New foraminiferal taxa and revised biostratigraphy of Jurassic marginal marine deposits on Anholt, Denmark

Abstract

On the north-eastern margin of the Danish Basin (part of the Mesozoic North Sea Basin) the Upper Pliensbachian to Toarcian succession represents the early phase of delta outbuilding, involving marine shelf, distal prodelta and proximal prodelta environments. The marine shelf conditions are characterized by calcareous foraminiferal assemblages dominated by the suborder Lagenina. The prodelta environments are typified by low-diversity agglutinated assemblages concentrated in discrete stratigraphical horizons. In total seventeen foraminiferal species were recognized, the following five of which are described here for the first time: Haplophragmoides propygmaeus, Ammobaculites bivarians, Ammobaculites nanogyrus, Kutsevella spilota, and Bulbobaculites vermiculus . The taxonomic treatment has also lead to a revised biostratigraphic scheme subdividing the foraminiferal succession into six assemblages confined to discrete stratigraphical intervals.