GLACIAL TO INTERGLACIAL FLUCTUATIONS IN PRODUCTIVITY IN THE EQUATORIAL PACIFIC AS INDICATED BY MARINE BARITE

An empirical correlation between marine barite (BaSO4) accumulation ra te in core-top sediment samples from two equatorial Pacific transects (at 140 degrees W and 110 degrees W) and the estimated primary product ivity of the overlying water column were used to evaluate glacial to i nterglacial changes in productivity. Fluctuations in barite-accumulati on rates down-core indicate that during glacial periods of the past 45 0,000 years, the productivity in the central and eastern equatorial Pa cific was about two times that during intervening interglacial periods . This result is consistent with other evidence that productivity was high in the eastern and central equatorial Pacific during the last gla cial.