碩士 / 國立臺灣大學 / 海洋研究所 / 96 / 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.
The 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.
Comparing 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.
In 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.
| Identifer | oai:union.ndltd.org:TW/096NTU05274009 |
| Date | January 2008 |
| Creators | Man-Shan Chang, 張嫚珊 |
| Contributors | Chih-Chieh Su, 蘇志杰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 83 |
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