博士 / 國立臺灣大學 / 海洋研究所 / 101 / Using reflection seismic profiles, this study investigates the forebulge migration in the Western Taiwan Foreland Basin (WTFB), the seismic facies of the synrift sequences of the Chaoshan Depresion, and discusses their implications for basin evolution of northern continental margin, South China Sea. The seismic characteristics in the sections across the forebulge of the WTFB displays a series of westwards overstepping unconformities, suggesting that the forebulge of the WTFB has migrated westwards since the Late Miocene. There are at least two episodes of migration of the forebulge of the WTFB. Four seismic facies are identified in the synrift sequences of the Chaoshan Depression: the Seismic Facies I (parallel-subparallel), the Seismic Facies II (chaotic), the Seismic Facies III (offlap), and the Seismic Facies IV (mounded). The Seismic Facies I and the Seismic Facies II are interpreted as the deposits formed during rift initiation of the Chaoshan rifting basin. The Seismic Facies III is interpreted as the deposits formed during rift climax of the rift basin. The Seismic Facies IV is interpreted as the deposits formed during immediate post rift of the rift basin. The parallel-subparallel reflectors in the Seismic Facies I may represent the deposits of a lacustrine environment and the chaotic reflectors in the Seismic Facies II may represent the lateral discontinuity of the sediments. Offlap reflections in the Seismic Facies III may
represent the progradation of deltaic sedimentary sequences in a marginal marine environment. Mounded reflectors in the Seismic Facies IV may represent the sedimentary lobes of a deep sea fan, deposited in a lower slope-basin floor environment.
The spatial-temporal distributions of the WTFB and the Chaoshan Depression provide implications for basin evolution of northern continental margin of the South China Sea. In the Paleogene, a series of rifting basins with a NE-SW trend occurred on the northern continental margin of the South China Sea, including the Chaoshan Depression and the Tainan Basin. The rifting of these basins has ceased at the Early Miocene, and following post-rift sedimentary sequences are deposited onto the rifting sequence of these basins. Since the Pliocene, the oblique collision between the Luzon arc and the Chinese continental margin has formed the Taiwan orogenic belt at the
northernmost part of the Northern continental margin of the South China Sea. The load of the Taiwan orogenic belt and the flexure of the Eurasian Plate resulted in the development of the WTFB and had influence on the development of the Tainan Basin since the Late Miocene. The central part of the WTFB has become a "mature" foreland basin and has received sediments derived from the Taiwan orogenic belt. On the other hand, the Kaoping Slope(SW Taiwan) and the Tainan Basin are currently considered to be "immature" foreland basins which are suffered from less tectonic(flexural) influence by orogenic load. Southwards, the Chaoshan Depression is not influenced by the load of the Taiwan orogenic belt, and preserves the configuration of a post-rift basin. The variations in tectono-stratigraphic characteristics of the basins (ie., the WTFB, the Tainan Basin, and the Chaoshan Depression) along the northern continental margin of the South China Sea suggest that the development of these basins are influenced by the
flexure of the Eurasian Plate in the Taiwan region. The progressive changes of basin configurations from a post-rift basin on the Chinese passive margin (the Chaoshan Depression), in transition to an "immature" underfilled foreland basin (the Tainan Basin), to a "mature" filled foreland basin (the WTFB) are reflected by the accompanying progressive changes from rifting in transition to initial collision and to arc-continent collision in Taiwan.
| Identifer | oai:union.ndltd.org:TW/101NTU05279007 |
| Date | January 2013 |
| Creators | Jih-Hsin Chang, 張日新 |
| Contributors | Ho-Shing Yu, 俞何興 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 112 |
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