Lithology and sedimentation of Upper Jurassic massive limestones near Bolechowice, Kraków-Wieluń Upland, south Poland

Jacek Matyszkiewicz, Marcin Krajewski


Litologia i sedymentacja górnojurajskich wapieni skalistych w rejonie Bramy Bolechowickiej na Wyżynie Krakowsko-Wieluńskiej

The major constituent of Upper Jurassic limestones which build Brama Bolechowicka (Bolechowice Gate, a group of valley-wall limestone rocks near Kraków) is massive limestone representing a complex of cyanobacterial-sponge carbonate buildups. Talus sediments of the buildup are present as clastic limestones exposed in isolated crags. Apparent bedding planes visible in the massive limestones are dissolution-widened fractures, fault joints and gently inclined shearing fractures in fault-related flexures. Limestones exposed ESE from Brama Bolechowicka represent interbiohermal facies and clastic sediments of variable age and origin. The Jurassic strata exposed ESE from Brama Bolechowicka lie within a wide fault zone which separates the Ojców Block from the Krzeszowice Graben. The variable dipping directions of these strata are caused mainly by the presence of hinge faults within this fault zone.

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