Budowa geologiczna góry Krzemianki koło Kielc

Abstract

Przedstawiono profil litologiczny i sytuację tektoniczną warstw kambryjskich odsłoniętych przekopem drogowym na górze Krzemiance. Autorzy stwierdzili tu obecność fałdu obalonego ku SW z płaszczyzną osiową pochyloną ku NE. Fakty zarejestrowane na górze Krzemiance w zestawieniu z wcześniejszymi obserwacjami z Wiśniówki i Wąworkowa pozwalają wyciągnąć wniosek o regionalnym charakterze tego typu deformacji plastycznych.GEOLOGICAL STRUCTURE OF KRZEMIANKA HILL NEAR KIELCE Lithologic section and observation on tectonics of Cambrian rocks exposed along road excavation traversing Krzemianka Hill (area north of Kielce) are discussed in the paper. The hill forms the last western elevation of the main range of the Świętokrzyskie Mts. Knowledge of lithology and tectonics of that part of the mountains was practically none till present. The authors distinguished the four Iithologic complexes: claystone, claystone-sandstone, quartzitic sandstone, and claystone-siltstone-sand-stone. A trench with its lithologic section, made in 1965 about 650 m north-west of the road excavation, was, included in the present study. There is a good correlation of both the exposures, since thickness of both quartzitic sandstone complexes occured to be almost equal. On the contrary, lithologic correlation of the Krzemianka Hill rocks and those of the Wiśniówka area has met serious difficulties at the present state of knowledge. The three complexes of quartzitic sandstones have been found within the Wiśniówka area, reprezentative exposures of which are located at Wiśniówka Wielka, Wiśniówka Mała, and Podlesie. Age of the southernmost sandstone complex at Podlesie has not been yet determined, thus its correlation with the sandstone complexes at Wiśniówka Wielka and Wiśniówka Mała as well as Krzemianka Hill is not feasible due to lack of competent data. The Cambrian rocks build the back of Krzemianka Hill in a form of synclinal fold overturned to south-west, with its axial plane dipping north-east. All the elements of the fold are clearly visible on the road excavation site: a down rank with its beds dipping north-east at an angle of 50 - 55 degrees, a crest with drag fold well developed, and an upper flank with beds dipping south-west at an angle of 55 degrees. The upper flank of the fold was only exposed in the trench, with its beds dipping north-east at an angle of 50 degrees. It is most likely that the structure under consideration forms the root element of a larger complex fan fold developed within the main range of the Świętokrzyskie Mountains. Consideration on tectonics of the area, presented in the paper, are closely consistent with observations of J. Czarnocki and J. Samsonowicz, formerly made in the Wiśniówka and Wąworków area. Against such a background an assumption may be put forward for consideration that analogous tectonic phenomena play important part on regional scale.