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2 2020

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Strukturalne, litologiczne oraz tektoniczne uwarunkowania rozwoju i ewolucji świętokrzyskich skałek piaskowcowych

Urban Jan

Przegląd Geologiczny

2020

vol. 68, nr 2

112--126

Majority of ca. 90 sites ofsandstone crag groups and individual crags, occurring in the Świętokrzyskie (Holy Cross) Mts. region, represent the following crag-forming lithostratigraphic units: Cambrian Wiśniówka Formation, Devonian Barcza Fm and Zagórze Fm, Triassic Zagnańsk Fm and Krynki Beds, as well as Jurassic Skloby Fm and Ostrowiec Fm. Specific features of these rocks are the occurrence of sandstone series, up to 20 m thick, above more plastic, clayey or heterolithic series, high-energy depositional environments, and siliceous composition. The crag-forming sandstones differ in the amount of siliceous cement: from strongly cemented Paleozoic quartzitic sandstones to porous Mesozoic sandstones with poor cement, which determines diverse mechanical properties. Strongly cemented Paleozoic rocks display high rock strength and abrasion resistance, while porous and theoretically friable Mesozoic sandstones are characterised by high grain packing due to compaction. Regarding the principal role of gravitational disinte¬gration of rock massifs under the periglacial conditions in the Pleistocene, other factors constraining the crag formation and shaping are the tectonic situation of rocks (orientation of strata and joints), adequate joint spacing, and bed thickness. The interrelations between lithological and structural features of crag-forming sandstones and tectonics, conditioning erosion and weathering rates are specific for particular types of these sandstones.

Rzeźba strukturalna obszaru Świętokrzyskiego Parku Narodowego

Łajczak Adam, Urban Jan, Rączkowska Zofia, Wałach Grzegorz

Przegląd Geologiczny

2020

vol. 68, nr 2

102--111

The area of the Świętokrzyski National Park is one of the most evident examples of structural morphology in Poland. Its relief is clearly determined by bedrock lithology: the hill ranges are composed of hard quartzitic sandstones of the upper Cambrian (Łysogóry Range) and the Lower Devonian (Klonowskie Range), while the depressions, usually vast and flat-bottomed, are distributed on outcrops of soft, easily weathered and eroded Ordovician and Silurian shales, greywackes and sandstones. The parallel pattern of hill ranges and depressions, as well as a mesh-grid pattern of river valley systems and the antecedent character of river gaps, reflects fold tectonics modified by transverse faults. Such a morphology developed during the Paleogene and Neogene under hot and then warm, gradually cooling climatic conditions. In the Pleistocene, principally under the periglacial conditions, block fields (symbols of the Świętokrzyski NP) and crags (crests, table-like forms, cupolas and spurs) were formed. The shape and spatial position of most crags are related to geological structures.