碩士 / 國立中山大學 / 海洋科學系研究所 / 104 / The Taiwan Strait, which connects two mainly marginal seas of the Asia, the East China Sea and the South China Sea, is not only the sink of riverine sediments from Taiwan Island and Mainland China, but also a possible transporting route of sediments between two marginal seas. Taiwan Strait is distinguished with Taiwan Shoal, Chan-Yuen Rise, Penghu Channel, Kuan-Yin Depression, and Wu-Chiu Depression, which makes it become a complicated area for sediment deposition. In published researches, we have known that part of the sediments come from the Pearl River will transport north toward the Taiwan Strait by SCS Warm Current. However, the shallow Taiwan Shoal with merely 20-40 meters in water depth may block the sediment transportation leading to the absence of modern sediments to be reached and deposited. Therefore, the relict sediments left since last glacial period because of the fallen sea-level are main composition over the shoal. Sediments contribute from Taiwan Island via the Kaoping River principally enter the SCS basin through Kaoping Canyon. Otherwise, some suspended particles might be transported northward through Penghu Channel carried by Kuroshio branch flow. As a result, Zhuoshui River discharged sediments might precipitate at Chan-Yuen Rise and Kuan-Yin Depression. Furthermore, some studies also suggest that part of the fine-grained sediments discharging from northeastern Taiwan Strait can reach the southern Okinawa Trough. Most of Yangtze River discharged sediments will deposit firstly at the delta area, then the others will flow southward along China coast then form the mud belt in central Taiwan Strait which mixing with fine-grained sediments by Taiwan mountainous rivers.
Our results and published studies refer that grain size distribution curves and mean sizes can be used to indicate sediment transport pathway and the sources, and the two major factor affecting sediment distribution are ocean current and sediment sources. However, the spatial distribution and geochemical characteristics of surface sediments in the Taiwan Strait are rarely known. In this study, organic components, major and trace elements of surface sediments collecting from the Taiwan Strait are analyzed for tracing sediment sources and distinguishing transporting routes. TOC distribution shows the same as mean grain-size in this study, which means TOC is also influence by current system. Considering element at river mouth has low correlation with mother rock, it’s not indicative for the difference between river mouths. Therefore, we use element ratio normalized by Al content to indicate terrestrial contribution. Our results shown that Cs/Al、Ni/Al、Sn/Al、Ti/Al、Ba/Al、K/Al、Rb/Al、Tl/Al are good indicator for terrestrial sediment transportation by current system. In element ratio’s distribution, terrestrial sediments from Pearl river is hard to go throught Taiwan Shoal. On the other hand, sediments from Yangtze river can’t get throught Taiwan Shoal, either.
| Identifer | oai:union.ndltd.org:TW/104NSYS5276021 |
| Date | January 2016 |
| Creators | Chih-Yung Lin, 林之詠 |
| Contributors | Yuan-pin Chang, 張詠斌 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 134 |
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