MICROFAUNAL, TEMPERATURE, PRODUCTIVITY, AND VENTILATION CHANGES ON THE FARALLON ESCARPMENT OFF CENTRAL CALIFORNIA DURING THE LAST 16,000 YEARS

New benthic and planktic foraminiferal assemblage census data and Benthic Foraminiferal Oxygen Index (BFOI) values, previously published marine climate proxy data (stable isotopes and Ca/Cd), and unpublished results of total carbon, organic carbon, and calcium carbonate analyses of sediments recovered off central California on the Farallon Escarpment (1605 m; 37°13.4'N, 123°14.6'W; core F-8-90-G21) are used to investigate paleoceanographic changes during the latest Quaternary. Radiocarbon dates provide an excellent age-depth model covering the latest glacial, BØlling-AllerØd, Younger Dryas, and early, middle, and late Holocene intervals. A Q-mode cluster analysis separated the benthic fauna into three clusters, one Pleistocene and two Holocene, whereas the planktic fauna was divided only into Pleistocene and Holocene clusters. Stable oxygen isotope values show an increase in water temperature of ~1°C from the late glacial to late Holocene and a change in faunal composition of the planktic assemblage suggests surface waters warmed as well. A general trend of decreasing dissolved oxygen concentration from the Pleistocene (high oxic; 3.0-6.0+ ml/L O₂) to the Holocene (low oxic; 1.5-3.0 ml/L O₂), reflecting decreased ventilation, is evident in the BFOI data and agrees with the Cd/Ca data except between ~13,000-11,000 cal yr BP. The middle Holocene cooling suggested in other central and northern California margin studies is not evident in F-8-90-G21, which compares more favorably with studies from southern California and British Columbia. Total carbon and organic carbon values are highest in the BØlling-AllerØd, early Holocene, and late Holocene. Similarly, calcium carbonate values are high in the BØlling-AllerØd and peak in the early Holocene, but decrease significantly in the latest middle and late Holocene which coincides with a depauparate planktic fauna in the upper 60 cm (~0-7,000 cal yr BP) of the core and poor preservation of the benthic fauna at 40 cm (~0-3,000 cal yr BP). Decoupling is evident between the planktic and benthic faunal response to changing climatic conditions, with the surface-dwelling assemblage often leading the bottom-dwelling assemblage by several millenia.