Commune: Krzeszowice (pow. krakowski, woj. małopolskie)
Framework element or context represented:
Permian volcanic rocks.
Primary geological/geomorphological interest:
Lower Permian porphyry covered by Lower Triassic marine deposits.
Comparative assessment justification:
In the Cracow Upland the described quarry is one and only outcrop of Lower Triassic marine deposits covering the Permian volcanic rocks.
Protection status and accessibility:
The site is situated in the “Dolinki Krakowskie” Landscape Park and proposed to protection on the individual level. The Teaching Centre for students of geology is quite close to the quarry.
Character of site: Abandoned quarry
Area: 15 ha
Altitude: 420 m a.s.l.
Lithology: melaphyres, porphyries, conglomerates, breccias, dolostones, shales
Discipline: Petrography, Stratigraphy of Phanerozoic
Process Age: *all periods
Bedrock Age: Triassic, Permian, *all periods
Description of primary interest:
The volcanic rock of the Lover Permian age, forming a lava sheet up to 50 m thick, inclined gently eastward crop out in an old quarry, abandoned about 30 year ago. The quarry is large like a huge amphitheatre surrounded by walls up to 20 m high with a flat bottom and a small water body. The porphyry is massive, dark-red and brown-reddish, lighter after weathering. Small phenocrystals of feldspars, biotite and quartz reaching up to 6 mm occur within the rock matrix. The rock is intersected by joint forming columnar structures connected with the contraction during the cooling of lava. Big rocky columns generated by this process are visible on walls of the quarry, mainly in its northern part. The lava sheet is underlain with Upper Carboniferous shales and Lover Permian conglomerates. Transgressive deposits of the Lower Triassic (Röth) developed as sandy and marly dolomites containing thin lenses enriched in pebbles of porphyry. At the top they pass locally into cavernous limestones and dolomitic limestones. In the outcrop above the wall of the quarry few meters of these deposits are visible.
Literature:
ALEXANDROWICZ S. 1957–The Lower Buntsandstein in Czerna near Krzeszowice (Cracow Region). Instytut Geologiczny. Bul. 115. Mater. Geologii Obszaru Śląsko-Krakowskiego 4: 5-25. KOZŁOWSKI S. 1955–Porphyric intrusions in the Dębnik Ridge. Biuletyn Inst. Geol. 97. Mater. do geologii obszaru Śląsko-Krakowskiego 1: 39-102. SIEDLECKI S. 1948–Problems of stratigraphy of marine Triassic in the Cracow area (English sum.). Rocznik Pol. Tow. Geol. 18: 191-272. ZARĘCZNY S. 1894–Atlas geologiczny Galicji. Tekst do zeszytu trzeciego (Polish only). Wyd. Akademii Umiejętności. Kraków, 290 pp.