The Late Cretaceous–Early Paleocene palaeobathymetric trends in the southwestern Barents Sea — Palaeoenvironmental implications of benthic foraminiferal assemblage analysis

The Late Cretaceous foraminiferal assemblages from five wells drilled in the southwestern Barents Sea were analysed using morphogroup analysis in order to understand the palaeoenvironment and palaeobathymetry of the study area. Morphogroup analysis of assemblages in the Upper Cretaceous Kveite Formation suggests stable, possibly middle to lower bathyal, mesotrophic and relatively well-oxygenated environments in the Tromsø Basin during the Late Cretaceous. The depositional setting of Upper Cretaceous Kviting Formation in the tectonically more stable Hammerfest Basin was probably shallower, but still represents a deep-water environment similar to that of the Kveite Formation. A shallowing regional bathymetry in the southwestern Barents Sea is indicated by the general decreasing trend in the relative abundance of tubular forms and the species diversity of assemblages, which reflects the regional Late Cretaceous–Paleocene uplift prior to the break-up of the Greenland–Norwegian Sea. Changes in the relative abundance of morphogroups and in the main constituent in the cumulative length of tubular taxa from Rhizammina to Rhabdammina near the top of Kveite Formation agree with the possible existence of bottom water currents.

► Morphogroup analysis of Late Cretaceous foraminiferal assemblages.
► Bathyal, well-oxygenated and mesotrophic environments in basinal areas.
► Shallowing regional bathymetry towards the K/Pg hiatus.
► Possible existence of strong bottom currents around the K/Pg boundary.