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Pararotalia aculeata (d.Orbigny, 1846) ze środkowego miocenu Paratetydy Centralnej

Szczechura J.

Przegląd Geologiczny

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2004

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Vol. 52, nr 1

76-79

EN

The foraminifers belonging to the genus Pararotalia Le Calvez from the Middle Miocene of the Central Paratethys are referred to different species, eg. Pararotalia (or Rotalia) stellata (Łuczkowska, 1955; Śmigielska, 1957; Urbaniak, 1974; Szczechura, & Pisera 1986) and P. ex gr. lithothamnica (Oszczypko et al., 1992) from Poland, P. stellata from Slovakia (Holcová et al., 1996), Rotalia calcar from Hungary (Korecz-Laky & Nagy-Gellai, 1985) and Pararotalia aculeata, P. cf. aculeata as well as P. spinimargo from Romania (Popescu, 1979). It is suggested here, that all of them represent one species, ie. Pararotalia aculeata (d’Orbigny, 1846). The large infraspecific variability of this species (Pl.1, figs. 1–19), resulting in its taxonomic spliting, seems to be a consequence of ontogenetic changes, ecological modifications as well as different state of preservation. The systematic relation between P. aculeata and other so far known representatives of Pararotalia, especially those from the Neogene of theMediterranean areas, should be based on large comparative material, however P. padana Mancin, Pirini et Lanfrancini, 2000, from Pliocene of Italy, seems to be conspecific with the here discussed species.

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Ostracoda of the Eemian Interglacial at Kruklanki in NE Poland

Namiotko T., Szczechura J., Namiotko L.

Studia Quaternaria

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2003

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Vol. 20

3-24

EN

The assemblage of lacustrine ostracods found in the Eemian Interglacial sediments at Kruklanki (Masurian Lake District, northeastern Poland) contains 18 species belonging to 13 genera. The most dominant species are Candona neglecta Sars, 1887, Limnocytherina sanctipatricii (Brady et Robertson, 1869), Limnocythere inopinata (Baird, 1843) and Candona candida (O.F. Müller, 1776). Cyclocypris serena (Koch, 1838), Ilyocypris decipiens Masi, 1905, Pseudocandona insculpta (G.W. Müller, 1900) and Leucocythere mirabilis Kaufmann, 1892 are recorded for the first time from the Eemian of Poland; the latter two species are also new for the Eemian lacustrine deposits of Europe. The ecological requirements of the recognised ostracod species as well as their geographic ranges in the Quaternary of Europe are summarised. Based on these data, past habitat type is estimated as a deeper littoral of a lake with reasonably cold, well-oxygenated and calcium-rich waters. The present state of knowledge of the Eemian ostracods from Poland is reviewed and their comparison with the Eemian ostracod assemblages from Europe is briefly given. Comparison of the ostracod faunal assemblage from Kruklanki with those from other Eemian sites in Poland enables to establish and describe one general type of ostracod assemblages characteristic for lacustrine littoral in this interglacial.

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Palaeoenvironments of the Middle Miocene evaporite-bearing deposits from the Działoszyce Trough, Carpathian Foredeep, Poland, based on microfaunal studies

Szczechura J.

Geological Quarterly

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2000

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Vol. 44, Nr 2

119-135

EN

Analysis of microfossil distribution (foraminifera, ostracodes and bolboforms) in evaporite-bearing deposits from the Działoszyce Trough (northern Carpathian Foredeep) has allowed the distinction of three ecozones: the Globigerinoides ecozone (Lower Badenian), the Globigerina ecozone (Middle and Upper Badenian) including an evaporitic horizon, and the Anomalinoides dividens ecozone (Sarmatian). These ecozones are of ecostratigraphical significance and reflect major sea-level changes. The highest stands of sea-level correspond with the Globigerinoides ecozone and the upper part of the Globigerina ecozone, above the evaporites, and they are considered to relate to an influx of oceanic waters. Drastic climatic changes (cooling) and a sea-level fall that weakened bottom water circulation at the boundary between the Globigerinoides and Globigerina ecozones are considered the major factors which accounted for hypoxia (an oxygen-poor environment) that accompanied evaporitic deposition. The appearance of a specific ostracod assemblage (Xylocythere carpathica Szczechura and Microxestoleberis sp.) in Upper Badenian deposits is linked with the occurrence of active submarine hydrocarbon seepages.

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Age and evolution of depositional environments of the supra-evaporitic deposits in the northern, marginal part of the Carpathian Foredeep: micropalaeontological evidence

Szczechura J.

Geological Quarterly

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2000

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Vol. 44, Nr 1

81-100

EN

A rich assemblage of microfossils, including foraminifera, ostracodes and bolboforms (calcareous phytoplankton) have been found in the supra-evaporitic deposits of the Pecten Beds (Upper Badenian) and Krakowiec Clays (Sarmatian) of Middle-Miocene age, which occur in the Jamnica S-119 borehole near Tarnobrzeg, in the central part of the Carpathian Foredeep. Environmental conditions have been deduced from these microfossils. Comparison with other parts of the Carpathian Foredeep shows that microfauna distribution depended on location within the sedimentary basin and on hydrological conditions. Poorly-diversified and specific microfossils were associated with evaporites and overlying sediments (particularly within the lower Pecten Beds and Krakowiec Clays), indicating poorly-oxygenated near-bottom waters. Possibly, "Upper-Badenian" and "Sarmatian" biofacies had already differentiated by the end of the Badenian. Distribution of the Upper Badenian microfauna and bolboforms in the Polish part of the Carpathian Foredeep and beyond shows that there was faunal exchange between the eastern and western parts of the Polish section of the Carpathian Foredeep, and indicates connection between the Central Paratethys and Mediterranean basin areas.