| 摘要: |
| 格陵兰冰芯的δ18O记录表明，末次冰期的气候发生了一系列快速的冷暖交替过程，即所谓的Dansgaard-Oeschgerk旋回(Dansgaard et al.,1995；Stuiver et al.,1995；Grootes et al.,1997)。在北大西洋区域，海洋的沉积记录也清楚地再现了在总的冰期背景下代表强烈冰川漂移事件的6次变冷事件,即所谓的Heinrich事件(Bond et al.,1992，1993；Rasmussen et al.,1997；Andrews,1998)。通过对比发现Dansgaand-Oeschger旋回和Heinrich事件并非两个孤立的气候演变过程,Heinrich事件(H)发生在Dansgaard Oeshger旋回的最冷期，几次大的Heinrich事件使格陵兰的大气温度在冰期的气候条件下又降低3-6℃(Mayewski et al.，1997)。随后，越来越多的研究成果表明，这些气候事件的发生，尤其冷事件并不仅限于格陵兰和北大西洋等北半球的高纬度地区，几乎在全球各大区域均找到了它们的印记。
冲绳海槽作为西太平洋的一个弧后盆地，其较高的沉积速率和对全球气候变化的“放大效应”，为我们识别过去地质历史时期气候演化事件并进行全球对比提供了可靠的保证。本文作者对取自冲绳海槽北部的CSH1孔的孢粉组合和中部DGKS9603孔的浮游有孔虫动物群进行了分析，以期获得有关北半球高纬度地区记录的末次冰期气候突变事件具有全球意义的新证据。 |
| 关键词: 冲绳海槽 古海洋 末次冰期 |
| DOI： |
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| 基金项目:中国科学院知识创新工程重要方向项目，KZCX3-SW-220号和国家自然科学基金重点项目，90411014号。 |
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| Sedimentary Record of Millennial-scale Paleoceanography Evolution since the Last Glaciation in the Okinawa Trough |
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LI Tiegang1, CHEN Jinxia1,2, ZHANG Deyu3, LIU Zhenxia3
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1.Institute of Oceanology, The Chinese Academy of Sciences;2.Graduate School of the Chinese Academy of Sciences;3.The First Institute of Oceanography，State Oceanic Administration
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| Abstract: |
| Piston cores CSH1 and DGKS9603 used in this study were collected from the Middle Okinawa Trough (31°13.733′N, 128° 43.471′E, water depth 703m and 28°08.869′N, 127°16.238′E, water depth 1100 m, respectively) during a China-France join t survey in the East China Sea. The palynologic assemblages of core CSH1 and plank tonic foraminifers investigated in this work, provide a direct historical record of paleo climate oscillations during the last 50 kyrs. A total of six cooling events were identified based on spore pollen assemblages of core CSH1, these cold events occurred at 4.1～4.6, 11.7～13.0, 15.4、23.2, 29.4 and 47.4 ka respectively. The plank tonic foraminiferal δ18O, faunal variations and MAT SST records of core DGKS9603 also show six cooling events during the last 50 kyrs, unlike core CSH1 these events occurred at 11.7～13.0, 14.7, 24.3, 28.5, 36.9 and 45.3 ka respectively. The cold events of the two piton cores show good correlation with the coldest stadials of Dansgaard-Oeschger cycles documented from the Greenland GR IP ice cores, δ18O record corresponding to the youngest five Heinrich events. Our study indicates that cold events (Younger Dryas event and the four Heinrich events H1, H2, H3, H5) shown by different palao environment investigative methods in different regions from the Okinawa Trough correlated well. Although the true climate teleconnections between the Okinawa Trough and Greenland and the North Atlantic is unclear, millennial to centennial fluctuations in the in tensity of the East Asian monsoon circulation induced by climate oscillations in the high latitudes of the North Hemisphere could be the main mechanism. |
| Key words: the Okinawa Trough the Last Glaciation Millennial-scale Paleoceanography Evolution |
