BRZEŻNE FACJE BADENU I SARMATU DOLNEGO ZBIORNIKA PRZEDKARPACKIEGO W SE POLSCE I ZACHODNIEJ UKRAINIE - WYNIKI BADAŃ OSTATNIEGO DWUDZIESTOLECIA

Abstract

MARGINAL FACIES OF BADENIAN AND LOWER SARMATIAN OF THE FORE-CARPATHIAN BASIN IN SE POLAND AND WESTERN UKRAINE - RESULTS OF RESEARCH DURING THE LAST TWO DECADESAbstract. Lithological characteristics of Middle Miocene strata of the Roztocze region (SE Poland and western Ukraine) is summarized. The Lower Badenian sequence begins with transgressive quartz sands and sandstones that subsequently are passing laterally into marls and coralline algal limestones. They originated in shallow-water, high-energy marine environment. The chemistry of waters at that time as well as during subsequent gypsum sedimentation fluctuated quite considerably. Middle Badenian gypsum deposits build a wide marginal sulphate platform. In shallower parts of the basin the Ratyn Limestone deposits cover gypsum: they are related genetically to new marine transgression. During the Late Badenian the Roztocze region was a transit zone for bioclastic and terrigenous material, and the grainy material was transported owing to waves and wave-generated currents as well as mass movements. The Lower Sarmatian carbonates of Roztocze show a typical facies and poor taxonomic composition of fossil assemblages that indicate abnormal environmental conditions-decreased water salinity and its oversatitration in respect to calcium carbonate.