Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

Lithology and biostratigraphy of the Godula Formation within the Kněhyně Cave

 

Martin Kašing, Petr Skupien, Dalibor Matýsek

Geoscience Research Reports 53, 2020, pages 19–24

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Published online: 9 May, 2020

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Abstract

The research of pseudokarst caves in the Outer Western Carpathians is considered to be an important approach for recognition of various features of slope failures, e.g. its internal structure, depth, spatial extent, structural control, recent movement, age, etc. However, lithology and stratigraphy of rocks exposed inside the pseudokarst caves are still completely neglected. The results of petrographic, mineralogical and micropaleontological study of beds exposed in walls of the Kněhyně Cave are presented. Situated within southeastern slope of the Kněhyně Mt. in the Moravskoslezské Beskydy Mts., the Kněhyně Cave is a crevice-type cave developed within the middle member of the Godula Formation in the Silesian Unit. The investigation within the Kněhyně Cave enabled us to document the complete vertical profile of the cave. The lithological section of the cave represents a typical proximal flysch sequence characterized by alternation of the coarse-grained sandstones with thickness often reaching ˜ 3.5 m and up to ˜ 0.06 m thick aleuropelites. The mineralogical and paleontological analyses were carried out on 5 rock samples representing the finest members of turbidite cycle, corresponding to Td/Te interval of the Bouma sequence. High content of mica (50-70 vol. % of illite-muscovite; apparently 2M1 and 1M polytypes) and feldspar minerals (albitic plagioclase, potash feldspars) were proved by X-ray powder diffraction analysis. The amount of quartz is low (8 wt. %). The aleurites/pelites contain a large number of phytoclasts and deep-water dinoflagellates, indicating a material redeposition by turbidity currents. The identified dinoflagellate assemblages may be assigned to Lower/Upper Campanian transition.