International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

Depositional architecture, sequence stratigraphy and geodynamic development of the Carpathian Foredeep (Czech Republic)

Pages: 53 - 69

Authors: SLAVOMIR NEHYBA, JAN SIKULA

Abstract: Five 3rd-order depositional sequences were recognized within Neogene infill of the Carpathian Foredeep. Individual sequences are characterized by the diverse shape and extent of the basin, by characteristic depositional architecture and lithofacies. Their deposition was controled by the principal ruling factors, namely eustasy, tectonics, sediment supply, and basement morphology. 4th-order depositional sequences (transgressive-regressive cycles) are also identified within the 3rd-order depositional sequences. Depositional sequences are related to three distinct stages of the geodynamic history of the basin. The pre- (“main”) collisional stage (Egerian/Eggenburgian) is represented by sequence I and was ruled by eustasy, sediment-supply rate and basement relief. The collisional stage (Eggenburgian–Late Karpatian) is represented by three sequences. Sequence II (Eggenburgian–Early Karpatian) reflects the initiation of thrusting due to loading of the West Carpathian accretionary wedge. This process was mainly responsible for creation of accommodation space, while the other factors were supplementary. Sequence III (Karpatian) was ruled mainly by interactions between tectonic/flexural subsidence and isostatic rebound associated with the forebulge migration toward the foreland and thrust front. Sequence IV (Late Karpatian) is the upper part of the clastic wedge and reflects the main collision and rapid subsidence in the foreland basin. The depositional architecture was dominantly driven by tectonic processes. The post- (“main”) collisional stage (Early Badenian) is identical with sequence V, which was ruled both by eustasy and tectonics. Accommodation space (incised valley?) developed in the internal parts of the basin.

Keywords: Neogene, Carpathian Foredeep, peripheral foreland basin, depositional sequences, transgressive-regressive cycles

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