Late Quaternary insolation forcing on total organic carbon and C-37 alkenone variations in the Arabian Sea

We here present records of total organic carbon (TOC) and C-37 alkenones, u sed as indicators for past primary productivity, from the western (WAS) and eastern Arabian Sea (EAS). New data from an open ocean site of the WAS upw elling area are compared with similar records from Ocean Drilling Program ( ODP) Site 723 from the continental margin off Oman and MD 900963 from the E AS. These records together with other proxies used to reconstruct upwelling intensity, indicate periods of high productivity in tune with precessional forcing. On the basis of their phase relationship to boreal summer insolat ion they can be divided into three groups: in the WAS differences between m onsoonal proxies (1) and productivity (2) document a combined signal of mod erate SW monsoon winds and of strengthened and prolonged NE monsoon winds, whereas in the EAS phasing indicates maximum productivity (3) at times of s tronger NE monsoon winds associated with precession-related maxima in ice v olume.