Dinoflagellate cyst biostratigraphy of Upper Cretaceous strata from two wells in the Norwegian Sea

•One new and seven previously established palynostratigraphic zones are described from the Norwegian Sea.•Late Albian to late Maastrichtian age is estimated for the studied composite section.•Late Maastrichtian dinoflagellate cyst assemblages are recorded from both wells.•They are compared to assemblages from ammonite and belemnite zones in the adjacent areas.

Rich assemblages of dinoflagellate cysts from two sections in the Norwegian Sea provide a solid basis for a palynostratigraphic framework for the upper Albian to upper Maastrichtian succession in this area. The framework is based on a unique composite section combining samples from the shallow stratigraphic core 6711/4-U-1 and core-samples from well 6707/10-1, the latter filling in data from the intervals represented by hiatuses in core 6711/4-U-1. Seven previously described, and one new palynostratigraphic zone, are recognised. These are based on the relative abundances of prominent taxa together with top and base occurrences of selected age-diagnostic dinoflagellate cyst taxa. The zones and their ages in ascending order from the oldest to youngest comprise: the intra late Albian to intra early Cenomanian Subtilisphaera kalaalliti Interval Zone sensu Nøhr-Hansen (1993a); the intra early Cenomanian to intra late Cenomanian Palaeohystrichophora infusorioides–Palaeohystrichophora palaeoinfusa Interval Zone sensu Radmacher et al. (2014b); the Turonian to ?intra early Coniacian Heterosphaeridium difficile Interval Zone sensu Nøhr-Hansen (2012); the ?intra early Coniacian to late Santonian Dinopterygium alatum Interval Zone sensu Radmacher et al. (2014b); the early Campanian Palaeoglenodinium cretaceum Interval Zone sensu Radmacher et al. (2014b); the new intra Campanian Hystrichosphaeridium dowlingii–Heterosphaeridium spp. Interval Zone; the intra late Campanian Chatangiella bondarenkoi Interval Zone sensu Radmacher et al. (2014b) and the intra late Maastrichtian Wodehouseia spinata Range Zone sensu Nøhr-Hansen (1996). Comparison of the palynological events with records in adjacent regions enables correlation across similar paleolatitudes in the Northern Hemisphere.