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Planktonic foraminifera are one of the most stratigraphically important groups of organisms for the Cretaceous system. However, standard foraminiferal zonations based mostly on species from the Tethyan bioprovince are hardly applicable in temperate regions where warm-water taxa are scarce or lacking. We propose a foraminiferal zonation based on foraminiferal events recognized in the northern Foraminiferal Transitional Bioprovince, which likely has a high correlation potential at least at a regional scale. Fifteen planktonic foraminiferal zones are distinguished from the upper Albian up to the uppermost Maastrichtian strata in extra-Carpathian Poland and western Ukraine. From the bottom to the top, Thalmanninella appenninica, Th. globotruncanoides, Th. reicheli, Rotalipora cushmani, Whiteinella archaeocretacea, Helvetoglobotruncana helvetica, Marginotruncana coronata, M. sinuosa, Pseudotextularia nuttalli, Globotruncana linneiana, G. arca, Contusotruncana plummerae, Rugoglobigerina pennyi, Globotruncanella petaloidea and Guembelitria cretacea. These zones are calibrated by macrofaunal zonations. [ABSTRACT FROM AUTHOR]

Abstract: The Maastrichtian was a time of a high variability in the climate/ocean system. Most studies on Maastrichtian palaeoenvironment fluxes have been based on evidence from the open ocean realm or from outcrops in the Tethyan realm. We have investigated epicontinental carbonate-rich sediments of Maastrichtian age of the Lublin-Lviv Syncline (SE Poland and western Ukraine). Our study is focused on the population changes of planktonic foraminifers from 21 Maastrichtian outcrop successions and one borehole section. Quantitative and qualitative studies of planktonic foraminifers show long-term foraminiferal changes that make it possible to reconstruct climatic changes and a sea-level curve for the latest Campanian and Maastrichtian from the high-latitude epicontinental sea. A significant regression is inferred for the latest Campanian and earliest Maastrichtian. The highest sea level is noted in the earliest Late Maastrichtian. It coincides with a migration of the benthic and planktonic foraminiferal fauna that was probably triggered by a cooling episode. The cooler episodes correlated with a eustatic sea-level highstand during that time, suggesting that sea level was the most likely mechanism causing a change of global circulation; this temperature drop could be the cause of the mid-Maastrichtian event. [Copyright &y& Elsevier]

Earlier studies of individual fluid inclusions in salt minerals of some Devonian evaporite basins showed that the brines in those basins were of chloride type with a high concentration of Ca2+. The genetic significance of this occurrence was subject to different interpretations. We have studied in detail samples taken from the East European Dnipro-Donets and Prypiac' evaporite basins aiming to establish the chemical composition of fluid inclusions in studied evaporites and then, using other geochemical information, to establish a geochemical model of the Devonian evaporite basins. Our study showed that salt deposition in the Devonian Dnipro-Donets and Prypiac' evaporite basins was because of intensive evaporation of mainly marine brines of chloride type with a relatively high Ca2+ content. In turn, the ratios between Na, K, and Mg corresponded to ratios in recent marine brines. Salt minerals precipitated in bottom water conditions. The occurrence of one-phase fluid inclusions indicates the temperatures of halite- precipitating brines <43°C. Gas content varied from 10 to 300 g/L and was controlled by the pressures existing at the basin bottom during halite growth. The recorded high Ca2+ contents, characteristic of brines in the Dnipro-Donets rift basin, is due to intensive discharge of connate highly mineralized Ca2+-rich solutions; however, the parent marine water was also Ca2+ rich. [ABSTRACT FROM AUTHOR]

In the middle Miocene Badenian gypsum basin of the Carpathian Foredeep, west Ukraine, three main zones of gypsum development occur in the peripheral parts of the basin. Zone I consists entirely of stromatolitic gypsum formed in a nearshore zone. Zone II is located more basinward and is characterized by stromatolitic gypsum in the lower part of the section, overlain by a sabre gypsum unit. Zone III occurs in still more basinward areas and is characterized by giant gypsum intergrowths (or secondary nodular gypsum pseudomorphs of these) in the lowermost part, overlain by stromatolitic gypsum, sabre gypsum and then by clastic gypsum units. Correlation between these facies and zones has been achieved using lithological marker beds and surfaces. Of particular importance for correlation is a characteristic marker bed (usually 20–40 cm thick) of cryptocrystalline massive gypsum occurring in zones II and III. The marker was not distinguished in zone I, possibly because this bed is older than the entire gypsum section of that zone. These new results strongly suggest that the deposition of giant gypsum intergrowth facies and stromatolitic gypsum facies was coeval. In some sections of zones I and II, limestone intercalations have been recorded within the upper part of the gypsum sections. Considerable scatter of the δ18O and δ13C values of these limestones indicates variable diagenetic overprints of marine carbonates, but a marine provenance of the limestones is confirmed by microfacies analysis. Some of the limestones are coeval with an intercalation of gypsarenitic, mostly laminated gypsum occurring in the sabre gypsum unit of zones II and III. Badenian gypsum formed in extremely shallow-water to subaerial environments on broad, very low relief areas of negligible brine depth, which could be affected by rapid transgressions. Stable isotope (δ34S, δ18O) studies of the gypsum demonstrate that the... [ABSTRACT FROM AUTHOR]

Primary gypsum is the main evaporite mineral in the middle Miocene (Badenian) of the West Ukraine. The lower part of the gypsum sequence is built of autochthonous gypsum while the upper part is composed of allochthonous gypsum that formed following a major, tectonically induced, change in basin morphology. This change resulted in the destruction of the gypsum deposited on the margins of the basin and formation of redeposition features. Autochthonous gypsum facies were deposited in two main environments: (1) giant gypsum intergrowths precipitated from highly concentrated brines; (2) very shallow subaqueous gypsum deposited in a vast brine pan. The brine pan was characterized by a facies mosaic that reflects an interplay of concentrated brines from the central part of the evaporite basin and diluted brines due to the influx of continental meteoric waters. The facies continuum, microbial gypsum-bedded selenite -- massive selenite -- sabre gypsum, indicates increasing salinity of the brine with time. This type of facies pattern has been established in recent salines that are analogous to Badenian gypsun in their lateral facies changes However, the pattern of facies distribution with respect to the open sea in the Badenian basin is opposite to that found in recent salinas. The pattern of the Badenian gypsum facies in the Ukraine indicates that facies repetition may have been related to climatically controlled salinity changes and not to depth changes, as is commonly used to explain the repetition of sulphate facies in a vertical succession. [ABSTRACT FROM AUTHOR]