THE ROPIANKA FORMATION OF THE BYSTRICA ZONE (MAGURA NAPPE, OUTER CARPATHIANS): PROPOSAL FOR A NEW REFERENCE SECTION IN NORTHWESTERN ORAVA

摘要

The thin- and medium-bedded, turbiditic deposits that are exposed in the Bystrica Zone of the Magura Nappe in the Slovak Orava region are the subject of this study. On the basis of lithological features as well as age and stratigraphic position, they are assigned to the Ropianka Formation. The very well exposed rocks of this formation, recognized in the Biela Farma profile in the Slovak part of the northwestern Orava region, are compared with analogous deposits in the Polish Orava and the Beskid Wysoki Mountains. Lithological and biostratigraphical documentation of the Ropianka Formation is presented. This documentation allowed the determination of the age of the rocks studied. Abundant and taxonomically diverse foraminiferal assemblages of agglutinated, benthonic and occasional planktonic forms indicate a Middle Paleocene age for the upper part of the Ropianka Fm. A new stratigraphic position for the Szczawina Sandstone, considered to be a member of the Ropianka Fm, is proposed. The lithostratigraphy of the Ropianka Fm in the Magura Nappe in Poland, Slovakia and the Czech Republic requires further investigation, including the establishment of new type and reference sections. The large outcrop at Biela Farma should be taken into consideration as a potential reference section. Studies of the new sections will lead to a new monographic elaboration of the Ropianka Fm in Poland, Slovakia and the Czech Republic.