Rozwój form osuwiskowych w Barnowcu (Beskid Sądecki, Karpaty zewnętrzne), w świetle analizy strukturalnych uwarunkowań osuwisk w Karpatach fliszowych

Abstract

DEVELOPMENT OF THE LANDSLIDE FORMS IN BARNOWIEC (BESKID SĄDECKI MTS, OUTER CARPATHIANS) IN THE LIGHT OF THE ANALYSIS OF STRUCTURAL BACKGROUND OF THE LANDSLIDES IN THE FLYSCH CARPATHIANS Summary Three structural landslides of different type are located in the Barnowiec Nature Reserve (Jaworzyna Krynicka Range, Outer Carpathians). Their development was connected with erosion initiated on the valley and valley head of Barnowski Stream. The area of landslides is located in Krynica Subunit of the Magura Nappe, built from thick bedded sandstones of Piwniczna Member (Magura Formation) underlained by thin bedded flysch of Zarzecze Formation with sandstones of Krynica Member. The development of the landslides was strongly related to geology of the region. The landslide occurring in the high part of the landslide zone in Piwniczna Sandstone Member, was created as a packet-rotary form consisting of long rocky packet system divided by the trenches. The niches and trenches developed as a saw-shape edge, created along two main crossing joint system (transversal). The second landslide (below) with rocky niche 50 m high, was developed in sandstone of Krynica Member as debris landslide with the big colluvial swell at the bottom. The rocky niche was created along many joint systems (longitudinal and transversal with disperssion of directions) and their shapes are complex (many-saw system). The niche of the third small landslide (debris-type) was developed as rocky wall along the one joint system. The detailed analysis of cutting and sliding surfaces of the landslide, and their relation to structural surface of the region, give the base to discussion about geological criteria of landslide classification. The study of Barnowiec landslides allows us to suppose, that all rocky Carpathians landslides should have a structural background, connected with the kind of initiation of mass movement.