EVOLUTION OF LATE CRETACEOUS–PALAEOGENE SYNOROGENIC BASINS IN THE PIENINY KLIPPEN BELT AND ADJACENT ZONES (WESTERN CARPATHIANS, SLOVAKIA): TECTONIC CONTROLS OVER A GROWING OROGENIC WEDGE

摘要

The Pieniny Klippen Belt and neighbouring zones of the Western Carpathians represent an ancient accretionary wedge that developed during the meso-Alpidic (Coniacian–Eocene) tectonic epoch. After an overview of the extensive literature data, the authors present an interpretation of the synorogenic sedimentary record of these zones as being related to various environments of the foreland basin system consisting of the trench-foredeep and wedge-top depositional areas. The peripheral trench-foredeep depozones migrated from the South Penninic-Vahic oceanic realm towards the Oravic continental fragment in an intra-Penninic position, where the synorogenic deposits were laid down with coarsening- and thickening-upward trends before being overthrust by the propagating orogenic wedge tip. The development of wedge-top, piggyback basins (Gosau Supergroup) was controlled by the dynamics of the underlying wedge, composed of frontal elements of the Fatric and Hronic cover nappe systems of the Central Western Carpathians (Austroalpine units). Several compressional and extensional events are documented in the complex sedimentary and structural rock records within the wedge and related basins. The successive transgressive-regressive depositional cycles and corresponding deformation stages are interpreted in terms of a dynamic accretionary wedge that maintained the critical taper only transiently. The supercritical taper states are reflected in regression, shallowing and erosion in the wedge-top area, while the trench was supplied with large amounts of clastics by various gravity-flow types. On the other hand, the collapse stages tending to subcritical wedge taper are indicated by widespread marine transgressions or ingressions in the wedge-top area and a general deepening of all basins to bathyal conditions. Accordingly, the evolution of the entire trench-foredeep and wedge-top basin systems was principally controlled by the complex interplay of the regional tectonic evolution of the Alpine-Carpathian orogenic system, local wedge dynamics and eustatic sea-level fluctuations.