In order to analyze the surface water dynamics in the Peru upwelling system zone during the last 800 Ka,
we studied the calcareous nannofossil content. The ODP site 1237 coccolith assemblage revealed two
dominant taxa: «small» Gephyrocapsa and Florisphaera profunda. The «small» Gephyrocapsa abundance
increased between 0,2 and 0,45 Ma allowing us to interpret a shallow nutricline consequent with a Trade
wind intensification. Relative increases in the Florisphaera profunda abundance occurred between 0,86-
0,45 Ma and 0,20-0 Ma consistent with a deeper nutricline and weaker Trade winds. Spectral analyses in
the Florisphaera profunda percentages show orbital frequences with peaks at 100, 41 and 23 Ky
