Calcareous nannofossils from the North Atlantic Ocean, Leg 49, Deep Sea Drilling Project.

Abstract

The oldest sedimentts encountered are lower M Oligocene (Helicopontosphaera reticulata Zone), at Site 407. Sediments generally contain abundant, well-preserved nannofossils. In those samples containing few nannofossils, large amounts of volcanic sediments and siliceous microfossils account for the dilution. There is little evidence of dissolution. Species are relatively diverse, although many of the indicator species commonly used for zonation in lower latitudes (ceratoliths, discoasters, and sphenoliths) are missing. -Author