1. Biostratigrafie, litologie a mineralogie hlubokovodních sedimentù barnasiówského souvrství na bøehu Krnalovického potoka u Rychaltic.
- Author
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STELMACH, PETR, SKUPIEN, PETR, and MATÝSEK, DALIBOR
- Subjects
TONSTEINS ,INCRUSTATIONS ,DINOFLAGELLATE cysts ,CHERT ,MINERALS - Abstract
The studied section belongs to the Barnasiówka Formation of the Baška Development in Silesian Unit of the Outer Western Carpathians. Similar sections and their sediments are observed in the Silesian Unit in the Czech Republic (Skupien et al. 2016; Stelmach et al. 2018) and in the Silesian and Skole units in Poland (Bąk et al. 2001 and 2007). The Barnasiówka Formation is typical of the occurrence of fine-grained deep-see sediments, mainly non-calcareous or partly calcareous claystones (shales) and cherts with manganese crusts and incrustations (Bąk et al. 2001). Outcrops of the Barnasiówka Formation can be found on the NW slope of the Palkovické hůrky hills, 600 m northwards of the Přední Babí hora mountain at the southern edge of a small village of Krnalovice, on the left bank of the Krnalovický potok brook. The section in its lower part consists of dark-grey to black laminated claystones (samples KRN 1 and KRN 2) and light-green to greygreen laminated claystones alternating with cherts disintegrating into small fragments of brown-grey to dark-grey color shades confined to the remnants of major part of the section (samples KRN 3 - KRN 9) - see Fig. 3. Total thickness of the section is 5.4 m. Stratigraphically important representatives of Lower Turonian noncalcareous dinoflagellates were identified in samples of dark pelitic sediments. These include first occurrences of Heterosphaeridium difficile, Chatangiella granulifera, Senoniasphaera rotundata, and Senoniasphaera turonica (Costa and Davey 1992; Stover et al. 1996; Williams et al. 2004). However, the Lower Turonian age of the samples studied was also confirmed based on the last occurrence of Litosphaeridium siphoniphorum (Costa and Davey 1992; Stover et al. 1996). The local rocks are rich in Mn oxides and hydroxides, to lesser extent occur Fe oxides and hydroxides in the form of coatings and incrustations, dendrites or filling fissures and fractures. Abundant Mn minerals (todorokite, pyrolusite and rancieite) were found close to KRN 4 and KRN 5 samples which were taken from the base of Turonian. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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