碩士 / 國立中央大學 / 地球物理研究所 / 100 / Taiwan is located in a convergent zone between the Eurasian Plate and the Philippine Sea Plate. This context makes the tectonics around Taiwan very active as exhibited by the numerous faults. Hengchun Peninsula in the southern part of Taiwan is part of the uplifted accretionary prism due to the arc-continent collision. The southern part of Hengchun Peninsula is also a very famous tourist spot known for its spectacular natural landscape and numerous watersports. Compared to the importance of the environmental assessment of this area, the bathymetric and structural features information in this area is quite rare.
In this study, we use multi-beam echo sounder (MBES), side-scan sonar (SSS), sub-bottom profiler (SBP) and the multi-channel seismic reflection system (MCS) data to analyze the seafloor structures and locate the offshore extension of the Hengchun Fault in the south of the Hengchun Peninsula.
In the eastern portion of the study area, a series of high-angle unconformities exhibiting apparent dislocation in the sedimentary layers are observed in the two SBP profiles. These structures are inferred to be portions of a fault zone or shear zone, and maybe related to the Hengchun Fault. The distance between the faults in the SBP profiles and the onland Hengchun Fault is about 5.2 km, but no similar signal is observed in the rest of the 6 SBP profiles in between. According to those previous data, we suggest that the east part of South Bay is a pull-apart basin which cause by the negative flower structure at the southern offshore extension of the Hengchun Fault.
There are a series of dune structures in the middle part of the study area which can be observed in the MBES and SSS data. The water depth at the area where dune structures occurred ranges from 100 to 160 m. The height and the length of dunes increase with water depth. The gentle slope of the dunes clearly shows the direction of the bottom current.
Incised valley and offlap sequence were found in SBP profiles at the northern section of the east side of South Bay Channel. These seafloor features imply that this area had experienced a sea level drop event before, which might correspond to the last glacial maximum about 10,000 years ago.
| Identifer | oai:union.ndltd.org:TW/100NCU05134018 |
| Date | January 2012 |
| Creators | Kuan-Ting Lin, 林冠婷 |
| Contributors | Shu-Kun Hsu, 許樹坤 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 118 |
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