碩士 / 國立中央大學 / 地球物理研究所 / 94 / Structures, physiography and development of the Penghu submarine Canyon off southwest Taiwan
Abstract
A seismic study was carried out on a dense grid of multi-channel seismic data off SW Taiwan. The study area can be divided into three geological domains on the basis of its structural and topographic characteristics: the South China Sea (SCS) continent -al slope domain, the frontal and Middle segments of the accretionary prism.
The deformation front and strikes of folds and thrusts trend in an NE-SW direction in the north and turn into an N-S direction toward the south whilst the numbers of emergent thrusts decrease. This feature may result from the oblique arc-continent collision. We divided five topographic and tectono-seismic facies on the basis of seafloor topography, structure types and seismic facies in the study area. They are continental-slope facies、submarine canyon erosion facies, fold facies, emergent thrust facies and basin facies, respectively. Seismic data shows upper slope of SCS (shallower 2000 m) is an erosive environment and the lower slope (deeper 2000 m) is an area of deposition. In acctetionary prism, the main depozone is in the slope basin whereas the tectonic ridges exhibit minor erosion. Zones of major erosion lie in the drainage areas of Penghu and Kaoping Canyons In accretionary prism, the main depozone is in slope basin (or piggyback basin).The structure uplift resulted in small-scale erosion in most region. The main erosion zone is in drainage of Peng-Hu and Kao-Ping canyon.
A series of longitudinal channel profiles in the SCS slope and accretionary prism was analyzed to reveal the interaction among tectonic development, sedimentation and erosion. We analyzed the main submarine canyon longitude section of SCS continental. In SCS continental slope, the channel profile resembles that of an exponential curve. The gradient of individual channel profile becomes greater as the channel approaches deformation front.
The gradient of Peng-Hu submarine canyon is gentle. The gradient has various Channel gradient of the Penghu submarine canyon, which lies in the acctetionary prism, is gentler then that in the SCS slope. The Penghu channel profile shows several step-like nickpoints corresponding to structural uplift. Finally, development of the Penghu can be divided into four stages by analyzing the timing of movement for individual structures and seismic facies.
| Identifer | oai:union.ndltd.org:TW/094NCU05134030 |
| Date | January 2006 |
| Creators | Gang-Yu Chen, 陳冠宇 |
| Contributors | Andrew Tien-Shun Lin, 林殿順 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
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