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Paleocene benthic and planktonic foraminifers occur throughout a long interval of the sedimentary succession cored at Site 605. A biostratigraphic zonation based on planktonic foraminifers is proposed for this Paleocene section. Zones identified are Subbotina pseudobulloides Zone, Morozovella trinidadensis Zone, M. uncinata Zone, M. pusilla pusilla Zone, Planorotalitespseudomenardii Zone, and M. velascoensis Zone. Fluctuations in the sedimentation rate occurred at Site 605. Rates of deposition were high during the M. pusilla pusilla and P. pseudomenardii zones, and a depositional hiatus may occur at the base of the M. velascoensis Zone. Qualitative and quantitative analysis of benthic foraminiferal assemblages suggests that the Paleocene sediments of Site 605 were deposited near the upper limit of Nuttallides truempyi, that is, approximately in the middle bathyal zone (600 m or more). INTRODUCTION Site 605 is located on the uppermost continental rise of the New Jersey Transect, in 2197 m of water, 100 miles southeast of Atlantic City, New Jersey (Fig. 1). Hole 605 was cored to 816.7 m and penetrated five lithologic units (Fig. 2). The oldest sediments drilled at this site (Subunit VB) are Maestrichtian in age. The Cretaceous/Tertiary boundary was reached at 760.2 m. The Paleocene section (Subunit VA and Unit IV) lies between 564 m (Paleocene/Eocene boundary) and 760.2 m. The lowermost Paleocene sediments (Subunit VA), 77 m thick, are composed of olive gray clayey limestones, rich in terrigenous silt (15-20%) and glauconite (2-4%). Unit IV, of middle and late Paleocene age, is made up of 176 m of dark greenish gray clayey nannofossil limestones. This unit is characterized by well-developed marl-limestone cycles and frequent bioturbation (Zoophycos burrows). This chapter discusses the planktonic and benthic foraminifers identified from the Paleocene sedimentary section recovered at Site 605. The primary objective of this study was to correlate Paleocene strata using standard planktonic foraminiferal zonations. A further objective was to investigate the benthic foraminiferal assemblages in the Paleocene sediments in order to interpret the environmental conditions of their deposition. PREPARATION OF SAMPLES Samples were prepared by standard methods. First, 10-cm samples were dried in a oven at 80-100°C for about 12 hr. for a dried sample weight of ~ 10-20 g. The weakly cemented sediment was disaggregated in water to which was added a spoonful of Calgon. This mixture was boiled for a few minutes to aid in disaggregation and partially clean the foraminifers. The treated samples were wet-sieved with a 0.160-mm mesh screen. The dried residue was examined for foraminifers. Some planktonic foraminifers were picked for taxonomic and biostratigraphic determination. All of the benthic foraminifers (> 0.160 van Hinte, J. E., Wise, S. W., Jr., Init. Repts. DSDP, 93: Washington (US. Govt. Printing Office). 2 Address: Laboratoire de Micropaléontologie et de Géologie Marines, Université de Nice , Pare Valrose, 06034 Nice Cedex, France. mm) were picked for a qualitative taxonomic determination and a subsequent quantitative study designed to provide tools for understanding paleoecologic and paleoceanographic conditions. Ratios calculated from the foraminiferal abundance data include (1) planktonic foraminifers/total microfauna, (2) agglutinated benthic foraminifers/all benthic foraminifers, and (3) abundance of benthic foraminifers expressed as specimens/g dry sediment. BIOSTRATIGRAPHY General agreement exists about the main Paleocene stratigraphic subdivisions based on the evolution of planktonic foraminifers. Among the numerous zonations proposed for the Paleocene interval, we have combined the zonations of Bolli (1966) and Hardenbol and Berggren (1978). Figure 3 gives ranges for common Paleocene planktonic foraminiferal species from Site 605. The planktonic foraminiferal species concepts used here are those of Stainforth et al. (1975). The generic concepts adopted are those of Boersma and Premoli Silva (1983). Above the Abathomphalus mayaroensis Zone, which is latest Maestrichtian in age, the following zones have been identified in the Paleocene section: 1. An undetermined zone at the top of Core 66 (60566-1, 0-120 cm; no sample available) (see Smit and Van Kempen, this volume). 2. The Subbotina pseudobulloides Zone (Plb) (Core 605-65) with its index species Globoconusa daubjergensis, S. triloculinoides, S. cf. fringa (in the lower part only), and Planorotalites cf. compressa (in the upper part). 3. The Morozovella trinidadensis Zone (Pic) (Sample 605-64,CC), with the index species, M. cf. inconstans, P. cf. compressa, S. pseudobulloides, and S. triloculinoides. Sample 605-64-4, 90-92 cm is entirely barren of planktonic foraminifers but contains some deep-sea benthic foraminifers (Nuttallides, Bulimina, Stilostomella), the tests of which are partly destroyed by dissolution. 4. The M. uncinata Zone (P2) was identified in the upper part of lithologic Subunit VA (Sample 605-64-2, 90-92 cm), based on the presence of M. uncinata, M. trinidadensis, M. cf. inconstans, Subbotina pseudobulloides, and S. triloculinoides.

Biostratigraphic and Paleoenvironmental Study of Paleocene Benthic and Planktonic Foraminifers, Site 605, Deep Sea Drilling Project Leg 93