Campanian to Maastrichtian palynofacies and dinoflagellate cysts of the Silesian Unit, Outer Western Carpathians, Czech Republic

Abstract

Dinoflagellate cysts are reported from 20 Upper Cretaceous claystone samples from the Godula and Istebna formations of the Silesian unit. Age-assessment of the sediments based on 150 species suggests a Late Campanian to probably earliest Maastrichtian age for the middle and upper part of the Godula Formation and a Early Maastrichtian age for the basal part of the Istebna Formation. Key biotic events are especially the first occurrence datums of Areoligera senonensis, Cerodinium diebelii, Palaeocystodinium golzowense and Trithyrodinium evittii, and the last occurrence datums of Odontochitina, Palaeohystrichophora infusorioides, Raeteiaedinium truncigerum, Trihyrodinium suspectum and Xenascus ceratioides. Palynofacies analysis shows deposition in an offshore marine environment subjected to influxes of terrestrial material. Organic matter is dominated by phytoclasts and contains very little amorphous organic material. The succession is also characterized by a low percentage of dinoflagellate cysts and a very low percentage of spores and pollen grains. The presence of thermophilitic dinoflagellate cysts points to a warm-temperate to subtropical climate during Late Campanian to Early Maastrichtian.