Quaternary Ocean Paleochemistry

• Published in: Reviews of Geophysics
• Main Author: BOYLE, EDWARD A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1991
• Subjects: ice core
• Online Access: http://dx.doi.org/10.1002/rog.1991.29.s2.634; https://onlinelibrary.wiley.com/doi/pdf/10.1002/rog.1991.29.s2.634; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/rog.1991.29.s2.634; https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/rog.1991.29.s2.634

Data on Quaternary ocean paleochemistry has been expanded greatly during the past 4 years. Important new constraints on glacial deep ocean temperature and circulation patterns have been provided by the previously‐established paleochemical tracers δ 18 O, δ 13C , and Cd/Ca in benthic foraminifera. These have been complemented by information on ocean ventilation rates, and placed in an improved chronological reference frame, by AMS studies of 14 C in planktonic and benthic foraminifera. The 14 C time scale has been calibrated by mass spectrometric measurements of 230 Th in corals. The new radiometric techniques are also being used to re‐examine the accuracy of the late Quaternary time scale; the oceanic time scale may soon be linked to that of polar ice cores by AMS 14 C ice‐core dating and studies of the δ 18 O of atmospheric oxygen. A new interpretation of 230 Th in sediments offers the prospect of high resolution accumulation‐rate time series. Significant progress has been made in understanding oceanic factors that may cause reductions in atmospheric CO 2 during ice ages, although it is not yet clear which if any of these factors dominates CO 2 variability. A number of new geochemical paleoceanographic tracers have been developed and refined during the past 4 years, and high‐resolution study of oceanic paleochemical changes has been extended to the entire Pleistocene period for the first time.