HR: 1340h
AN: T43B-1333    [Abstracts]
TI: Holocene vertical tectonic movements of the Taipei Basin, northern Taiwan and its implications
AU: * Chen, B
EM: b6204013@hotmail.com
AF: Department of Geosciences, National Taiwan University, No.1, Sec. 4, Rd. Roosvelt, National Taiwan University. Dept. of Geosciences, Taipei City, 106, Taiwan
AU: Hsieh, M
EM: mlhsieh@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No.1, Sec. 4, Rd. Roosvelt, National Taiwan University. Dept. of Geosciences, Taipei City, 106, Taiwan
AU: Lai, T
EM: hua@moeacgs.gov.tw
AF: Central Geological Survey, Ministry of Economic Affairs, No.2,Lane 109,Huasin St.,Jhonghe City,Taipei County 235,Taiwan(R.O.C), Taipei County, 235, Taiwan
AU: Liew, P
EM: liewpm@ntu.edu.tw
AF: Department of Geosciences, National Taiwan University, No.1, Sec. 4, Rd. Roosvelt, National Taiwan University. Dept. of Geosciences, Taipei City, 106, Taiwan
AB: Many geological data of the Taipei Basin, although, have been published by various studies in past decades, however, vertical tectonic movement rate of the Basin was not well understood so far. This study, therefore, used radiocarbon dates, obtained from fifteen boreholes in the Basin, to calculate the Holocene vertical tectonic movement rate. In addition to the derived tectonic movement rate, this study also discussed the causes of the tectonic patterns of the Taipei Basin. The Taipei Basin, located in the northern Taiwan, was a half graben subsided and extended along the western boundary, the Shangiao Normal Fault, of the Basin. The Holocene vertical tectonic movement rate of the Basin were calculated based on 94 radiocarbon dates in fifteen boreholes, the elevations of the radiocarbon dating samples, and the eustatic sea-level curve of the past 15 ka. The results showed the rate in the western part of the Basin, was -2.2 — -0.9 mm/yr (negative value indicates subsiding, and positive value indicates uplifting). In the central part of the Basin, the rate was ca. -1 — 1 mm/yr while in the eastern part of the Basin, the rate was 0.1 — 1.6 mm/yr. Along the Shiangiao Fault, the rate of the hanging-wall was ca. -1.6 — -0.4 mm/yr and the rate of the footwall was ca. 0 mm/yr. According to the results of this study, the present territory of the Taipei Basin was not actually consistent with the tectonic subsiding region. The vertical tectonic movement pattern demonstrated subsidence in the western part and uplift in the eastern part of the Taipei Basin. The subsidence of the western part was controlled by the extension of the Shangiao Faul. The uplift of the eastern part might be ascribed to the roll-over of the Fault. Another possibility is that the uplift of the east was controlled by the same behavior as the Western Foothills.Consequently, the deposition of the eastern part of the Basin, wass mainly related to the accommodations due to sea-level rise but not tectonic subsidence.
DE: 1641 Sea level change (1222, 1225, 4556)
DE: 1861 Sedimentation (4863)
DE: 8175 Tectonics and landscape evolution
SC: Tectonophysics [T]
MN: 2007 Fall Meeting