Glacial intermediate water ventilation in the northwestern Pacific based on AMS radiocarbon dating

C-14 ages of benthic foraminifera and planktonic foraminifera in sediment core PC4 (41degrees07.10'N, 142degrees24.17'E) collected from the northwestern Pacific were measured by accelerator mass spectrometry. The purpose of this study was to investigate the changes in intermediate water ventilation in the northwestern Pacific during the last glacial period. We used age differences between benthic foraminifera and planktonic foraminifera from the same sediment horizons to estimate the ventilation time of intermediate water. Planktonic C-14 ages show that the core recorded paleoenvironmental changes during the last 35 kyr. Glacial benthic-planktonic age differences were smaller in the early deglacial period (15000-17000 cal yr BP) than in the period (19000-30000 cal yr BP) before and during the last glacial maximum. The results at intermediate depths are consistent with those from a Pacific deep-water site. (C) 2004 Elsevier B.V. All rights reserved.