Miocene calcareous nannofossil biostratigraphy of Deep Sea Drilling Project Hole 521A (southeast Atlantic).

Abstract

The middle/lower upper Miocene coccolith biostratigraphy of Cores 12 and 13 in Hole 521A is given, and the reasons for the absence of Helicosphaera and Sphenolithus in most of the interval studied are speculated upon. The lowest occurrence of Catinaster coalitus, which defines the base of NN8 in Magnetostratigraphic Chron C-5, confirms the observations made at Site 519 and at Hole 521 and suggests that the numerical age of NN8 is younger than previously supposed.- Author