Late Quaternary changes of warm current system in the northwestern Pacific Ocean from the equator to the Ryukyu Island Arc region.

1)对琉球海沟斜坡区3个柱状岩心的变量分析表明，钙质纳米浮游生物Florisphaera profunda的下核变化反映了晚第四纪海水浊度（=初级产物）的变化。2)冲绳海槽和琉球岛弧的原型出现在中更新世。③石垣岛南部两个岩心底栖有孔虫的变化反映了近210 ka来海底水的变化。4)为了通过沉积序列更准确地了解动物区系变化，对一个珊瑚礁区（使用62个沉积物样本）和一个电池环境（使用56个真实表面样本）进行了近期底栖有孔虫组合的详细和多元分析。5)为了解后冰期黑潮与亚洲大陆河流携带的沉积物质之间的关系，在冲绳海槽采集了9个岩心，并采用多种方法进行了研究。根据有机碳氮比和木质素酚含量的下核变化，只有陆源植物碎片供应呈稳定下降趋势。这意味着在最后一次冰期期间，连接台湾、冲绳和奄美大岛的陆桥逐渐消失。这种消失模式得到了黑潮浮游有孔虫群（pulleniatina group）上升的支持。这个群体在距今3800年前的几百年间突然消失了。表明上述陆桥或类似情况的临时形成。

1) Variable analyzes of three piston cores taken from the Ryukyu Trench slope area revealed that down-core change of Florisphaera profunda, a calcareous nannoplankton, indicate sea-water turbidity (=primary production) change during the late Quaternary. 2) Prototypes of the Okinawa Trough and the Ryukyu Island Arc appeared during the Middle Pleistocene. Afterward, the Kuroshio Current has entered into the Trough. 3)Benthic foraminiferal changes in two cores taken from the south of Ishigaki Island reflected bottom water changes during the past 210 ka. 4) To more precisely understand the faunal change through sedimentary sequences, the detailed and multivariate analyzes of Recent benthic foraminiferal assemblages were completed for a coral reef area (62 sediment samples used) and for the batyal environment (56 real surface samples used). 5) To know the relationship between sedimentary materials carried by the Kuroshio Current and by Asiatic continental rivers during the post-glacial period, nine cores were collected from the Okinawa Trough and investigated by variable methods.Only a terrigenous plant fragment supply indicate steady decrease toward Recent according to the down-core changes of organic carbon/nitrogen ratio and lignin-phenol content. This means the gradual disappearance of a land-bridge connected Taiwan through Okinawa to Amami-ohshima during the last glacial episode. This disappearance mode was supported by a upward increase of pulleniatina group, planktonic foraminifera characteristic of the Kuroshio Current. This group suddenly disappeared during a few hundred years at - 3,800 yr.BP., suggesting a temporary formation of the above land-bridge or of similar situation.