碩士 / 國立中央大學 / 地球物理研究所 / 93 / A seismic interpretation study was carried out on a dense grid of multichannel seismic data off SW Taiwan. The study area can be divided into three geological domains on the basis of structure and sedimentary characteristics: the South China Sea (SCS) continental slope domain, the folded domain, and the thrusted domain. The folded and thrusted domains occupy the frontal accretionary prism.
The SCS continental slope domain situates between the Taiwan Strait shelf break and the deformation front of the accretionary prism. There are many erosional gullies in the upper slope of this domain, manifesting an erosion dominant region. Beneath the upper slope, the strata are eroded and truncated at the seabed, exposing Pliocene-Pleistocene sediments that are deeply buried in the adjacent shelf. By contrast, in the lower slope, there has developed slope-front fills revealing a deposition dominant region.
The region between the deformation front and the fringe of emergent thrusts is the folded domain. Several west-vergent blind thrusts have uplifted the strata and formed a series of anticlines. Seismic facies suggests that the western half of this region is dominated by hemipelagic sedimentation and the eastern half is dominated by the chanelling and deposition of the Penghu submarine canyon system.
The thrusted domain lies in between the westernmost emergent thrusts and the Kaoping Canyon. Westward emergent thrusts and anticlines prevail in this area. On top of each thrust sheets, it has developed a slope basin. Seismic facies show that the sedimentation is governed by hemipelagic sediments and/or turbidite deposits. Sedimentation in the eastern half of this region is influenced by the Kaoping and Kaohsiung submarine canyons as evidenced by turbidite levee deposits, channel and canyon infills.
In each thrust or anticline, there is an array of unconformities associated with the episodic development of the growing structures. An analysis of the timing for the development of these unconformities suggests that thrusts in the rear of the frontal prism occurred earlier (about 2.3Ma) than that in the region near the deformation front. Thrust activities were frequent in the thrust domain when compared to the folded domain.
Bottom simulating reflectors(BSRs), marking the base of hydrate stability zone, exist in the region deeper than c.600m and are commonly observed in thrusted domain, whereas it is less commonly found in the folded domain. The sub-bottom depth of the BSRs increases with icreasing water depths, a characteristic which is governed by the phase diagram of hydrate stability.
| Identifer | oai:union.ndltd.org:TW/093NCU05134020 |
| Date | January 2005 |
| Creators | Che-Chuan Lin, 林哲銓 |
| 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 | 152 |
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