(Table 2) Relative abundance of planktonic foraminifera species in Pliocene - Early Quaternary sediments from ODP Hole 111-677A

Planktonic foraminifera from Pliocene - Early Quaternary sediments of ODP Hole 111-677A were studied in detail. It was shown that the majority of detected zonal taxa are reliable biostratigraphic reference points. Between 30 and 210 m in the core zones of planktonic foraminifera from PL1b to Pt1 (according to the W.A. Berggren scale) were distinguished. Changes of planktonic foraminifera complexes from sediments of Hole 111-677A are closely associated with climate-controlled development of surface water masses of the Eastern Equatorial Pacific during 4.6-0.65 million years ago. Sharp decrease in equatorial-tropical species about 3.4 million years ago correlated with cessation of surface water exchange between tropical regions of the Pacific and Atlantic oceans due to formation of the Central American isthmus. The paleotemperature method of M.S Barash was used for reconstructing surface temperatures. Maximum temperatures were reconstructed in late Early Pliocene (26.4°C) and in Late Pliocene (26.6°C) and minimum ones - in the beginning of Early Pliocene (18.4°C), in the middle of Late Pliocene (19.6°C). Cold events occurred: 4.6-4.3, 2.8-2.5, and 1.7-1.2 million years ago, and warm: 4.3, 4.18-3.4, 2.5-2.3, and 1 million years ago. In general, the middle of Early Pliocene, the middle of late Pliocene and early Pleistocene are characterized by cold-water conditions, and the end of Early and the end of Late Pliocene - by warm-water conditions.

对大洋钻探计划（Ocean Drilling Program，ODP）111-677A钻孔上新世-早第四纪沉积物中的浮游有孔虫（planktonic foraminifera）开展了详细研究。研究表明，绝大多数检出的分带类群均为可靠的生物地层学参考标志。在岩芯30~210米层位中，依据W.A.伯格伦（W.A. Berggren）的划分方案，可识别出从PL1b至Pt1的浮游有孔虫带。111-677A钻孔沉积物中浮游有孔虫组合的演替，与4.6~0.65百万年前东赤道太平洋表层水团受气候调控的演化过程密切相关。约3.4百万年前赤道热带属种出现丰度骤减，这一现象与中美洲地峡形成导致太平洋与大西洋热带区域表层水交换中断存在显著关联。采用M.S.巴拉什（M.S. Barash）的古温度重建方法，获取了表层海水温度序列：早上新世晚期（26.4℃）与上新世晚期（26.6℃）为温度峰值阶段，早上新世初期（18.4℃）与上新世晚期中期（19.6℃）为温度谷值阶段。研究识别出多期冷、暖气候事件：冷事件发生于4.6~4.3、2.8~2.5及1.7~1.2百万年前；暖事件发生于4.3、4.18~3.4、2.5~2.3及1百万年前。总体而言，早上新世中期、上新世晚期中期及早更新世时期以冷水环境为特征，而早上新世末期与上新世晚期末期则发育暖水环境。