Nannofossil range charts are presented in Tables T1, T2, T3, and T4, and nannofossil age-depth control points are summarized in Table T5. Age control for the lower part of Hole 1171D is very poor because Cores 189-1171D-58R through 75R are largely barren of nannofossils (Table T3). However, rare occurrences of the genera Toweius and Prinsius in a number of samples, with the lowermost occurrence in Sample 189-1171D-74R-CC, suggest that the interval is of Paleocene-earliest Eocene age. Similarly, Cores 189-1172D-10R through 24R are virtually barren of nannofossils, but the occurrences of Coccolithus pelagicus and Reticulofenestra sp. in Core 189-1172D-24R suggest that this core is of Paleocene-Eocene age. Samples from the next core (189-1172D-25R) and downhole are clearly of late Maastrichtian age, as they contain typical late Maastrichtian nannofossils, including Arkhangelskiella cymbiformis, Cribosphaerella daniae, Eiffelithus turriseiffelii, and Nephrolithus frequens (see Exon, Kennett, Malone, et al., 2001).
The nannofossil biostratigraphic results presented here appear to be significantly different from those of the shipboard results and the preliminary shore-based studies of other fossil groups for the critical Eocene-Oligocene transition, and the paleoceanographic implications appear to be quite significant. Thus, we prefer to defer detailed discussion of the nannofossil biostratigraphy and its implications until more thorough evaluation of the data together with those of other stratigraphic data sets.