Skluzova telesa a biostratigrafie basskeho souvrstvi na lokalite Vlcovice (slezska jednotka)

This study focuses on the geological and paleoecological evaluation of the Baška Formation (Silesian Unit, Outer Western Carpathians) at the Vlčovice locality. Research was based on field documentation along three lithological profiles (P1, P2 and P3) parallel and transverse to the Lubina River with a total length of approximately 150 m. The studied section represents a typical flysch sequence composed mainly of fine-grained calcareous laminated marlstone and organogenic limestone alternating with claystone, which pass upwards into sequences with frequent sandstone layers. The strata are tectonically overturned, with dips varying significantly from 20° to 75° to the east-northeast.

A key feature of the locality, particularly along the P3 profile, is the presence of slump bodies and olistostromes. These chaotic intervals contain large limestone blocks (olistoliths), the largest reachingof 6.5 × 4.4 × 1.5 m in size, along with exotic clasts of coal. These features indicate gravitational transport in the tectonically active basin slope environment.

Samples of the claystones and marlstones yielded rich dinoflagellate cyst assemblages (64 species). Biostratigraphic evaluation places the sediments in the Upper Albian to Lower Cenomanian interval. This age determination is supported by Upper Albian markers such as Palaeohystrichophora infusorioides and Pervosphaeridium pseudhystrichodinium . The upper stratigraphical limit is constrained by the occurrence of Cribroperidinium edwardsii, a species that disappears in the Lower Cenomanian. No species characteristic of the Middle Cenomanian were recorded. Additionally, deformed bivalves of the genus Inoceramus sp. were found along the P1 profile.

Palynofacies analysis reveals high heterogeneity in the organic matter composition. Samples are often dominated by black rounded phytoclasts (up to 38 %), suggesting a proximal oxic shelf environment with terrestrial input (based on the Tyson diagram). However, the degree of preservation of amorphous organic matter (AOM) varies significantly between adjacent layers, ranging from anoxic signatures to oxic conditions. This sharp contrast supports the sedimentological interpretation that the material was redeposited within slump bodies, resulting in the mixing of sediments from different original depositional settings.

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