Commune: Żywiec (pow. żywiecki, woj. śląskie)
Framework element or context represented:
The lowermost part of the Silesian Unit succession in the Western Carpathians.
Primary geological/geomorphological interest:
The Lower Creatceous deposits of the Silesian Unit.
Comparative assessment justification:
The full developed profile of the Lower Cretaceous deposits with sills of teschenite. Exeptional natural outcrops in the Polish Carpathians.
Protection status and accessibility:
Proposed to protection as documentary site; outcrops are well accessible during the low water level.
Character of site: Natural outcrops.
Area: 2 ha
Altitude: 365 m a.s.l.
Lithology: conglomerates, breccias, limestones, shales
Discipline: Petrography, Stratigraphy of Phanerozoic, Tectonics
Process Age: *all periods
Bedrock Age: Cretaceous, *all periods
Description of primary interest:
The area of Grojec hill in Żywiec is one of the most interesting and controversial geologic elements in the Żywiec Basin. On the right bank of the Soła river, upstream the Koszarawa mouth, a 200 m long, continuous profile of the Lower Cretaceous deposits of the Silesian Unit is visible. Because of numerous scales and strong folding of shale deposits of the Cieszyn-Grodzisko series geologic pattern is disputable. Here, the oldest deposits of the Silesian Unit are the Cieszyn limestones, representing the upper (Cretaceous) part of this member. Limestones are the main constituents of the first outcrop. They comprise about 400 calciturbidites of various thickness). Between the limestones, forming here a small anticline, two teschenite sills occur which are a subject of paleomagnetic studies. Further, about 800 m south of the Koszarawa mouth there is an outcrop of a thick rock complex consisting of Cieszyn-Grodzisko series. These series form a larger anticline in the core of which there are variegated shales belonging to the window series. A layer of a sedimentary breccia, 21 m thick, as a megaturbidite is a characteristic element of the discussed exposure. This breccia layer contains, besides size-differentiated clasts representing all members of the Cieszyn series, larger patches reaching up to 3 m in length. They represent, among others, dark grey, almost black, clayey shales with fine-grain siderite sandstone lamina resembling Wierzowa shales. There are also visible patches of Cieszyn limestones. Among these rocks, strongly weathered teschenite blocks and fine- and medium-bedded sandstones with carbon chunks, representing the Grodzisko beds occur.
Literature:
ALEXANDROWICZ Z., POPRAWA D., RĄCZKOWSKI W. 1999–Stratotypes and other important geosites of the Polish Carpathians. Pol. Geol. Inst. Special Papers 2: 33-46. GRABOWSKI J. KRZEMIŃSKI L., NESCIERUK P., PASZKOWSKI M., SZYDŁO A., PÉCSKAY Z., WÓJTOWICZ A. 2004–New data on the age of teschenitic rocks (Outer Carpathians, Silesian Unit) - results of the K-Ar dating. Przegląd Geolog. 52, 1: 40-46. GRABOWSKI J., NAWROCKI J., NESCIERUK P., WÓJCIK A., OLSZEWSKA B. 1996–Wycieczka A4. In: D. Poprawa, W. Rączkowski (eds) (in Polish only) - Przewod. 67 Zjazdu Pol. Tow. Geol.: 73-85. Szczyrk. MALIK K. 1994–Przejawy wielkoskalowej resedymentacji w najstarszych osadach fliszu karpackiego (in Polish only). In: III Krajowe Spotkanie Sedymentologów. Mater.: 50-55. Sosnowiec. NOWAK J. 1970–Spostrzeżenia nad Calpionell alpina Lor. I Calpionell elliptica Cad. (Tintinnida) z wapieni cieszyńskich Śląska Cieszyńskiego (in Polish only). Kwart. Geol. 14, 4: 907-909. NOWAK J. 1970–Zagadnienie litologicznej i stratygraficznej korelacji wapieni cieszyńskich na obszarze Kotliny Żywieckiej (in Polish only). Kwart. Geol. 14, 4: 916-917.