Zofia Dubicka

The Lower/Upper Maastrichtian boundary interval in the Lublin Syncline (SE Poland, Boreal realm): new insight into foraminiferal stratigraphy

A detailed micropaleontological study of the upper part of the Lower and Upper Maastrichtian strata of the Lublin Syncline (SE Poland) recorded several foraminiferal events and foraminiferal event stratigraphy turned out to be useful for interregional correlation. Main foraminiferal events recorded are: the temporary disappearance of Rugoglobigerina spp. coinciding with the last occurrence of Angulogavelinella gracilis; the reappearance of Globotruncana spp. after a longer absence in the area; the temporary disappear ance of Stensioeina spp. and the last occurrence of Gavelinella monterelensis, as well as a short-lived bloom of Globotruncanella petaloidea. The reappearance of Globotruncanidae in SE Poland slightly above the base of the Belemnitella junior Zone probably reflects a global sea level rise recognised in north-western Europe and eastern North America. The temporary disappearance of the genus Rugoglobigerina at the base of the Belemnitella junior Zone may be used as a good marker for the Lower/Upper Maastrichtian substage boundary in the Boreal Province.

Foraminiferal record in a condensed marine succession: a case study from the Albian and Cenomanian (mid-Cretaceous) of Annopol, Poland

A condensed succession at Annopol is of key importance for the mid-Cretaceous palaeontology and palaeobiogeography in Poland. Here, the planktonic and benthic foraminifera from the Albian and Cenomanian intervals are studied. The local foraminiferal record is strongly influenced by burrowers. On the one hand, piping down of the foraminiferal tests through burrows disturbed the original succession, for example by introduction of the Cenomanian foraminifera into the Albian phosphorite horizon. On the other hand, the foraminifera in the burrow fills near the base of the Cenomanian provide the sole piece of evidence of a lower upper Cenomanian unit lost from the record by erosion. Changes in foraminiferal assemblages allow for the interpretation of the succession in terms of bathymetry and biological productivity. The highest rate of primary production is deduced for the Albian phosphorite horizon. Integration of foraminiferal and ammonite biostratigraphy with sedimentology allows for the comparison of a pattern of sea-level oscillations recorded at Annopol with the relevant portion of the classic graph of sea-level changes for the British Isles. It turns out that all important elements of the British curve, that is, transgressive peaks and regressive troughs or lows, left their distinctive, albeit highly residual, record in the Annopol succession. This study demonstrates that even extremely condensed marine deposits, such as those at Annopol, may provide a foraminiferal record of better quality, order and resolution than conventionally anticipated.

Unlocking the biomineralization style and affinity of Paleozoic fusulinid foraminifera

Fusulinids are the most diverse, abundant and geographically widespread Paleozoic foraminifera which are widely considered to possess a “homogeneously microgranular” test microstructure composed of subangular grains of several micrometers in size. However, this texture appears to be a diagenetic artifact. Here we describe well-preserved Devonian calcareous fusulinids (Nanicella) from the Holy Cross Mountains (HCM) in central Poland. Foraminifera from Poland in which the primary nature of tests have not been masked by diagenesis are composed of low magnesium calcite spherical grains up to about 100 nanometers in diameter, identical to those observed in Recent and fossil hyaline foraminifera (Rotaliida, Globothalamea). These data call the paradigm of microgranular test microstructure of Foraminifera into question, and suggest a possible phylogenetic relationship between globothalamids and some fusulinids.

Foraminiferal, ostracod, and calcareous nannofossil biostratigraphy of the latest Badenian – Sarmatian interval (Middle Miocene, Paratethys) from Poland, Romania and the Republic of Moldova

Abstract This study presents detailed foraminiferal, ostracod, and calcareous nannofossil analyses of five Middle Miocene sections located in the Central Paratethyan realm, namely in Poland, Romania and the Republic of Moldova. Based on foraminiferal distribution, five biostratigraphically important assemblages (labelled A-E) are distinguished. Foraminifera data combined with ostracoda and nannofossil evidence allowed correlation between the studied sections, and a comparison with the deposits of similar age from the Transylvanian, Vienna and Pannonian basins, as well as with the Transcarpathian regions. The micropaleontological record across the Badenian-Sarmatian boundary interval is also presented.