Foraminiferal and palynological biostratigraphy and biofacies from a Santonian–Campanian submarine fan system in the Vøring Basin (offshore Norway)

Abstract

Foraminiferal assemblages from a Santonian–Campanian submarine fan system in the northwestern Vøring Basin, offshore Norway were investigated with the primary objectives to document the stratigraphic ranges of foraminiferal taxa calibrated with dinoflagellate cysts, and to interpret foraminiferal biofacies of different fan sub-environments previously proposed based on the analysis of ichnofossils. The assemblages are composed of deep-water agglutinated foraminifera (DWAF) without carbonate-cemented taxa. DWAF taxa of high biostratigraphic value are absent, but the complete agglutinated nature of the assemblages and the presence of Gerochammina stanislawi and Rectogerochammina eugubina are similar to those of the lower Campanian Fenestrella bellii Zone of the Norwegian Sea. More reliable dating was provided by palynology, and the age of the interval is estimated to be Santonian to Campanian.The inner to middle fan assemblages contain small numbers of specimens, and consequently the species diversity and relative abundance of morphogroups are inconsistent. Deep infaunal forms may be more common in this sub-environment, but because the abundance is low, this observation should be treated carefully. In contrast, the abundance and diversity of the assemblages of the overbank, fringe and basin plain sub-environments are fairly high. Their morphogroup composition is also similar and comparable to each other when the assemblage size is large. The assemblage from the interval with suggested hydrothermal activity is similar to those from outside the channel sub-environment. The presence of bottom water currents, possibly in the form of a western boundary current, in the basin is suggested based on the abundant occurrence of tubular forms in the overbank, fringe, and basin plain sub-environments.