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通过对冲绳海槽中部A7孔的浮游有孔虫定量分析,对该区18 ka以来的海洋环境变化进行了探讨.浮游有孔虫群落表现出非常明显的冰消期-全新世阶段变化:在18~15 ka的冰消期早期,浮游有孔虫群落以冷水种Neogloboquadrina duter-trei和Neogloboquadrina pachyderma等为主;在15~9.4 ka,浮游有孔虫冷水种含量迅速降低;9.4 ka以来的全新世则以暖水种有孔虫Pulleniatina obliquiloculata,Globigerinoides ruber和Globigerina glutinata等为主.此外,浮游有孔虫群落对千年尺度的气候变化如Heinrich 1、博令-阿罗德暖期(Bφlling-Allerφd)和新仙女木事件(Younger Dryas)都有明显反映,在全新世还记录了一系列的冷事件(约2.3~4.6、5.3、6.2、7.3和8.2 ka).9.4 ka前后浮游有孔虫冷暖种群的变化可能对应了黑潮暖流的突然加强.采用5种不同浮游有孔虫转换函数对表层海水温度进行了估算,通过与Mg/Ca和Uk3 7温度估算结果对比,对不同转换函数的可靠性进行了评估.结果发现SIMMAX没有明显的冰消期-全新世变化.另两种基于现代类比技术的转换函数MAT和RAM,其估算结果较类似,13 ka以来的温度波动较小,对新仙女木事件没有明显反映.基于Imbrie-Kipp转换函数(FP-12E和IKM-Chen)的估算结果表现出了较大的冰消期-全新世变化,然而对于博令-阿罗德暖期变暖和新仙女木降温事件没有反映,研究发现这主要由Globigerina bulloides的含量变化造成.通过消除与生产力水平密切相关的G.bul-loides的含量变化影响,修正后的两种转换函数FP-12E和IKM-Chen较好地反映了末次冰消期以来的表层海水温度波动,与该区Mg/Ca和Uk3 7方法重建的古温度有较好的可比性.因此,我们认为修正后的转换函数FP-12E和IKM-Chen更适合冲绳海槽中部的古温度估算.
The quantitative analysis of planktonic foraminifera in hole A7 in the central part of the Okinawa Trough explored the changes of the marine environment in the area since 18 ka. The planktonic and foraminifer community showed a very clear eclogation - a change in the Holocene: In the early period of 18-15 ka, the planktonic and foraminifer communities were mainly Neogloboquadrina duter-trei and Neogloboquadrina pachyderma. The contents of planktonic and foraminifer cold water species rapidly decreased from 15 to 9.4 ka, In the world, the dominant species are Pulleniatina obliquiloculata, Globigerinoides ruber and Globigerina glutinata, etc. In addition, the community of planktonic and foraminifera on the Millennium scale climate change such as Heinrich 1, Bölling-Alderφd ) And Younger Dryas, a series of cold events (about 2.3 ~ 4.6, 5.3, 6.2, 7.3 and 8.2 ka) were also recorded during the Holocene. The warm and cold of planktonic foraminifera The change of population may correspond to the abrupt increase of Kuroshio current.Using five different planktonic foraminifera transfer functions, the surface seawater temperature was estimated. By comparing with the temperature estimation results of Mg / Ca and Uk3 7, The results show that SIMMAX does not have obvious ice expiration-Holocene changes.The other two transfer functions MAT and RAM based on modern analogy techniques have similar estimation results, and the temperature fluctuations since 13 ka The results of the Imbrie-Kipp transfer function (FP-12E and IKM-Chen) showed a large change of ice age-Holocene, however, The results show that this is mainly caused by the content change of Globigerina bulloides.By eliminating the content change of G.bul-loides, which is closely related to the productivity, the two modified transfer functions FP-12E and IKM-Chen better reflect the temperature fluctuations of the surface seawater since the last deglaciation, which is in good agreement with the paleo-temperature reconstructed by the Mg / Ca and Uk3 7 methods in this area. Therefore, we think that after correction The conversion functions FP-12E and IKM-Chen are more suitable for the paleo-temperature estimation of the middle Okinawa Trough.