Site 1017 was one of a suite of late Neogene cores drilled along the California margin during Ocean Drilling Program (ODP) Leg 167 to further understand the geologic history of the California Current system since the late Miocene (Lyle, Koizumi, Richter, et al., 1997). The California Current is known to have undergone a dynamic evolution during the Neogene (Ingle, 1977), but little detail is known. Site 1017 is located in the coastal upwelling zone of the current 55 km west of Point Arguella on the upper part of the continental slope (Santa Lucia Slope; 34°32´N; 121°6´W) at a water depth of 956 m (Fig. 1). Strong coastal upwelling at this location enhances biological productivity, and Site 1017 is located in the lower part of the oxygen minimum zone (Gardner et al., 1997). High sedimentation rates (average = ~18 cm/k.y.) during the late Neogene at Site 1017 result from considerable terrigenous sediment supply from nearby continental sources to the east. The sequence contains a continuous record of abundant planktonic and benthic foraminifers, diatoms, and radiolaria necessary for high-resolution, late Neogene paleoclimatic/paleoceanographic investigations. The high sedimentation rate at this location provides an important opportunity to resolve millennial-scale climatic cycles during the latest Quaternary (Dansgaard et al., 1993) now well resolved in the nearby Santa Barbara Basin Site 893 (Kennett and Ingram, 1995; Behl and Kennett, 1996; Hendy and Kennett, 1999; Cannariato et al., 1999). However, the sediments are bioturbated throughout Hole 1017E, unlike the Santa Barbara Basin (Kennett, Baldauf, et al., 1994), which reduces stratigraphic resolution.
Hole 1017E was dedicated to examine, at very high resolution, paleoclimatic and paleoceanographic changes during the latest Quaternary. Objectives include examination of changes in (1) the California Current immediately north of the California Borderland and its interaction with the northward-flowing California Countercurrent and Undercurrent, (2) the oxygen minimum zone, (3) coastal paleoproductivity in the open-ocean California Current, and (4) intermediate waters along the California margin. Significant progress has been made toward understanding the late Quaternary evolution of these California Current system components (e.g., Keigwin and Jones, 1990; Mortyn et al., 1996; van Geen et al., 1996; Gardner et al., 1997, and references therein). Hole 1017E offers much potential to build upon these investigations.
These investigations require an age model of sufficiently high chronological resolution to resolve millennial-scale climatic events. This contribution presents an age model for Hole 1017E based upon radiocarbon chronology and oxygen isotopic stratigraphic correlations. Both benthic and planktonic foraminifers are abundant enough throughout the sequence to provide the necessary materials for our high-resolution stable isotopic investigations.