Abstract:Tectonically deformed cave passages in the Tatra Mts (Central Western Carpathians) indicate some fault activity during the Quaternary. Displacements occur in the youngest passages of the caves indicating (based on previous U-series dating of speleothems) an Eemian or younger age for those faults, and so one tectonic stage. On the basis of stress analysis and geomorphological observations, two different mechanisms are proposed as responsible for the development of these displacements. The first mechanism concerns faults that are located above the valley bottom and at a short distance from the surface, with fault planes oriented sub-parallel to the slopes. The radial, horizontal extension and vertical σ 1 which is identical with gravity, indicate that these faults are the result of gravity sliding probably caused by relaxation after incision of valleys, and not directly from tectonic activity. The second mechanism is tilting of the Tatra Mts. The faults operated under WNW-ESE oriented extension with σ 1 plunging steeply toward the west. Such a stress field led to normal dip-slip or oblique-slip displacements. The faults are located under the valley bottom and/or opposite or oblique to the slopes. The process involved the pre-existing weakest planes in the rock complex: (i) in massive limestone mostly faults and fractures, (ii) in thin-bedded limestone mostly inter-bedding planes. Thin-bedded limestones dipping steeply to the south are of particular interest. Tilting toward the N caused the hanging walls to move under the massif and not toward the valley, proving that the cause of these movements was tectonic activity and not gravity.

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The SC-3 speleothem from Szczelina Chochołowska Cave, located in the Tatra Mountains, was studied in detail. U-series dating and age–depth modeling allowed us to constrain the period of speleothem growth to between approximately 330 and 200 ka, that is, during Marine Isotope Stages (MIS) 9–7. The complementary use of stable isotope analyses, petrographic studies, and trace element analyses allowed the identification of warm and wet climatic conditions that were favorable for speleothem growth during MIS 9e and MIS 9c. Unfavorable climatic periods included the cold glacial conditions of MIS 8 and the MIS 9/MIS 8 transition. The breaks in the growth of the SC-3 stalagmite were most likely connected with a reduction in precipitation in MIS 9a and extreme hydrologic events during MIS 8. Comparisons with other European records suggest that the climatic variability recorded in the speleothem from the Tatra Mountains is not only a record of local environmental conditions but can also be linked to European climatic patterns during both interglacial and glacial intervals. This makes our study the northernmost paleoclimatic record for the whole Carpathian range and one of the very few records from those periods worldwide.

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In the Central Western Carpathians (CWC), most published paleomagnetic results from Permo-Mesozoic rocks document extensive remagnetizations and come from thin-skinned thrust units that have undergone multistage deformation. We present results from lower Triassic redbeds from the autochthonous cover overlying the basement that carry a primary magnetization. Petromagnetic results indicate that the dominant ferromagnetic carrier is hematite, while magnetic susceptibility and its anisotropy are controlled by both ferromagnetic and paramagnetic minerals. Magnetic fabrics document weak deformation related to Late Cretaceous shortening. The directions of the high unblocking temperature remanence components pass both reversal and fold tests, attesting to their primary nature. Paleomagnetic inclinations are flatter than expected from reference datasets, suggesting small latitudinal separation between the CWC and stable Europe. Paleomagnetic declinations are mostly clustered within individual mountain massifs, implying their tectonic coherence. They show only minor differences between the massifs, indicating a lack of significant vertical-axis tectonic rotations within the studied central parts of the CWC. The paleomagnetic declinations are therefore representative of the whole of the CWC in terms of regional paleogeographic interpretations, and imply moderate counterclockwise rotations (c. 26°) of the region with respect to stable Europe since the Early Triassic.

A moment magnitude greater than M6.5 is needed to express a fault in topography (McCalpin & Nelson, 1996), and secondary effects such as landslides or liquefaction M > 5 are inevitable (Ambraseys, 1988; Keefer, 1984). Little or nothing remains in the geological record after a lower magnitude event, especially when both the morphology and deposits are remodeled by ice sheets or periglacial processes, as is the case in a majority of the Northern Hemisphere. In a tectonically stable part of Europe, despite the European Cenozoic Rift System (ECRS) crossing eastward from the Carpathians and westward from the North Sea (Špaček et al., 2015; Ziegler, 1992), singular events strong enough to produce fault ruptures have been recorded (e.g., Camelbeeck & Meghraoui, 1998; Štěpančíková et al., 2010, 2019). A prominent example of the tectonic structure of the ECRS is one of the most significant tectonic lines in Central Europe-the Sudetic Marginal Fault (SMF), which is approximately 200 km long. The NW-SE-trending fault bounds the Bohemian Massif to the north, as expressed by the 130-km long morphological step. Historical earthquakes along the SMF were not high intensities (I < 7 on the EMS intensity scale; Guterch, 2015). The minimum moment magnitude of prehistoric earthquakes has been estimated to be M6.3 (Štěpančíková et al., 2010), which theoretically can produce higher intensity earthquakes (I∼8.8 in the epicenter on the MSK intensity scale). According to the earthquake hazard map for Czechia, Poland, and Slovakia (Schenk et al., 2001), the Sudetes region's intensity should not exceed I = 6.5 (MSK). This reveals two issues: (1) earthquakes in the Sudetes region occurred in historic and prehistoric times, and (2) their intensities might not have been strong enough to have produced earthquake effects that were preservable in the geological record, especially since the landscape was remodeled by glacial and periglacial processes. However, cave environments are separated from external erosive factors and often favor preserving traces of past processes and events, after which marks on the surface are obliterated or covered.