Palaeoecology and biostratigraphy of the fine-grained deposits from the Radčice section (Cantabrian, Plzeň Basin)

 

Jana Drábková, Richard Lojka, Zbyněk Šimůnek

Geoscience Research Reports 38, 2005 (GRR for 2004), pages 30–33

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Abstract

Fine-grained deposits of the Radcice section occur as a relatively thick laterally stable horizon at basal part of the section and as laterally confined thin lenses at mid parts. The first one interpreted as floodplain deposits with tuffaceous layers yielded relatively rich palynological assemblages and some floral remains. On the contrary, the second ones interpreted as abandoned channel-fills yielded only impoverished palynological assemblage. Floral remains are represented by the species Calamites cistii, Sphenophyllum oblongifolium and Praecallipteridium rubescens from the basal part of the horizon; Psaronius sp. And lAsterophyllites sp. or Annularia sp. come from the tuffaceous layer and many Cordaites remains from the overlaying siltstone layer. Palynological assemblages obtained from floodplain deposits indicate the equivalency with the Nevren Coal Seams of Cantabrian age. Sphenophyllum oblongifolium indicates the beginning of the Cantabrian biozone 3 (Cleal et al. 2003). Megaspores obtained from floodplain deposits are represented by species Calamospora laevigata, Laevigatosporites glabratus, Tuberculatisporites sp., Triangulatisporites triangulates, T. tertius, Bentzisporites sp. and Schopfipollenites ellipsoides that indicate occurrence of Calamites, Sigillaria, Selaginella, and pteridosperms. Monolete microspores of some pecopterids (Punctatosporites spp., Speciososporites spp., Laevigatosporites spp.) are common, spores of Calamites (Calamospora spp.) and Cordaites (Florinites spp.) are abundant in some samples. Species characteristic for Westphalian D of the Bohemian Massif Vestispora fenestrata, Cirratriradites saturni are present. Stratigraphically younger species of Stephanian character e.g. Punctatosporites speciosus, Speciososporites spp. Gillespieisporites spp. Guthorlisporites magnificus, Candidispora candida, Wilsonites delicatus, Wilsonites vesicatus, Limitisporites sp. and Potonieisporites novicus also occur. Palynological assemblages obtained from floodplain deposits could be assigned to the LG-PS (Lagenoisporites glabratus - Punctatosporites speciosus) zone (Kalibova 1983) and indicate the equivalency with Nevren Coal Seams of Cantabrian age. Palynological assemblages with Florinites spp. Wilsonites spp. Potoniesporites spp. Kosankeisporites elegans, Angulisporites sp., Protohaploxipinus sp. isolated from the above abandoned channel-fills seem to be of younger character and could indicate Barruelian age.