Paleodelta w miocenie przedgórza Karpat
Abstract
MIOCENE PALEODELTA OF THE CARPATHIAN FORELAND
Summary
The Carpathian Foredeep is infilled with marine deposits of the Neogene age. In the external zone of the Carpathian Foreland (Fig. 1), terrigenous Miocene deposits attain 4000 m in thickness, including about 3500 m of Lower Sarmatian (Wielkie Oczy trough). Borehole and geophysical data made it possible to correlate individual clay-sandy, siltstone and evaporite series. The correlations clearly showed a separate position of a zone stretching north of Rzeszów, which is characterized by the lack of cheroical deposits and predominance of sandstones in the Sarmatian. The development of sandstone series may be also traced close to the front of the Carpathians, from Przemyśl to Pruchnik, Łańcut-Husów and Rzeszów, and further westwards. Anhydrites are also frequently lacking in the belt adjoining the Carpathians.
The increase in share of sandstones in the Early Sarmatian resulted from reactivation of tectonic movements after the Late Badenian and in Early Sarmatian (so-called anomalous tectonics). Erosional potential of rivers markedly increased and external part of the Carpathian Foreland was presumably subsiding in the times. Terrigenous material coming to the reservoir was mainly supplied by rivers flowing from the direction of the Metacarpathian Swell.
The main river channel was passing between Leżajsk and Kolbuszowa. Its branching resulted in rapid changes in lithology and highly varying stratification at present recorded in borehole sections. The main river formed typical delta in the above mentioned area north of Rzeszów. Besides the main river, there were also some smaller ones, flowing into the reservoir and forming estuaries (Fig. 1).
Summary
The Carpathian Foredeep is infilled with marine deposits of the Neogene age. In the external zone of the Carpathian Foreland (Fig. 1), terrigenous Miocene deposits attain 4000 m in thickness, including about 3500 m of Lower Sarmatian (Wielkie Oczy trough). Borehole and geophysical data made it possible to correlate individual clay-sandy, siltstone and evaporite series. The correlations clearly showed a separate position of a zone stretching north of Rzeszów, which is characterized by the lack of cheroical deposits and predominance of sandstones in the Sarmatian. The development of sandstone series may be also traced close to the front of the Carpathians, from Przemyśl to Pruchnik, Łańcut-Husów and Rzeszów, and further westwards. Anhydrites are also frequently lacking in the belt adjoining the Carpathians.
The increase in share of sandstones in the Early Sarmatian resulted from reactivation of tectonic movements after the Late Badenian and in Early Sarmatian (so-called anomalous tectonics). Erosional potential of rivers markedly increased and external part of the Carpathian Foreland was presumably subsiding in the times. Terrigenous material coming to the reservoir was mainly supplied by rivers flowing from the direction of the Metacarpathian Swell.
The main river channel was passing between Leżajsk and Kolbuszowa. Its branching resulted in rapid changes in lithology and highly varying stratification at present recorded in borehole sections. The main river formed typical delta in the above mentioned area north of Rzeszów. Besides the main river, there were also some smaller ones, flowing into the reservoir and forming estuaries (Fig. 1).