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The Sokoliska Limestone, a new regional marker horizon of coccolith laminites in the Oligocene of the Outer Carpathians : diagnostic features and stratigraphic position

Ciurej A., Haczewski G.

Annales Societatis Geologorum Poloniae

2016

Vol. 86, No. 4

415--427

Isochronous horizons of pelagic coccolith limestones are important regional stratigraphic markers in the Oligocene sequences of the Outer Carpathians. Three widely recognized limestone horizons are the Tylawa Limestones, the Jasło Limestone and the Zagórz Limestone horizons. Another regional marker horizon is described here, the Sokoliska Limestone horizon, situated between the Jasło Limestone and Zagórz Limestone horizons in the nannoplankton NP24 Zone. Its lithologic characteristics allow it to be distinguished from the other limestones, especially under the optical microscope. Its dark laminae are greatly enriched in non-calcareous material. The limestone contains tests of planktonic foraminifers, but these are much less abundant than in the Jasło Limestone. The boundaries with the marly shales above and below are often more gradational than is the case with the other limestone horizons.The Sokoliska Limestone has been recognized over a distance of ca.550 km in the Skole (Tarcãu) and Silesian units of the eastern and northern parts of the Outer Carpathians. Four sections of the Sokoliska Limestone horizonin the Polish and Romanian Carpathians are described; the exposure in the Sokoliska cliff of the Solinka River at Bukowiec was selected as the reference locality.

The Tylawa Limestones – a regional marker horizon in the Lower Oligocene of the Paratethys : diagnostic characteristics from the type area

Ciurej A., Haczewski G.

Geological Quarterly

2012

Vol. 56, No. 4

833-–844

Three units of laminated coccolith limestone are used as regional chronohorizons in the Oligocene of the Outer Carpathians. Two of them – the Tylawa Limestones and the Jasło Limestone display a similar type of lamination and their discrimination is in some cases problematic. We provide a detailed mesoscopic and microscopic lithological description of the Tylawa Limestones from the type locality at Tylawa and from Rudawka Rymanowska – the best exposure in the Polish Carpathians. The finely laminated limestone layers are up to 5.5 cm thick and are dispersed through a section more than 100 m thick. They are grouped in clusters. They differ from the younger Jasło Limestone in: (1) an absence of foraminifers, (2) a mass occurrence of Reticulofenestra ornata Müller, (3) the presence of voids after pennate diatoms, (4) dark laminae which are more pronounced than in the Jasło Limestone.