蘇志杰Su, Chih-Chieh臺灣大學:海洋研究所張嫚珊Chang, Man-ShanMan-ShanChang2010-05-062018-06-282010-05-062018-06-282008U0001-1507200802255400http://ntur.lib.ntu.edu.tw//handle/246246/181188本研究利用ORI-790之7管箱型岩心及ORⅢ-1166之23個表層沉積物，分析其粒徑分布、超量210Pb活度剖面及X光攝影結果，加上連續變頻聲納對於砂波的探測資料，期望能了解台灣海峽沉積物之來源及傳輸途徑。徑分析結果顯示，台灣海峽沉積物中的粗、細顆粒物質分別代表著不同的來源。台灣近岸的粗砂，為台灣輸出的現代沉積物；有別於近岸粗顆粒沉積物，海峽中的細砂則是受到潮流作用侵蝕澎湖水道後搬運至彰雲沙脊的老沉積物，而後此細砂沉積物再經由潮流作用持續往北傳輸，與泥質沉積物混合；至於以往被認為是由中國沿岸流攜帶而來的泥質沉積物，則可能部分源自於台灣西部河川的輸出。較過量Pb-210及Cs-137所計算出之沉積速率，可知台灣海峽沉積物深受混合作用的影響。而位於澎湖水道及彰雲沙脊地區存在許多大型砂波，亦說明此地流速強烈、易造成沉積物之再懸浮與混合作用。另外由ORI-790 BC5岩心之X光影像可看出具有交錯層理構造，推論此地主要是受到潮流往復作用的影響，造成沉積物混合強烈。合言之，台灣海峽屬淺海陸棚區，潮流在此扮演著侵蝕與搬運沉積物的角色；以沉積動力的角度觀之，台灣海峽沉積物屬現代潮流沉積系統的一部份。而台灣海峽沉積物應包含來自台灣西部河川所輸出的現代沉積物，藉由海流作用向北傳輸，並與老的潮流沉積物混合、沉積所形成。In this study, 7 box cores and 23 surface sediment samples were collected by using ORI-790 and ORIII-1166 cruises in the Taiwan Strait. Grain size analysis, in conjunction with 210Pbex, and X-ray radiographs results have been used to identify the sources, transportations and deposition of the sediments.he grain size result shows the sediments in the Taiwan Strait may classify into three different types. For coarse sand sediments in the nearshore area of Taiwan are modern sediments exports from the rivers in the western Taiwan. The fine sand sediments in the central Taiwan Strait are the aged sediments which influenced by tidal current in the Taiwan Strait and deposited in the Changyun Ridge. Afterwards, these fine sand sediments will transport northward and mix with mud sediments. For the mud sediments located at the Kuanyin Depression which were considered from mainland China may reconsidered as the products of the western Taiwan rivers.omparing the sedimentation rates which calculated from the excess Pb-210 and Cs-137 profiles, the sedimentation processes in the Taiwan Strait are highly influenced by the resuspension and mixing processes. This inference is also supported by the existing of large to very large sand waves occur on the Changyun Ridge and the Penghu Channel regions. In core ORI-790 BC5, we may see the development of the cross-bedding in the X-radiographic image. It suggests that the mixing process in the Taiwan Strait are mainly caused by the tidal currents.n summary, with the erosion and movement of the sediments influenced by tidal currents, the Taiwan Strait may be considered as a modern tidal deposition system. The sediments in the central Taiwan Strait are composed by the coarse sediments from the Changyun Ridge and the fine sediments from western Taiwan.中文摘要...................................................i文摘要..................................................ii錄......................................................iv目錄...................................................vii目錄.....................................................x一章 緒論...............................................1.1 前言...................................................1.2 研究區域背景...........................................2.2.1 海底地形.............................................3.2.2 水文流場.............................................5.3 前人研究...............................................7.3.1 台灣海峽沉積物特性與分布.............................8.3.1.1 殘餘沉積物的定義..................................13.3.1.2 變餘沉積物的定義..................................14.3.2 台灣海峽之沉積作用..................................14.3.3 台灣海峽沉積物傳輸方向..............................17.3.3.1 砂波地形..........................................17.3.3.2 粒徑趨勢分析......................................20.3.4 台灣海峽沉積物之來源................................21二章 研究方法..........................................23.1 研究區域..............................................23.2 採樣方法及分析步驟....................................25.2.1 聲納系統地形探測....................................26.2.2 沉積物採樣..........................................27.3 砂波地形分析..........................................28.4 沉積物分析............................................28.4.1 X光攝影............................................29.4.2 粒徑分析............................................31.4.3 含水率測定..........................................37.4.4 燒失量測定..........................................38.4.5 210Pb放射化學分析...................................38三章 實驗結果與討論....................................44.1 沉積物粒徑分析........................................44.1.1 ORI-790表層沉積物粒徑分析...........................44.1.2 ORⅡ-1294（彰雲沙脊）表層沉積物粒徑分析.............46.1.3 ORⅢ-1166（濁水溪口）表層沉積物粒徑分析.............50.1.4 台灣西岸輸出沉積物之短期傳輸........................54.2 砂波地形分析..........................................57.3 岩心X光攝影...........................................60.4 210Pb放射化學分析.....................................61.5 岩心X光影像、粒徑、210Pb隨時間（深度）之變化..........63.6 綜合討論：台灣海峽沉積物之來源及其傳輸途徑............65.6.1 台灣海峽沉積物特性與分布............................66.6.2 台灣海峽之沉積作用..................................66.6.3 台灣海峽沉積物傳輸方向..............................67.6.4 台灣海峽沉積物之來源................................67四章 結論..............................................70考文獻..................................................72錄I.....................................................78錄Ⅱ....................................................82application/pdf10999528 bytesapplication/pdfen-US台灣海峽粒徑分析Pb-210殘餘沉積物潮流沉積物Taiwan Straitgrain size analysisrelict sedimenttidal current sedimentthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/181188/1/ntu-97-R95241301-1.pdf