Neogen niecki orawsko-nowotarskiej

Abstract

THE NEOGENE OF THE ORAWA - NOWYTARGBASINSummaryThe Orawa –NowyTargBasin, stretching from Czorsztyn in the east to Namiestów in the west, forms a belt which measures62 kmin length. It is filled entirely with fresh-water and continental sediments which have been deposited there from the Upper Oligocene, throughout the whole Neogene and Quaternary, till present.In this intramountainous basin, where the bottom was usually subsiding while the surrounding mountains were elevated, a complex of rocks, about1 300 mthick, was formed during the Neogene. The following subdivision of these rocks is based on gastropod fauna described by E. Woźny (1970): Czarny Dunajec Beds (Chattian-Aquitanian-Burdigalian), 190–430 m thick; Orawa Beds (Helvetian-Tortonian),124–300 m thick; Koniówka Beds (Sarmatian), 130–180 m thick; and Podczerwone Beds(Lower and Middle Pilocene), 14–240 m thick. In addition, the Mizerna Beds (Upper Pliocene), 6–150 m thick, have been distinguished on the basis of flora (W. Szafer, 1954; J. Oszast, 1973).The Neogene deposits were formed as a result of the accumulation of clastic material in alluvial fans, among which marshy lakes were formed in places. These deposits represent the type of sedimentation which is characteristic of fractionated cyclothems in alluvial deposits. They begin with sediments of the slowly flowing waters (pebbles, gravels, coarse-grained sand); sediments of the more slowly flowing waters come next (medium to fine-grained sand), followed by those of stagnant waters (dust and clay).The petrographic composition of theLower Miocendeposits in the northern part of the Basin shows the predominance of the Magura material. Material of the Podhale Flysch and of the Klippen Belt prevails in the Middle Miocene to Lower Pliocene deposits of the southern part of the Basin.The Neogene deposits described here formed a syncline, locally with undulations, intersected by faults. Deposits which are older than the Middle Pliocene are the most strongly disturbed. No disturbances were observed in Upper Pliocene deposits.