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Development of the Turonian/Coniacian hardground boundary in the Cracow Swell area (Wielkanoc quarry, Southern Poland)

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Olszewska-Nejbert D.

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tom Vol. 48, No 2

159--170

EN

During the Turonian and Coniacian, up to the early Santonian, the present-day Polish Jura Chain composed a positive submarine palaeotectonic feature referred to as the Cracow Swell, separating the deeper Opole Trough to the SW from the Danish-Polish Trough to the NE. At present the Turonian and Santonian deposits at themargin of the Polish Jura Chain and the Miechów Trough are fragmentarily preserved. They are characterised by numerous stratigraphic hiatuses and the occurrence ofmany unconformity surfaces.One of themost spectacular unconformities is a hardground at the Turonian/Coniacian boundary described herein from the vicinity of Wielkanoc. Its development took place in several stages. Threemain stages can be distinguished with a compositemiddle stage. In the first stage during the early late Turonian, a gradual drowning of the carbonate Cracow Swell took place followed by eutrophication of the environment. The second stage from the latest Turonian to the earliest Coniacian was linked with a crisis of a carbonate sedimentation leading to its cessation. A firmground with Thalassinoides traces was formed, followed by a hardground with bivalve borings and ?Trypanites. Carbonate- clastic sedimentation recommenced at least twice (with quartz arenites), followed by rejuventation of burrows and/or borings, lithification of the sediment, glauconitization and phosphatization, as well as the development of microbial mats undergoing early phosphatization. This led to the formation of phosphatic stromatolites. In consequence a composite hardground was formed. The third stage took place in the late early Coniacian. Carbonate-clastic sedimentation resumed. Deposits, developed as carbonate arenites with quartz and glauconite admixtures (non-phosphatized), filled the last generation of the rejuvenated burrows and finally covered the hardground.

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Campanian (Late Cretaceous) hexactinellid sponges from the white chalk of Mielnik (Eastern Poland)

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Olszewska-Nejbert D. , Świerczewska-Gładysz E.

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tom Vol. 61, no. 4

383-417

EN

The taxonomic description of the Campanian (Upper Cretaceous) hexactinellid sponges from the white chalk of Mielnik, eastern Poland, is presented. The fauna comprises 19 species belonging to 15 genera, representing by the Hexactinosida and Lychniscosida. The species Polyopesia macropora is described as new. They represent a typical sponge assemblage of the North European Province. Most of the specimens are strongly phosphatized (85% of the material), less common are grey-beige, slightly phosphatized specimens (11%), and distinctly rarer are specimens infilled with white chalk (3%) and silicified specimens (1%). Phosphatization was the dominant fossilization process of the hexactinellid sponges in the white chalk of Mielnik.

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Integrated biostratigraphy of the Santonian through Maastrichtian (Upper Cretaceous) of extra-Carpathian Poland

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Walaszczyk I. , Dubicka Z. , Olszewska-Nejbert D. , Remin Z.

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2016

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tom Vol. 66, no. 3

313--350

EN

The biostratigraphic importance, current zonations, and potential for the recognition of the standard chronostratigraphic boundaries of five palaeontological groups (benthic foraminifers, ammonites, belemnites, inoceramid bivalves and echinoids), critical for the stratigraphy of the Santonian through Maastrichtian (Upper Cretaceous) of extra-Carpathian Poland, are presented and discussed. The summary is based on recent studies in selected sections of southern Poland (Nida Synclinorium; Puławy Trough including the Middle Vistula River composite section; and Mielnik and Kornica sections of south-eastern Mazury-Podlasie Homocline) and of western Ukraine (Dubivtsi). The new zonation based on benthic forams is presented for the entire interval studied. Zonations for ammonites, belemnites and inoceramid bivalves are compiled. All stage boundaries, as currently defined or understood, may easily be constrained or precisely located with the groups discussed: the base of the Santonian with the First Occurrence (FO) of the inoceramid Cladoceramus undulatoplicatus; the base of the Campanian with the Last Occurrence (LO) of the crinoid Marsupites testudinarius and approximated by the range of the foraminifer Stensioeina pommerana; and the base of the Maastrichtian approximated by the FO of the inoceramid bivalve Endocostea typica and the FO of the belemnite Belemnella vistulensis. The positions of substage boundaries, as currently understood, are constrained in terms of the groups discussed.

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Porosphaera globularis (Phillips, 1829) (Porifera, Calcarea) in the Campanian (Upper Cretaceous) of extra-Carpathian Poland

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Jurkowska A. , Świerczewska-Gładysz E. , Dubicka Z. , Olszewska-Nejbert D.

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tom Vol. 65, no. 1

121--139

EN

The stratigraphical distribution of Porosphaera globularis, a common calcareous sponge in the Upper Cretaceous (mostly Campanian and Maastrichtian) of Poland was studied. The presented material, both new and from museum collections, comes from the Campanian of the Miechów Synclinorium, in southern Poland, and from the Lower Campanian of Mielnik in the south-eastern part of the Mazury-Podlasie Homocline, in eastern Poland. The significance of the species in extra-regional correlation, its palaeobiogeography and stratigraphical potential is critically reviewed.