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Analysis of non-karst caves in the Flysch Carpathians confirms the connection between the tectonic evolution of this orogen and the initial phase of cave formation. The compressional-extensional regime during the tectonic stages of the evolution of the Carpathians is the foundation of subsequent gravitational stresses within the slopes, which brought about various deformations of rock massifs, producing diverse types of subsurface cavities – caves. Therefore, most caves that occur in the Carpathians, represent forms of the opening and widening of joints and stress zones originated much earlier. Classification based on the chronology and mechanisms of these caves is proposed. A chronological approach requires understanding the relationship of cave development to the stages of slope evolution and enables the construction of the morphogenetic classification, whereas consideration of the processes affecting the rock massif structure allows geomechanic classification. Using the morphogenetic criterion, three categories of caves can be distinguished: initial caves developed during slope deformations preceding the principal slope failures (landslides), subsequent caves formed during the main slope failure, and intermediate caves related to the main scarp formation. On the basis of the geomechanic criterion the following types of caves can be distinguished: dilational caves formed due to tensional fractures widening, dilatancy caves formed due to the fissure macrodilatancy, and boulder caves , which represent chaotic cavities. In order to illustrate this classification, type localities of the various cave types are presented. The radiocarbon dating of secondary formations (speleothems) occurring in the caves indicate that they initially formed in the Weichselian (Upper Plenivistulian), Late Glacial and Early Holocene and underwent various transformations. [ABSTRACT FROM AUTHOR]

Crevice-type caves, formed along joints, are very common in the Polish Flysch Carpathians (more than 600 have been recorded). The caves represent accessible parts of the widened cracks, which are basic, initial forms of development of deep-seated rock landslides. Structural features of four selected caves (situated in different parts of the Carpathians) were studied in order to determine relations between joint systems and landslide formation. The studies prove that the main rock scarps often represent effects of earlier propagation of the cracks (=cutting surfaces) due to loading and unloading shearing stress. The cracks are structural forms developed along joints or faults. The cutting surfaces represented by cracks (caves) develop a long time before the main gravitational mass movements, whereas the sliding surfaces (shearing zones) are formed or significantly modified ad hoc during the gravitational transport of rock masses. Occurrence of the deep initial cracks causes modification of shape of the sliding surfaces, which are noncircular. The mountain slopes cut by many cracks are permanently developed. Thus, the periodic increase of activity of external factors (floods, downpours, earthquakes, etc.) leads to common formation of the landslides earlier prepared by crack development. This model of slope evolution enables us to interpret the occurrence of the landslide phases (in the Holocene) during which increasing of frequency of the landslides is observed. [Copyright &y& Elsevier]

Abstract: Widened discontinuities (among them crevice-type caves) are characteristic phenomena of landslides in anisotropic rock massifs forming the Flysch Carpathians. We tested the reliability of 2D electrical resistivity tomography (ERT) in the detection of well-mapped cave passages and then tried to explore new subsurface cavities in three sites of crevice-type caves in the Polish Flysch Carpathians: the Jaskinia Miecharska, Jaskinia Malinowska and Jaskinia Diabla Dziura caves; each comprising a different stage of mass-movement development and thus being a representative case study. The total of 14 ERT profiles was selected, while each of them was measured by several electrode arrays (dipole–dipole, Wenner and/or Wenner–Schlumberger). Our results show that the selection of an appropriate electrode array and spacing are crucial for the detection of subsurface cavities. Measurement using the dipole–dipole electrode array gave best results in the detection of known structures and its interpretation seems to be most reliable in the extrapolation of non-investigated areas. The application of ERT shows abundant occurrence of air-filled voids in gravitationally deformed flysch massifs and in several places its results enable comparison with open spaces detected by speleological exploration. ERT enables us to identify fractures in deformed slopes before the proper failure of these slopes affected by a landslide as well as in landslides themselves: fissure zones connected with trenches, less dense segments of colluvial ramparts and some lithological-tectonical or gravitationally induced elements of slope structures. The reliability of ERT detection of potential caves was verified by speleological exploration of a newly discovered cave at the Jaskinia Miecharska site following the ERT campaign. [ABSTRACT FROM AUTHOR]