本研究分析沖繩海槽中部的沈積物岩心MD012404中的有機化合物，包含不飽和烯酮類和長碳鏈奇數碳正烷類等，並藉由這些有機化合物重建東海過去10萬年沖繩海槽的古環境與古氣候變化。
由過去10萬年來的古海洋表水溫度研究顯示，東海的表面水文環境變化在軌道力週期的時間尺度上，主要受到全球氣候系統的冰期/間冰期變化所控制；而在千年時間尺度的變化中，只有在最近2萬年內，可以看見末次冰期回暖事件(Bølling-Allerød)和新仙女木事件(Younger Dryas)等氣候變化幅度較大的事件。而在北半球高緯地區快速變冷的Heinrich事件上，東海的海表溫度變化大都小於0.5℃(H1除外)，顯示這些快速變冷的氣候事件除了造成東亞冬季季風系統的增強外，對海表溫度的影響並不明顯。而由不飽和烯酮類濃度所指示的過去海洋表面生產力記錄來看，冰期時的東海生產力會高於間冰期，顯示冰期時由於風力增強驅動水團上下混合均勻或是貧營養鹽的黑潮水流量減少，導致大量的營養鹽輸入到東海的表水環境，造成海表生產力的增加。然而在7萬年前時可能由於東海的海表生產力有最大值的表現，因此在MIS 5的間冰期中，海表環境及控制因子較為複雜，與冰期/間冰期濃度變化的長期趨勢有所不同。
可以反映陸地植被影響的正烷類中長碳鏈奇數碳優勢，顯示沖繩海槽的沈積環境長期受到陸源物質輸入的影響。而在本研究中，奇數碳正烷類的優勢物種(Cmax)主要為C31，而奇數碳有機化合物優勢物種的濃度大小依次為C31>C29>C33>C27>C25，與長江輸出的陸源物質相同，顯示沖繩海槽中的陸源有機物質其主要來源應是來自於受長江輸出沈積物控制的東海陸棚區。而由碳優指數的記錄可以看出，在冰期時有較高值的表現，暗示冰期時陸源的有機物質受到降解作用的程度較小，顯示當全球海平面下降時，由於長江古河口較接近沖繩海槽，因此沈積物的搬運途徑減小，從長江河口輸出後會直接沈積在沖繩海槽中。從碳優指數、烷烴指數和C31/C27比值顯示，冰期時所得到的數值較高，表示在此時期由於氣候屬於乾冷氣候，因此陸地上的植被形態以草類為主。

In this study, concentrations of organic biomarkers of core MD012404, recovered from central part of the Okinawa Trough, were analyzed, included of unsaturated alkenones and n-alkanes, for reconstructing paleoenviromental and paleoclimatic records for the past 100,000 years.
The unsaturated alkenone index of Uk′37 were calculated for reconstructing past variations of sea surface temperature (SST) in the East Chna Sea (ECS). Through the past 100,000 years, our record revealed that the varied pattern of paleo-SSTs of the ECS was mainly reflecting Interglacial/Glacial cycles. This result indicates that the enhanced East Asian winter monsoon which is induced by the changing orbital forcing is the dominant controlling factor to influence the hydrological conditions in the ECS. Otherwise, except of the warming event of Bølling-Allerød and cooling event of Younger Dryas, no obviously cooling trends were observed in the record indicating that the Uk′37 based SST was not sensitive to the millennial-scaled climate events. This may be caused by the slow response of the SST to the millennial-sclaed events. The concentrations of unsaturated alkenones reconstructed in this study can represent to the surface productivity of the ECS. Our record shows that the values are higher in glacial period than in interglacial period. The higher productivity observed in glacial period may result from the wind-driven water mixing. Therefore, the well-mixing of surface and subsurface water thus can supply higher nutrients upto the surface water than induce the higher productivity in glacial period in the ECS. However, a more complicated pattern is found in MIS 5, the unsaturated alkenones have extremely high values in this interval which is different to the Holocene even though that the climatic conditions and global sea level are similar in these two periods. These high values may be caused by either higher surface production or well preservation, which results from the pool ventilation in the ECS.
In addition, distributed pattern of n-alkanes can represent to the possible sources of organic materials and vegetation changes on land. Our record shows that n-C31 alkane is dominant in n-alkanes, and the distribution pattern of n-alkanes (C31 > C29 > C33 > C27 > C25 ) is similar to the sediments discovered on the continental shelf of ECS and the estuary of the Changjiang River and is different with the sediments from the Lanyang Hsi River. This fact indicates that the organic materials buried in sediments of the Okinawa Trough are mainly contribute from the ECS continental shelf and the Changjiang River is serves as the main contributor of terrestrial sediments in the study region. Our calculated Carbon preference index (CPI) indicates that terrigenous orangic matters are less influenced by degradation and diagenesis in glacial period, especially during LGM, and the changing pattern is highly correlated with the global sea level changes. Lower sea level observed in glacial period shorten the transporting distance of sediments from the Changjiang River to the Okinawa Trough thus causes more terrestrial inputs and deposits in the Okinawa Trough.

致謝…………………………………………………………I
摘要…………………………………………………………II
Abstract……………………………………………………IV
目錄…………………………………………………………VI
表目錄……………………………………………………VIII
圖目錄………………………………………………………IX
附錄………………………………………………………...X

一、緒論……………………………………………………1
1-1 前言……………………………………………………1
1-2 研究區域………………………………………………1
1-3 區域水文環境…………………………………………4
1-4 文獻回顧………………………………………………8
1-4-1不飽和烯酮類……………………………………11
1-4-2長碳鏈正烷類……………………………………15
1-5 研究目標……………………………………………17
二、研究材料與方法……………………………………18
2-1 研究材料……………………………………………18
2-2 年代模式……………………………………………18
2-3 分析方法……………………………………………19
2-3-1 生物指標實驗前處理…………………………19
2-3-2 GC分析方法……………………………………22
2-4 資料分析……………………………………………23
2-4-1 分析長碳鏈正烷類………………………………23
- 2-4-2 分析不飽和烯酮類……………………………24
三、研究結果……………………………………………26
3-1 資料整合……………………………………………26
3-2 不飽和烯酮類………………………………………31
3-2-1不飽和烯酮類濃度………………………………31
3-2-2 古海洋表水溫度…………………………………33
3-3長碳鏈正烷類…………………………………………35
四、討論…………………………………………………37
4-1 沖繩海槽的古海洋表水紀錄比較…………………37
4-2 表層生產力紀錄……………………………………43
4-3 陸源有機物質含量…………………………………46
4-3-1 沉積物的來源……………………………………48
4-3-2 環境變化指標……………………………………50
4-3-3 氣候變化指標……………………………………52
五、結論…………………………………………………54
參考資料…………………………………………………56

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