Early Cretaceous ammonites and dinoflagellates from the Western Tatra Mountains, Poland

Abstract

The first Early Cretaceous (Valanginian–Hauterivian) ammonite fauna from the lower part of the Kościeliska Marl Formation (Wściekły Żleb Member) of the Lower Sub-Tatric (Krížna) Nappe, in the Lejowa Valley of the Tatra Mountains are described. The fauna is precisely placed in the succession and consists of five species: Olcostephanus densicostatus, Spitidiscus cf. cankovi, Criosarasinella cf. subheterocostata, Crioceratites primitivus, and Crioceratites coniferus and additionally an aptychus Didayilamellaptychus seranonis. Remarkable are the valves of anomiid bivalves attached to body chamber of large size heteromorph ammonite C. primitivus. Moreover, a variety of stratigraphically important organic-walled dinoflagellate cysts are recovered from this locality. Dinoflagellates: Cymososphaeridium validum, Circulodinium vermiculatum, and representatives of Bourkidinium define the Upper Valanginian–Lower Hauterivian Sentusidinium sp. A Dinocyst Subzone of the Cymososphaeridium validum Zone. The character of deposits, the palynofacies, and associations of dinoflagellate cysts indicate a calm marine outer neritic environment.

Keywords

• ammonoidea
• anomiidae
• dinoflagellata
• valanginian
• hauterivian
• western carpathians