IMPROVING PAST SEA-SURFACE TEMPERATURE ESTIMATES BASED ON PLANKTONIC FOSSIL FAUNAS

A new method of past sea surface temperature (SST) reconstruction base d on the modem analog technique (Prell, 1985) and on the indirect appr oach (Bartlein et al., 1986) has been developed: the revised analog me thod (RAM). Applied to planktonic foraminifera, this technique leads t o significant improvements in modern SST reconstruction with respect t o former methods: our estimates are characterized by much lower residu als and a better coverage of the observed SST range. Moreover, the err or of RAM estimates of past SSTs is lower than that associated with fo rmer reconstructions, particularly at middle and high latitudes. In lo w latitudes, cold season SSTs reconstructed by RAM during glacials are 1 degrees-3 degrees C lower than previously estimated. Our results te nd thus to reconcile paleoestimates of glacial temperatures based on p lanktonic microfossils and on continental data in the tropics.