(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.

在DSDP第93航次期间，于美国东海岸大陆坡的603号地点钻探了三个孔。603C孔中回收了厚层的上新世地层以及最下部数米的第四纪沉积物。基于浮游有孔虫分布的详细生物地层学研究，我们精确地划定了所有上新世地层（参照Berggren，1977年的分类）。第四纪地层已侵蚀至Ericson的P区之外。计算得到的沉积物累积速率在大部分上新世时期保持相对较高，在PL4区达到最大值150米/百万年。定量微体古生物学方法使我们能够划定了数个古气候和古海洋学事件，包括4.3百万年和3.4百万年时期的事件。