(Figure 2) Planktonic foraminifera abundance in DSDP Hole 93-603C

Three holes were drilled at Site 603 on the continental rise off the U.S. east coast during DSDP Leg 93. A thick Pliocene section and a few meters of lowermost Quaternary sediments were recovered in Hole 603C. A detailed biostratigraphic analysis, based on planktonic foraminiferal distribution, allowed us to delineate precisely all the Pliocene zones (sensu Berggren, 1977). The Quaternary sequence was eroded beyond Ericson's Zone P. The calculated sediment accumulation rate remained relatively high during most of the Pliocene, reaching a maximum of 150 m/Ma in Zone PL4. Quantitative micropaleontological methods enabled us to delineate several paleoclimatic and paleoceanographic events, including those at 4.3 and 3.4 Ma.