魏國彥臺灣大學:地質科學研究所李文心Lee, Wen-HsinWen-HsinLee2010-05-112018-06-282010-05-112018-06-282008U0001-2501200815553400http://ntur.lib.ntu.edu.tw//handle/246246/182833國際古海洋全球變遷計畫(IMAGES)於2001年在西太平洋鑽取了一系列的深洋岩芯，期望可解析晚第四紀以來千年尺度的古海洋環境變化。沖繩海槽位處黑潮主流流經的地理樞紐，本研究利用取自南沖繩海槽MD012403岩芯的碎屑沉積物的粒徑分佈、黏土礦物及主要元素的組成，探討三萬年來黑潮流徑的變遷，以及沉積物供應來源變化。MD012403岩芯位於沖繩海槽的西南端 (25° 03.90'' N，123° 16.94'' E)，沉積物以陸源碎屑物為主，海源生物殼體次之；相對於其他深洋岩芯而言，本岩芯擁有較高的沉積速率(每千年50-500 cm)。D012403岩芯細粒沉積物的粒徑中值在20-32.6 ka時為7.3-7.8 Φ，較10.1-20 ka為細；10.1 ka以後，沉積物有變粗並伴隨著淘選度變差的趨勢，這樣的粒徑變化與可淘選粉砂(sortable silt)含量的增高指示著黑潮在此時進入了沖繩海槽。灣北部沉積物黏土礦物的Chlorite / Kaolinite值(>5)遠遠高於東海陸棚(<2)，本研究中岩芯沉積物在0-12 ka的Chlorite / Kaolinite值(2-6)高於12-21 ka的Chlorite / Kaolinite值(0.5)，推論12-21 ka東海陸棚為南沖繩海槽沉積物主要供應來源。灣沉積物與東海陸棚物質在主要元素K2O/TiO2比值上也有明顯差距，台灣沉積物的K2O/TiO2會高於東海陸棚的值，本研究中K2O/TiO2值(4.5)在12-21 ka遠遠低於0-12 ka及21-32.6 ka時的6-6.5，和黏土礦物變化趨勢一致，在12-21 ka時，東海陸棚物質輸入遠大於台灣東北部的貢獻。High sedimentation rates (50-500cm/kyr) in the South Okinawa Trough (SOT) provide high resolution records for reconstructing millennial or centennial paleo-environment changes. This research analyzes the grain size distribution , clay mineral assemblage and major elements of the IMAGE Core MD012403 retrieved from the Southern Okinawa Trough.he medians of grain size in MD012403 varied from 7.3 Φ to 7.8 Φ during 32.6 ka-20 ka and showed a coarsening trend during 21 ka-10.1 ka. After 10.1 ka, the grain sizes increased to 6.6-7.1 Φ were more stable in association with poor sorting. High content of sortable silt also occurred at this period, indicating the intensity of Kuroshio current was enhanced. he average chlorite / kaolinite ratio of detrital sediments from Taiwan (5.0) is much higher than that from the East China Sea Continental (ECS) Shelf (<2.0). The ratio of chlorite / kaolinite in Core MD012403 shows high values (2-6) during 0 ka-12 ka and maintains low (0.5) between 12 ka-21 ka. This suggests that the ECS may be the major sedimentary provenance during 12 ka-21 ka. oncentrations of MnO、CaO、MgO、ΣFe2O3 in sediment increase with depth but Na2O displays an opposite trend. Aoki and Oinuma(1974) documented that the sediments come from East China Shelf have a significantly low K/Ti ratio. In this study, the ratios of K/Ti drop down during 12 ka-21 ka indicating sources of sediments were mainly from ECS shelf. This interpretation is consistent with evidence also supports the inference derived from clay mineral assemblage.摘 要 I 錄 IV目錄 VI目錄 VII一章 緒論 1.1、沖繩海槽環境背景 1.2、黑潮 3.3、沉積物供應源區 3.4、年代模式與沉積速率 4.5、研究目的與方法 6二章 實驗方法 7.1、岩芯標本採樣 7.2、粒徑分析 8.3、黏土礦物分析 9.4、主要元素分析 10三章 岩芯沉積物之黏土礦物組成 13.1、黏土礦物概述 13.2、MD012403中黏土礦物相對含量變化 14.3、MD012403沉積物源區變化探討 16四章 岩芯沉積物中主要元素含量分析 19.1、主要元素含量變化 19.2、從主要元素探討沉積物源區變化 25五章 岩芯沉積物之粒度與其隱示之意義 27.1、沉積物之粒度分析 27.2、粒徑粒度分析與古黑潮 27六章 結論 30考文獻 32application/pdf2521927 bytesapplication/pdfen-US沖繩海槽黑潮黏土礦物粒徑分析主要元素分析Okinawa TroughKuroshioclay mineralsgrain size analysismajor elementsthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/182833/1/ntu-97-R93224114-1.pdf