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doi:10.2204/iodp.proc.329.202.2015

Introduction

Operations during Integrated Ocean Drilling Program (IODP) Expedition 329 (October–December 2010) drilled seven sites (U1365–U1371) spanning almost the entire width of the South Pacific Ocean (Fig. F1) and covering the full range of surface-ocean productivity conditions present in the South Pacific Gyre, ranging from extremely low productivity in the gyre center (Site U1368) to moderately high productivity at the southern edge of the gyre (Site U1371) (see the “Expedition 329 summary” chapter [Expedition 329 Scientists, 2011a]). This study reports on the semiquantitative radiolarian occurrences in 57 samples spanning the Neogene portion of the stratigraphic section recovered from Hole U1371D (Fig. F2; Plate P1) and provides a biostratigraphic record for Site U1371. This site was drilled southeast of Chatham Rise in the southwest Pacific at a water depth of 5301 m. It is the only Expedition 329 site located in the upwelling zone just south of the gyre at the northern edge of the Antarctic Convergence. The stratigraphic section recovered in Hole U1371D comprises ~108 m of clay-bearing diatom ooze overlying a ~21 m thick sequence of pelagic clay (Fig. F3). The hole was cored to basement (see the “Site U1371” chapter [Expedition 329 Scientists, 2011c]). Based on a tectonic reconstruction of the region by Larson et al. (2002), the site lies on ~73 Ma crust. The main aim of this study is to establish an age model for the sediment recovered at this site.

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