Biostratigraphy and Palaeoecology of Early Palaeogene Deep Water Foraminiferal Assemblages from the Subsilesian Unit in the Żywiec Tectonic Window (Polish Outer Carpathians)

Taxonomic composition, biostratigraphic significance and the morphogroup distribution of foraminifera have been analysed in the lower Palaeogene deposits of the Subsilesian Unit. The studied deposits consist mainly of hemipelagic/pelagic shales and marls and shaly turbidites deposited at considerable depths close to CCD. The foraminiferal assemblages dominated by deep-water agglutinated taxa represent four agglutinated foraminiferal zones: Rzehakina fissisto-mata, Spiroplectammina spectabilis (Paleocene), Glomospira div.sp. acme, and Saccamminoides carpathicus (Early Eocene). Palaeoecological conditions favoured the development of diversified microfauna occupying all ecological niches. The Paleocene/Eocene boundary crisis was pronounced by a decrease in taxonomic diversity and a mass occurrence of the genus Glomospira.