The Late Cretaceous of the Pieniny klippen belt and Marmarosh klippen zone of the Ukrainian Carpathians: paleoceanography by foraminifera

Abstract

In presented article, on the basis of foraminiferal analysis and using the sedimentological data, the stratigraphy of the Upper Cretaceous deposits of the Pieniny Klippen Belt and the Marmarosh Klippen Zone is summarized and clarified, and the features of paleoceanography, in particular the paleobathymetry of sedimentatary basins, were reconstructed. An analysis of the taxonomic composition and morphological features of foraminifera were carried out, as well as of the planktonic/benthic ratio was calculated, on the basis of which the paleoenvironment for foraminifera were reconstructed. Three types of deep-sea foraminiferal assemblages were identified in the studied sediments based on a comparison of the foraminiferal assemblages with the Upper Cretaceous biofacies of the Western Mediterranian and adjacent areas. The assemblages (1) of agglutinated foraminifera belonging to the deep-water agglutinated foraminifera (DWAF) are indicating a bathyal–abyssal below the calcite compensation depth (CCD). These assemblages were found only in the Marmarosh Klippen Zone in low-thickness (25 m) Turonian–Santonian red argillites in the lower part of the Puchov Formation, as well as in the flysch deposits of the Jarmuta Formation. Small-sized foraminifera with a fine-grained wall texture, which belong to the genera Ammodiscus, Haplophragmoides, Labrospira, Pseudobolivina, Plectorecurvoides, Praecystammina, Uvigerinammina, Gerochammina suggesting pelagic sedimentation below CCD are common in the lower part of the Puchov Formation in the Marmarosh Klippen Zone. The assemblages (2) are characteristic for the basin slope with depths above the CCD, and represented by mixed agglutinated, calcareous benthic and planktonic foraminifera. They are characterized by the predominance of the benthic specimens, which make up 70-80% of foraminiferal remains. Assemblages (2) were also found in sediments of the Marmarosh Klippen Zone, such as the upper part of the Santonian and Campanian sediments of the Puchov Formation. They contain siliceous or calcareous-siliceous DWAF (mainly genera Kalamopsis, Caudammina, Karrerulina, Spiroplectammina, Tritaxia, Dorothia, Marssonella), calcareous benthic foraminifera (mainly genera Pleurostomella, Eponides, Globorotalites, Anomalina, Reussella). Planktonic foraminifera have mainly large keeled shells typical for deep sea areas and belong to the genera Globotruncana, Globotruncanita, and Abathomphalus. The assemblages (3) are plankton-dominated with admixture of the DWAF and calcareous benthic foraminifera. The assemblages are characteristic of marls accumulated at depths above the CCD on continental slopes in the bathyal conditions of the open ocean. They are common in the Upper Cretaceous of the Pieniny Klippen Belt, where were found in the tops of the Tyssalo Formation (Cenomanian), Puchov Formation (Turonian–Maastrichtian), and Jarmuta Formation (Maastrichtian). Planktonic foraminifera have mainly large keeled shells, high species and genera diversity and belong to the family Rotaliporidae (Cenomanian), families Globotruncanidae, Globotruncanellidae (Turonian–Maastrichtian). Benthic foraminifera belong mainly to genera Caudammina, Tritaxia, Dorothia, Marssonella Eponides, Reussella. The Upper Cretaceous deposits of the Ukrainian segment of the Pieniny Klippen Belt correspond to the sediments of the Czorsztyn sequence of its Polish segment, and were accumulated in the Czorsztyn submerged ridge (probably on its slope) located in the Alpine Tethys Ocean. The Upper Cretaceous deposits of the Marmarosh Klippen Zone were accumulated on the foot (Turonian – Santonian) and slope (uppermost Santonian – Campanian) of the another uplift such as the edge of the ancient Tisza-Dacia microcontinent, of which the Marmarosh Crystalline Massif is a part. Maastrichnian clastic sediments of the Jarmuta Formation were formed in the orogenic environments.