Genus Silicoplacentina (Class Amoebina) from the Miocene Machów Formation (Krakowiec Clays) of the northern Carpathian Foredeep

Abstract

Representatives of the genus Silicoplacentina have been found in the Jamnica S-119 borehole and in an open pit at the Machow mine in the upper part of the Krakowiec Clays (Machów Formation). They represent the thecamoebians, which have not been previously described from the Polish part of the Carpathian Foredeep. Silicoplacentina species are accompanied by foraminifers of the genus Miliammina characteristic of the Pannonian, Sarmatian relict forms of the genera Quinqueloculina, Elphidium and Nonion, as well as fragments of fish, otoliths and ostracods. A Late Sarmatian foraminiferal assemblage of the Protelphidium subgranosum Zone, already known in earlier literature, occurs below the deposits with Silicoplacentina. Such a microfaunal succession may suggest that the microfossil assemblage found in the Jamnica S-119 borehole and Machów open pit comes from yet higher levels of the Krakowiec Clays than those previously described from the Protelphidium subgranosum Zone. A strong connection with microfauna from the Intra-Carpathian basins of the eastern Paratethys is marked in these youngest assemblages.