Uwagi o sedymentacji aalenu fliszowego i warstw jarmuckich pasa skałkowego

Krzysztof Birkenmajer


Remarks on the sedimentation of the Aalenian Flysch and Jarmuta beds (Senonian) of the Pieniny Klippen Belt

Two Flysch members of the Pieniny Klippen belt (Central Carpathians), one of the Aalenian and the other , off the Campanian-Maestrichtiari1 age have been described. The Aalenian Flysch sedimentary complex belongs mainly to the Branisko series, and partly also to the Niedzica and Czorsztyn one. It consists of black and blacky-grey, micaceous sandstones and shales with thin intercalations of coal and crinoidal grey limestones. Fossils are very unfrequent and besides Posodonomya alpina only belemnites and aptychi have been found. Sandstones, siltstones and crinoidal limestones are graded or laminated. The most common type is the normal graded bedding terminating with several laminae with or without the normal gradation (composite bedding). Inverted symmetrical and asymmetrical graded bedding are less common. Undulate (convolute and slip) beddings are less frequent than those described above. Hieroglyphes on the under side of the layers are of mechanical and organic origin. The Aalenian Flysch has been deposited mainly in the central part of the Pieniny Klippen-series geosyncline. There was a cordillera during the Aalenian which emerged in the Lower Aalenian and was submerged in the Middle and Upper Aalenian. Aalenian deposits in the Pieniny Klippen belt represent the oldest Flysch sediments in the Carpathians. The Flysch sedimentation of th a t age does not correspond to any stronger orogenic stage and had been finished long before the first Middle Cretaceous orogenic movement in the Pieniny. This does not agree with the opinion of J. Tercier (1947) who regards the Flysch deposits as formed shortly before an orogenic stage. The Jarmuta beds (Campanian-Maestrichtian) are the most important member of the Cretaceous mantle in the Pieniny Klippen belt of Poland. They were deposited transgressively over the Middle Cretaceous tectonic units of nappe character. Four facies. of the Jarmuta beds were distinguished by the author. The first one, of supralittoral origin consisting of gravels and poorly cemented conglomerates, had been deposited by rivers above the sea level. Among the boulders several percent is of local origin, but about 90 per cent are exotics. In the supralittoral gravel deposits the fauna is lacking. The second facies is the cliff-facies, several metres thick, deposited in the most shallow marine water. It consists of the local Klippen series material. Cliff deposits are poorly sorted, angular-shaped and feebly bedded. Fragments of inocerams and oysters have been found here. Third facies, deposited in deeper waters consists of sandstones and conglomerates. Its thickness in the most southern pa rt of the primary basin is about 30 m, to the north it rises up. to 150 — 200 m. Graded bedding is the most common type; besides it laminated bedding is also frequent. Undulated (convolute and slip) bedding is rare. Current (diagonal) bedding was not observed. Direction of the transport reconstructed on the basis of flow marks and groove casts, in the sandstone conglomerate facies is from the south to the north. Fossils are very unfrequent: detritus of inocerams and large foraminifera. The fourth, Flyseh fades is of the deepest origin. It consists of sandstones interbedded by shales with intercalations of conglomerates. Among the bedding types, the graded and laminated ones are the most frequent and of similar proportions. Slip and convolute beddings are more frequent than in the preceding facies, current (diagonal) bedding is found rarely. Flow marks and groove casts indicate the NNW, NNE also ENE and WSW direction. This suggests th a t turbidity currents coming from the south changed their way in the deepest parts of the sedimentary basin. The thickness of the Flysch facies rises up to 500 m.

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