Cenozoic deformation and stress field evolution of the Kozie chrbty Mountains and the western part of Hornád Depression (Central Western Carpathians)

Reconstruction of the Cenozoic palaeostress fields in the western part of Hornád Depression, south of Poprad town, was the main goal of the research. This was done on the basis of analysis of fault-slips. The most important was the detailed study of fault-slip kinematics. The deformation structures were measured and recorded in the Permian volcano-sedimentary sequence of the Malu iná Formation (Hronic Unit), and in the sequences of the Borové Formation, which is a basal part of the Central Carpathian Palaeogene Basin. The youngest measured rocks were the Lower Pleistocene travertines at the locality of Hranovnické pleso. An observed chronology of deformation phases can be divided into the seven different palaeostress fields. The oldest tectonic event (D1) was generated in terms of strike-slip tectonic regime with the W–E compression. This was recorded only in the Malu iná Formation, together with the second deformation stage. This performs strike-slip tectonic regime with the WNW–ESE compression (D2). Both deformations were conditionally included in the age between the Lower Palaeocene to Oligocene. The next, very distinct deformation event (D3) is represented by the NW–SE oriented compression in the strike-slip tectonic regime. This event includes the subset, which performs pure NE–SW tension (D3a) tenuously dated at the Early–Middle Miocene, because this phase also affected the Palaeogene sediments. The fourth generation of faults (D4) were activated during the Middle Miocene under strike-slip tectonic regime with N–S compression, in general. The age was determined relatively, because the deformation structures (D4) are cut by fault of the D5 stage. The fifth phase of deformation (D5) originated in strike-slip tectonic regime with the NE–SW direction of compression. The age of the deformation is considered to be the Late Miocene. The sixth deformation stage (D6) is characterized by the pure W–E extension. The stage was originated in the Quaternary age, because it was identified only in the Lower Pleistocene travertines, the same as the last, youngest tectonic phase. This phase consisted of NNW–SSE oriented tension (D7).