Browsing by Author "Strzelecki, Piotr Jan"

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Access status: Open Access ,
Continuous contractional deformation followed by extension in the Nowy Sącz Basin, Polish Outer Carpathians: constraints from fault-slip analysis
(Wydawnictwa AGH, 2025) Fodor, László; Świerczewska, Anna; Strzelecki, Piotr Jan
Fault-slip analysis was carried out in the Nowy Sącz Basin and the surroundings of the Polish Outer Carpathians based on field observations, published maps, and publications. A reconstruction of the stress field and the contractional directions from the folds suggests that the area was marked by four different deformation phases, most of them involving several stress states. The tilt test supports the separation of pre-, syn-, and post-folding deformation episodes within the phases which occurred during the folding of the Palaeogene to Early Miocene flysch units and also during the folding of the late Middle Miocene basin fill. After an early extensional phase at the onset of the deformation history, the area was marked by contractional deformation from ~34 Ma to ~8 Ma. During this period the compressional direction did not change markedly but a slight clockwise change of the maximal stress axis may have occurred in the Early Miocene due to vertical-axis block rotation. In this persistent deformation field, the basin could have had a contractional origin in front of an out-of-sequence thrust. The latest Miocene(?) to Quaternary deformation was probably related to the extensional collapse of the Carpathian accretionary wedge.
Access status: Open Access ,
Fractured clasts in the Mt Currie Conglomerate at Kata Tjuta (Central Australia): evidence of Early Cambrian earthquakes?
(Wydawnictwa AGH, 2020) Tokarski, Antek K.; Strzelecki, Piotr Jan
Lower Cambrian Mt Currie conglomerate at Kata Tjuta bornhardts (Central Australia) bears numerous fractured clasts. Clast-cutting fractures are restricted to particular clasts, the matrix of the conglomerate is not fractured. The fractures are tectonic joints of two sets. The joints were formed due to either seismic or aseismic deformation. In the former case, the fractures may result from Early Paleozoic earthquakes.
Access status: Open Access ,
The provenance of erratic pebbles from a till in the vicinity of the city of Radom, central Poland
(Wydawnictwa AGH, 2019) Strzelecki, Piotr Jan
Petrographic analysis, including the indicator erratics count method of coarse pebbles (20–60 mm), was performed for the first subsurface layer of the glacial till in the vicinity of the city of Radom. Crystalline rocks comprise 60% of the sample, whereas carbonate and clastic sedimentary rocks total 18% and 15%, respectively. Among the crystalline rocks, 14% clasts were identified as indicator erratics. The majority of the indictor erratics originated from the Åland region (63%). Significant contributions were also derived from the central Baltic Basin (12%), Ångermanland (9%) and Uppland (9%) regions. Trace amounts are recorded from the northern Baltic, Dalarna and Småland regions. The spatial distribution of crystalline erratic source areas suggests material incorporation into an ice sheet mainly from central-eastern Fennoscandia. The indicator assemblage composition indicates the Odranian (MIS 6) origin of the till. The majority of the erratic sedimentary rocks were derived from the central and southern Baltic Basin while local rocks comprise a minor proportion. The relatively low carbonate clasts content indicates that the till was affected by partial decalcification resulting from post-depositional chemical weathering. This study supplements the results on erratic pebble provenance in the glacial tills of Middle Polish Glaciation Complex in Poland.