INTRODUCTION

Ocean Drilling Program (ODP) Leg 174A drilled a transect of three sites on the continental margin off New Jersey to study sea-level history. The primary goals of Leg 174A "are to (1) date unconformities (sequence boundaries) of Oligocene to Holocene age and to compare this stratigraphic record with the timing of glacial eustatic changes inferred from deep-sea ¹⁸O variations ...." (Leg 174A Scientific Prospectus [http://www-odp.tamu.edu/publications/prosp/174a_prs/174aabstr.html]). Shipboard studies showed that the primary means of dating the sedimentary sequences recovered during Leg 174A was nannofossil biostratigaphy. However, shipboard nannofossil biostratigraphy was generally based on data from core catcher samples. The purpose of this shore-based study is to examine these core catcher samples in more detail and to examine samples within core sections. These analyses will improve the reliability and stratigraphic resolution beyond those of the shipboard biostratigraphy by identifying additional age-diagnostic species (particularly within the cores) and by locating the zonal/subzonal boundaries more precisely. With improved biostratigraphy, we should be able to date the unconformities (sequence boundaries) with better precision and to better correlate the geologic events identified in Leg 174A cores with those recorded in other parts of the world. An improved biostratigaphy is important, as much of the cored intervals do not yield useful magnetostratigraphy due to generally low core recovery and disturbed cores.

Previous studies of Eocene-Pleistocene nannofossils in the vicinity of Leg 174A sites include those of Mountain, Miller, Blum, et al. (1994), Gartner and Shyu (1996), and Aubry (1996).