Stratygrafia płaszczowiny magurskiej w okolicach Piwnicznej

Hanna Ostrowicka


Lithostratigraphy of the Magura nappe in the vicinity of Piwniczna (Polish Flysch Carpathians)

In the vicinity of Piwniczna there are flysch formations which represent the so called Krynica facial zone of the Magura nappe, the highest nappe in the Polish Flysch Carpathians, These deposits are from Late Cretaceous to Eocene age. There have been distinguished in ascendent order the following lithostratigraphic units: Inoceramian beds, lower variegated shales (containing Hormosina and Rzehakina), Beloveza beds, Piwniczna sandstones, upper variegated shales (with Cyclammina amplectens Grzyb.) and Magura beds (Fig. 3). The main tectonic element of this territory is an anticline running NW—SE, its axial part is built of strongly deformed Inoceramian and Beloveza beds (Cretaceous and Paleocene) and in the limbs there are Piwniczna sandstones and Magura beds (Figs. 1, 2). Inoceramian beds are formed as thin bedded, shaly-sandstone flysch. The age of these deposits is Late Cretaceous (table 1). The lower variegated shales distinguish from the Inoceramian beds by the presence of shale intercalation red and/or green in colour. This unit is of Paleocene age (table 1). Beloveza beds is a rock complex in which thin bedded flysch prevails. Only minor intercalation of thick bedded sandstones and conglomerates are present in the Beloveza beds (so called Krynica conglomerates, Swidziński 1953, 1972). Beloveza beds are of Paleocene age (table 1). Piwniczna sandstones are represented by thick bedded sandstones similar to the overlying Magura sandstones. In the vicinity of Piwniczna these two deposits are separated by the upper variegated shales (Middle Eocene). Thick bedded sandstones (about 1000 metres thick) oceuring under Middle Eocene variegated shales have been distinguished as a separate unit and called Piwniczna sandstones. Magura beds are the youngest lithostratigraphic unit in this part of the Magura nappe. They are formed as thick bedded sandstones with secondary intercalation of shales. The southernmost facial zone of the Magura nappe — the Krynica facies — is characterized by the occurrence of deposits with considerable deal of thick bedded sandstones; they are noted already from Paleocene, where they are represented by the Krynica sandstones and conglomerates (Świdziński 1953, 1972, Ostrowicka 1965). In the Lower Eocene this type of sedimentation is strongly marked, not only in the Krynica zone (Piwniczna sandstones) but also in the Nowy Sącz zone farther to the north, in there it is pronounced by the presence of the upper Łącko beds (Węcławik 1969b). In the Middle Eocene and very probably in the Upper Eocene the thick bedded sandstones are the predominant type of deposits in the entire Magura basin.

Full Text: