Late Pleistocene upwelling and productivity variations in the northwest Indian Ocean deduced from spectral analysis of geochemical data from Sites 722 and 724

Abstract

Productivity records are coherent with carbonate, but not ice volumes at the 23 k.y. period. Additionally, productivity and %CaCO3 are in phase at the 100 and 41 k.y.periods. We suggest that at these frequencies, productivity is related to the supply of nutrients from continental runoff and hence aridity. At the 23 k.y. period, productivity variations lagged %CaCO3 by about 40° suggesting that as well as runoff there was another, delayed source of nutrients, possibly intermediate water upwelled by the effect of the Southwest Monsoon. -from Authors