LATE PLEISTOCENE PALEOCLIMATOLOGY OF THE CENTRAL EQUATORIAL PACIFIC: FLUX PATTERNS OF BIOGENIC SEDIMENTS

High-resolution records of the concentration and mass accumulation rate (MAR, or flux) of biogenic sediments from core RC11-210 in the central equatorial Pacific are compared for the entire late Pleistocene. The fluxes of calcium carbonate and organic carbon correlate well. The opal flux pattern shows no direct correlation with the other two; rather, opal flux maxima correlate with slopes of (i.e. both precede and follow) the organic carbon and carbonate MAR peaks. Organic carbon and calcite therefore may both be better indicators of past productivity than opal, which is an indicator of transition at this location. We interpret the sequence low biogenic fluxes, high opal fluxes, high carbonate, carbon, and opal fluxes as representing the transition from low to high sea surface biological productivity. The phase relationships for eccentricity of the biogenic sedimentation records were compared to those of other climatic indications including the oxygen isotope record of ice volume, the ice core CO2 record, the Pacific Delta delta C-13 record, the deep nutrient (Cd/Ca) record, and the eolian grain-size record of wind intensity. We find that starting from maximum ice volume (phase angle of 0 degrees) the phase relationships of the 100,000-year periodicity show, in the first quadrant, maximum wind intensity (30 degrees) and maximum calcite and carbon flux (45 degrees) occurring first, followed by maximum opal flux (75 degrees) and then maximum deep nutrients (95 degrees). Minimum Pacific Delta delta C-13 occurs at a phase angle of 155 degrees, the maximum CO2 in the Vostok record and minimum ice volume is at 180 degrees. Thus, in the eccentricity climate cycle, glacial conditions lead to stronger wind-driven circulation which enhances productivity which in mm results in enhanced oceanic and atmospheric carbon dioxide and minimum ice volume.