HR: 0800h
AN: T51A-1327    [Abstracts]
TI: Lithostratigraphy of the Taiwan Chelungpu-Fault Drilling Project-A borehole and its neighboring region, central Taiwan
AU: Lin, A T
EM: andrewl@cc.ncu.edu.tw
AF: Department of Earth Sciences, National Central University, No. 300 Jungda Road, Chungli, Taoyuan, 320 Taiwan
AU: Wang, S
EM: shaner24@geo.ncu.edu.tw
AF: Institute of Applied Geology, National Central University, No. 300 Jungda Road, Chungli, Taoyuan, 320 Taiwan
AU: * Hung, J
EM: jhung@earth.ncu.edu.tw
AF: Department of Earth Sciences, National Central University, No. 300 Jungda Road, Chungli, Taoyuan, 320 Taiwan
AU: Wu, J
EM: 048704@cpc.com.tw
AF: Chinese Petroleum Corporation, No.1 Dayuan, Wenfa Road, Miaoli, 360 Taiwan
AU: Wu, M
EM: 047295@cpc.com.tw
AF: Chinese Petroleum Corporation, No.1 Dayuan, Wenfa Road, Miaoli, 360 Taiwan
AU: Liu, C
EM: chihshae@ms.taneeb.gov.tw
AF: Taiwan Area National Expressway Engineering Bureau, 5F No.1 Ln.1 Hoping E. Rd. Sec.3, Taipei, 106 Taiwan
AB: A late Miocene to Pleistocene, shallow marine succession of 2003 meters in drill depth was drilled and cored at the TCDP (Taiwan Chelungpu-Fault Drilling Project)-A borehole. Stratigraphic framework of this borehole and its neighboring region is vital in understanding the complex subsurface geological structures and in what rock formations that the 1999 Chi-Chi earthquake rupture occurred both on the ground surface and at depth. To this end, we examined the core lithofacies and geophysical-log curves of this drill bore and established a stratigraphic succession for this well. The borehole stratigraphic succession was then correlated to the stratigraphy of the wells drilled by Chinese Petroleum Corporation (CPC) neighboring the TCDP-A well in central Taiwan. In addition, on the basis of stratigraphic analyses carried out on outcrops and 14 shallow (20-100 m in drill depths) boreholes in the region adjoining TCDP-A well, we constructed a vertical stratigraphic succession that represents the surface rock sequence whose equivalent strata were encountered at the TCDP-A well. This approach enables us to establish the stratigraphy of the TCDP-A borehole as follows (numbers are in drill depth with reference to wireline logs): (1) 0-1013 m: lower Cholan Formation; (2) 1013-1313 m: Chinshui Shale; (3) 1313-1707 m: Kueichulin Formation; (4) 1707-2003 m: Cholan Formation as judged from common occurrence of reworked Miocene nannofossils and similar lithology to the exposed Cholan Formation. Our results also find that the Chinshui Shale and older formations are not exposed to the west of the TCDP-A well, a view different from that shown in the geological map published by CPC. The Chi-Chi surface rupture occurs near the base of the Cholan Formation rather than in the Chinshui Shale as shown in the CPC geological map. Our data shows a previously unknown surface rupture that occurs 200-300 m to the west of the Chi-Chi surface rupture. This rupture offsets the unconformity between the terrace gravels and underlying tilted Pliocene strata.
DE: 8002 Continental neotectonics (8107)
DE: 9320 Asia
SC: Tectonophysics [T]
MN: Fall Meeting 2005