摘要
通过对冲绳海槽中部A7孔的浮游有孔虫定量分析，对该区18ka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18-15ka的冰消期早期，浮游有孔虫群落以冷水种Neogloboquadrina dutertrei和Neogloboquadrina pachyderma等为主；在15～9．4ka，浮游有孔虫冷水种含量迅速降低；9．4ka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（Bolling-Allerod）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8．2ka）．9．4ka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U37^k＇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没有明显的冰消期一全新世变化．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，13ka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.bulloides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U37^k＇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．
Quantitatively analyzed planktonic foraminiferal data of core A7 were used to discuss the paleoenvironmental changes in the middle Okinawa Trough during the past 18 000 years. The planktonic foraminiferal fauna shows apparent changes corresponding well to the deglaciation-Holocene phases： At about 18-15 ka, the fauna was dominated by cold water species such as Neogloboquadrina dutertrei and Neogloboquadrina pachyderma ; Cold water species decreased rapidly hetween 15 - 9. 4 ka; After 9. 4 ka the fauna was dominated by warm water species such as Pulleniatina obliquiloculata, Globigerinoides tuber and Globigerina glutinata. Millennial-scale climate changes during the last deglaciation such as Heinrich 1 （H1）, Bolling-Allerod （B/A） and Younger Dryas （YD） were also recorded by planktonic foraminiferal changes, it also shows a series of cold events （at about 2.3-4. 6, 5.3, 6.2, 7.3, 8. 2 ka） superimposed on a Holocene warming trend. At about 9.4 ka, a sudden change in the relative abundance of warm to cold planktonic foraminiferal species probably indicates a sudden strengthening of the Kuro shio Current in the Okinawa Trough. Five foraminiferal transfer functions were used to estimate the paleo sea-surface temperature （SST） in core A7, through comparisons with SST estimates from two independent methods （U37^k＇ and Mg/Ca-based SST）, and the reliability of different foraminiferal transfer functions were evaluated. Our results suggest that SIMMAX doesn＇t show apparent deglaciation-Holocene SST changes. The other two transfer functions （MAT and RAM）, which are also based on modern analog techniques as SIMMAX, both show small SST variations after 13 ka, without any indication of decreased SST during the YD period. Transfer functions FP-12E and IKM-Chen based on Imbrie-Kipp method, show general deglaciation- Holocene SST trends similar to U37^k＇ and Mg/Ca-based SST, however, the deglacial warming is about 1 ka later than the B/A warming, and with no apparent SST decreases during the YD p
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2011年第4期599-609,共11页
Earth Science-Journal of China University of Geosciences
基金
海洋沉积与环境地质国家海洋局重点实验室开放课题(No.MASEG200611)
国家重点基础研究发展计划(No.2010CB428901)
中国科学院知识创新工程资助项目(Nos.KZCX2-YW-211,KZCX2-YW-228)
国家自然科学基金项目(No.40976031)
关键词
沉积物
海洋地质
转换函数
表层海水温度
sediments
submarine geology
transfer function
sea-surface temperature.
