CHARACTERISTICS OF THE DEEP-OCEAN CARBON SYSTEM DURING THE PAST 150,000 YEARS - SIGMA-CO2 DISTRIBUTIONS, DEEP-WATER FLOW PATTERNS, AND ABRUPT CLIMATE-CHANGE

Studies of carbon isotopes and cadmium in bottom-dwelling foraminifera from ocean sediment cores have advanced our knowledge of ocean chemic al distributions during the late Pleistocene. Last Glacial Maximum dat a are consistent with a persistent high-Sigma CO2 state for eastern Pa cific deep water, Both tracers indicate that the mid-depth North and t ropical Atlantic Ocean almost always has lower Sigma CO2 levels than t hose in the Pacific, Upper waters of the Last Glacial Maximum Atlantic are mure Sigma CO2-depleted and deep waters are Sigma CO2-enriched co mpared with the waters of the present, In the northern Indian Ocean, d elta(13)C and Cd data are consistent with upper water Sigma CO2 deplet ion relative to the present, There is no evident proximate source of t his Sigma CO2-depleted water, so I suggest that Sigma CO2-depleted Nor th Atlantic intermediate/deep water turns northward around the souther n tip of Africa and moves toward the equator as a western boundary cur rent, At long periods (>15,000 years), Milankovitch cycle variability is evident in paleochemical time series, But rapid millennial-scale va riability can be seen in cores from high accumulation. rate series, At lantic deep water chemical properties are seen to change in as little as a few hundred gears or less, An extraordinary new 52.7-m-long core from the Bermuda Rise contains a faithful record of climate variabilit y with century-scale resolution, Sediment composition can be linked in detail with the isotope stage 3 interstadials recorded in Greenland i ce cores, This new record shows at least 12 major climate fluctuations within marine isotope stage 5 (about 70,000-130,000 gears before the present).