in the sub-Permian basement.Both the character and the thickness of the Zechstein deposits, depended here mainly upon the sea bottom morphology which was·strongly affected by vertical movements of the sub-Permian basement (Fig. 1). These phenomena have already before been emphasized by S. Tyski (l967, 1968). During the sedimentation of the Zechstein lower members (Figs. 4–6) the sea bottom was being uplifted and the elevations were characterized almost by a meridional direction (Zaręby – Dębowiec and region of Pasłęk). The greatest extent and the greatest depth of the Zechstein sea were characteristic of the Werra cyclothem, thus at present the greatest thicknesses may be encountered here in the deposits of this age (Figs. 5, 8–10). In a. zone situated near the south shore of the sedimentary basin, carbonates precipitated in this cyclothem on a large scale forming deposits, of maximum thickness Somewhat farther offshore and on the elevations, sulphates produced thick deposits, and in the depressions – salts were laid down (Fig. 4). The results of the recent drillings proved the conclusions drawn by S. Tyski and R. Wagner as to the asymmetric character of the Zechstein basin and the gradual displacement of the basin axis to the south. Although the complex of the Stassfurt sediments does not, as a whole, rest transgressively on the formations of the Werra cyclothem, the Stassfurt chloride facies are observed to occur more southwards than the Werra salts (Fig. 10). On the other hand, the sediments of the Leine cyclothem distinctly overlap the Stassfurt formations and, within the southern part of the area in study, also the Werra ones (Figs. 9 and 10).