Cretaceous sandstones, Matějovická cave, Pseudokarst, Speleogenesis

Článek popisuje genezi a vývoj Matějovické jeskyně na Osoblažsku. Jeskyně představuje pseudokrasový systém, vyvinutý v cenomanských pískovcích. Článek hodnotí předchozí teorie vzniku a vývoje a diskutuje je ve světle nově zjištěných faktů a výsledků současného výzkumu.

The Matějovická Cave is a small underground cavity in the north-eastern portion o f Czechia. The cavity is formed in the western steep slope above the bottom o fthe Hrozová valley. It is formed in the Cenomanian sandstones with subhorizontal layering stratification and transversal subvertical ruptures (NNE-SSW, NW-SE). The system of several short corridors and two bigger chambers is 25 m long. The corridors are terminated by phreatic channels. The ceiling is formed by lower bedding planes, the bottom is filled by debris and sand. Two main chambers are disrupted by several transversal ruptures. The entrance chamber is disrupted by a distinct weak tectonic zone with petrographical attributes different from the surrounding rock. We identified the Liesegang rings within this structure. The differences in composition are detectable between the samples from the cavity and from the superficial environment. The investigated cavity should be considered a pseudokarst cave, which was discovered during historical mining works. The cave was formed by the erosion of incoherent sandstones by groundwater permeating into the massi falong ruptures and bedding planes after the onset of the incision of the Hrozová River during the Alpine orogeny. The cave is a combination o f fissure and bedding cave types or fluvial channel erosion cave combined with exfoliation cave.