Stratygrafia mikropaleontologiczna miocenu w centralnej części zapadliska przedkarpackiego

Ewa Odrzywolska-Bieńkowa



The paper presents the results of studies on the microfauna from core material of the Miocene drilled in the Rozwadów, Mielec and Sandomierz areas. The studies also comprised the microfauna present in clays intercalating chemical Miocene deposits penetrated by Jamnica O-15, Jamnica L-21, Opalona Góra L-12, Stalowa Wola S-15 and Studzieniec D-16 drillings. The oldest deposits of that region, previously assigned to Kładnica Beds (Miocene M3), are characterized by the microfauna of the brackish type and with the predominance of the species Ammonia beccarii. They are represented by dark non-calcareous clays with pyrite. The younger deposits include: Lithothamnium limestones and marls and Nullipora sandstones and siltstones characterized by numerous foraminifers of the genera Amphistegina, Elphidium and Cibicidoides. The microfauna is here markedly scarcer than in typical zone with Orbulina suturalis, distinguished in Lower Badenian Baranów sandstones and marls. The upper part of the Badenian is represented by siltstone marly and sandy clayey deposits with glauconite and rich foraminifer assemblage including guide species Uvigerina costai. The Badeniafl strata occurring above the chemical deposits in this area are assigned to the Neobulimina longa and Hanzawaia crassiseptata zones. The zones comprise a series of alternating marly clays and blocky marls. The Sarmatian is primarily represented by the deposits of siltstone-marly facies and it may be divided into the Anomalinoides dividens, Cycloforina karreri ovata, Varidentella sarmatica and Elphidium hauerinum zones. The most interesting results of the present study include the finds of the microfauna with Ammonia beccari analogous to that known from Kłodnica Beds (Miocene M3) in the basal parts of the borehole sections and of the assemblages of innumerous foraminifers in the clays intercalating chemical Miocene deposits. Up to the present the clay intercalations were considered to be faunistically barren except for fish remains. Lower and Upper Badenian and Sarmatian foraminifer zones distinguished here appear to be comparable with contemporaneous zones distinguished in the areas of the U.S.S.R. and Czechoslovakia.

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