Otwornice warstw krośnieńskich w pobliżu V-tego horyzontu tufowego w Radziszowie (polskie Karpaty zewnętrzne)

Abstract

 Przedstawiono zespół małych otwornic występujących w pobliżu V-tego horyzontu tufowego serii menilitowo-krośnieńskiej w polskich Karpatach zewnętrznych. Stwierdzono, że badany zespół składem gatunkowym odpowiada zespołom otwornic z warstw polanickich i krośnieńskich górnych Karpat ukraińskich.

FORAMINIFERS FOUND NEAR THE TUFF HORIZON V IN THE KROSNO BEDS AT RADZISZÓW (POLISH OUTER CARPATHIANS)

Seven correlational tuff horizons were differentiated in rocks of the Menilite-Krosno Series in the Polish Outer Carpathians. For some of these horizons (V–VII), there were made radiometric datings.

The datings, made on zircons recorded in these horizons: 20.5, 19.8 and 15.6 m.y., suggest that sedimentation of upper part of the Menilite-Krosno series was proceeding already in the Miocene (T. Wieser, 1979). Recently, an impoverished foraminifer assemblage has been found in rocks occurring near the tuff horizon V, dated at 20.5 m.y. The most characteristic species of that assemblage, Turborotalia siakensis (Le Roy), indicates that the assemblage may be not older than the Upper Oligocene.

The studied foraminifer assemblage corresponds to microfauna from the Polanica and Upper Krosno Beds in the Ukrainian Carpathians. The age of the Polanica Beds is still not unequivocally established but it falls within the Upper Oligocene - Lower Miocene interval.