Dolny mastrycht jako górna granica wieku pelagicznych margli otwornicowych jednostki czorsztyńskiej, Pieniński Pas Skałkowy

Krzysztof Birkenmajer, Antonina Jednorowska


Lower Maastrichtian as Upper age limit of pelagic foraminiferal marls in the Czorsztyn Succession, Pieniny Klipen Belt, Carpathians

Determination of the upper age limit of marine sediments of: the Klippen Successions allows to calculate the duration of stratigraphical hiatus at the base of transgressive Maastrichtian or Palaeogene, caused by Upper Cretaceous folding and denudation of the Pieniny Klippen Belt, Carpathians. This hiatus has a vertical range variable within particular stratigraphic-facial units (successions) and also varies regionally in the Pieniny Klippen Belt (see Birkenmajer, 1970, 1974, 1976). It is shortest in the Czorsztyn Succession in the vicinity of Nowy Targ (Figs 1, 2), between transgressive Maastrichtian molasse (Jarmuta Formation) and brick-red foraminiferal marls of the Pustelnia Marl Member (Jaworki Marl Formation — see Birkenmajer, 1976). Two samples from these foraminiferal marls taken at Mały Rogoźnik stream near Zaskale (Szaflary: Nos 301, 302 — see Alexandrowicz et al., 1962) yielded microfaunas suggesting an Upper Campanian and Maastrichtian age. One of the samples (No 302), as well as another sample from the vicinity of Krempachy, east of Nowy Targ (Alexandrowicz, 1966, Fig. 27) yielded, moreover, Globotruncana mayaroensis Bolli which, by modern standards, is indicative of Upper Maastrichtian. The correct determination of this species has been questioned (Alexandrowicz et el., 1968 b; Birkenmajer, 1970), likewise the presence of Maastrichtian in pelagic foraminiferal marls of the Czorsztyn Succession was open to doubt. The revision of microfauna from the above samples did not confirm the presence of Globotruncana mayaroensis, neither were the Upper, nor the Middle Maastrichtian indices found. The microfaunal assemblage studied is rich and consists of boith benthonic and planik tonic foraiminifers. Arenaceous benthos is least abundant: Gaudryina rugosa (d’Orbigny), Dorothia trochoides (Marsson), Tritaxia subparisiensis (Grzybowski), T. capitosa (Cushman), Spiroplectammina baudouniana (d’Orbigny), Spiroplectammina jarvisi Cushman and Goesella rugosa (Hanzlikovà). Calcareous benthos is more frequent; Lagena vulgaris Williamson L. apiculata Reuss, Dentalina oligostegia Reuss, Nodosaria limbata (d’Orbigny), Fissurina orbignyana Sequenza, Aragonia trinitatensis (Cushman et Jarvis), A. velascoensis (Cushman), Eponides praemegastomus Mjatliuk, E. subcandidulus (Grzybowski), E. lotus (Schwager), Bolivinoides draco miliaris Hiltermann et Koch, Gyroidinoides globosus (Hagenow), Globorotalites micheliniana (d’Orbigny), Quadrimorphina allomorphinoides Reuss), Heterolepa sparksi (White) and Stensioeina pommerana Brotzen. Uncommon are the following planktonic forms: Heterohelix globulosa (Ehrenberg), H. striata (Ehrenberg), Praeglobotruncana citae Bolli, P. havanensis (Voorvijk), Globigerinelloides aspera (Ehrenberg) and G. biforaminata (Hofker). Very common are calcareous planktonie forms of the genus Globotruncana: Globotruncana stuarti (Lapparent), G. stuartijormis Dalbiez, G. caliciformis (Lapparent), G. contusa scutilla Gandolfi, G. rosetta Carscy, G. fornicata Plummer, G. linneiana linneiana '(d’Orbigny), G. linneiana tricarinata (Quereau), G. linneiana Vogler, G. area Cushman and G. conica White. The above Globotruncanas allow to determine the age of the youngest pelagic foraminiferal marls of the Czorsztyn Succession (Pustelnia Marl Member, uppermost part) as Lower Maastrichtian, Globotruncana stuartiformis Zone (Tab. 2). The Maastrichtian age is also confirmed by the occurrence of Heterolepa sparksi (White) which is known from the Maastrichtian and Paleocene, e.g. from the Maastrichtian of Czechoslovak Carpathians (Hanzlikova, 1972). The marls of the Pustelnia Marl Member are known as secondary deposit in sedimentary breccias of the Jarmuta Formation (Maastrichtian) exposed in the close vicinity of our foraminiferal sample sites at Szaflary and Zaskale. Thus the sedimentary hiatus between the Pustelnia Marl Member and the Jarmuta Formation in the vicinity of Nowy Targ is very short, and should correspond to a middle part of the Maastrichtian (Tab. 1).

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