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Jurassic evolution and the structure of the central part of the Pieniny Klippen Belt (Carpathians) in Poland – new insight from the Czertezik Succession type area

Wierzbowski Andrzej, Wierzbowski Hubert, Segit Tomasz, Krobicki Michał

Volumina Jurassica

2021

Vol. 19, no. 1

21--60

The Czertezik Succession of the Pieniny Klippen Belt in Poland is assigned herein to its type area of occurrence – the main Pieniny Range, between Zamkowa Góra and Czertezik mounts. The reworked deposits of uppermost Pliensbachian, Toarcian and possibly Aalenian to lowermost Bajocian discovered in crinoidal limestones which indicate redeposition processes, especially during the Bajocian, are considered to be clearly important for reconstructing the depositional history. The redeposited Pliensbachian is represented by clasts of spotty limestones, the Toarcian by ferruginous grains and fragments of crusts/large oncoids of the ammonitico-rosso type (?Adnet Fm.), whereas the Aalenian and lowermost Bajocian is possibly represented by clasts of siliciclastic deposits and phosphatic nodules. This part of the succession resulted from the activity of rifting phases at the end of the Early Jurassic, and in the Bajocian, which caused the development of the special sedimentary environments typical of the Czertezik Succession. The younger Middle to Late Jurassic deposits represented by nodular limestones, radiolarites and micritic well-bedded limestones show a less distinct facies pattern, which is in part similar to that of other successions of the Pieniny Klippen Belt, although some rock-units such as the newly established Zamkowa Góra Bed, revealing the continuation of redeposition processes, remain specific to the Czertezik Succession. The Jurassic structure of the central part of the Pieniny Klippen Belt in Poland is revised due to the introduction of the Czertezik Ridge as a new palaeogeographic unit being the place of deposition of the Czertezik Succession. The revised position of the deposits shifts the structural affinity of the Czertezik Succession from the Subpieniny Nappe to the base of the Pieniny Nappe sensu Uhlig, 1907, and implies its closer palaeogeographic position to the Branisko–Pieniny successions than to the Czorsztyn–Niedzica successions as has been interpreted so far.

Ammonite stratigraphy and organic matter of the Pałuki Fm.n(Upper Kimmeridgian–Lower Tithonian) from the central-eastern part of the Łódź Synclinorium (Central Poland)

Wierzbowski Andrzej, Wierzbowski Hubert

Volumina Jurassica

2019

Vol. 17, no. 1

49--80

The ammonite biostratigraphy as well as the organic matter content, its type and maturity of the Pałuki Formation, belonging to the fine, siliciclastic Kimmeridge Clay type facies, were investigated in five deep boreholes from the central-eastern part of the Łódź Synclinorium in Central Poland. The studied deposits are assigned to the Eudoxus and Autissiodorensis zones of the Upper Kimmeridgian as well as the Klimovi, Sokolovi, Pseudoscythica and Puschi (=Tenuicostata) zones of the Lower Tithonian (“Lower Volgian”). The Pałuki Formation shows in its lower and middle parts average TOC concentrations of ca. 2.5 wt.% and prominent, restricted increases in organic matter content, which are found in the mid-Eudoxus Zone, the lowermost part of the Autisiodorensis Zone, and at the Sokolovi–Pseudoscythica zone boundary. These stratigraphical intervals correlate well with rich in organic matter levels present in the Kimmeridge Clay Formation of NW Europe. The periodic expansions of Submediterranean and Subboreal-Boreal ammonites corresponded mostly to the transgressive phases, often correlated with a higher content of organic matter. The development of special morphologies of ammonites, such as the small-sized, nectopelagic forms of Nannocardioceras in the Late Kimmeridgian, has also been related to the deposition of shales rich in organic matter during the transgression maxima. The organic matter present in the Pałuki Formation mostly consists of Type II kerogen and is immature or early mature with respect to hydrocarbon generation, which is in agreement with previously published data. Evaluation of the new and published geochemical, lithological and structural data from the Pałuki Formation in the central-eastern part of the Łódź Synclinorium shows that these deposits could not have been a considerable source of crude oil or gas.