碩士 / 國立臺灣大學 / 海洋研究所 / 97 / The southwestern Taiwan offshore is mainly composed by narrow continental shelf with several submarine canyons, in which the Gaoping canyon is connected with the Gaoping River, and in contrary, the Fangliau canyon is without river connected. This study wishes to combine the grain size and 210Pb profile data in conjunction with X-radiograph images to understand the transportation of sediments on the shelf off southwestern Taiwan, especially in the Gaoping and Fangliau canyons.
X-ray radiography images show the turbidites are widespread in the study area, and grain size results show the sand contents are increased form upper canyon to lower canyon. It implies the sediments were transported by turbidity or gravity flow in this area. 210Pb analysis shows new turbidite layer in all the Gaoping canyon and western Fangliau canyon core samples. In the March of 2006, we collected a core (OR1-785-2A) from Gaoping canyon and found a newest forming thick turbidite in the box core. A year later, at the same location, a gravity core (OR1-851 GCC) was taken and finds the thickness of the turbidite layer is over 150 cm, and this turbidite layer is related to the flooding event in 2005. In the lower part of the gravity core OR1-785-2A, the thin layered turbidites are appeared repeatedly. We suggest the huge and thick sediments were deposited in the canyon in temporary, followed by long-term re-suspension, re-transportation and erosion processes, the thick turbidite layer transferred into thin layer, and the whole transformation illustrates why the submarine canyon is a conduit of sediments transportation. Compare to the Gaoping canyon, the new turbidites deposited in the Fangliau canyon was probably caused by the 2006 Hengchun earthquake.
| Identifer | oai:union.ndltd.org:TW/097NTU05274027 |
| Creators | Jing-Yi Tseng, 曾靜宜 |
| 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 | 76 |
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