Core Description and Characteristics of Fault Zones from Hole-A of the Taiwan Chelungpu-Fault Drilling Project

Yeh, En Chao; Sone, H.; Nakaya, T.; Ian, Ka Hao; Song, Sheng-Rong; Hung, Jung Chou; Lin, Weiren; Hirono, Tetsuro; Wang, Chien Ying; Fong, Kuo; Soh, Wonn; Kinoshita, Masataka

doi:10.3319/tao.2007.18.2.327(tcdp)

Cited by 54 publications

(61 citation statements)

References 25 publications

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“…Several fault strands of the Chelungpu-fault system were crossed by TCDP Holes A and B (Fig. 2c) (Ye et al, 2007). The lowermost fault strand at a depth of 1111 m (Hole A) and 1136 m (Hole B) was identified as the principal slip zone (PSZ) associated with 1999 ChieChi earthquake (Ma et al, 2006;Kuo et al, 2013).…”

Section: The Tcdp Projectmentioning

confidence: 99%

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Janssen

Wirth

Wenk

et al. 2014

Journal of Structural Geology

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a b s t r a c tThe microstructures, mineralogy and chemistry of representative samples collected from the cores of the San Andreas Fault drill hole (SAFOD) and the Taiwan Chelungpu-Fault Drilling project (TCDP) have been studied using optical microscopy, TEM, SEM, XRD and XRF analyses. SAFOD samples provide a transect across undeformed host rock, the fault damage zone and currently active deforming zones of the San Andreas Fault. TCDP samples are retrieved from the principal slip zone (PSZ) and from the surrounding damage zone of the Chelungpu Fault. Substantial differences exist in the clay mineralogy of SAFOD and TCDP fault gouge samples. Amorphous material has been observed in SAFOD as well as TCDP samples. In line with previous publications, we propose that melt, observed in TCDP black gouge samples, was produced by seismic slip (melt origin) whereas amorphous material in SAFOD samples was formed by comminution of grains (crush origin) rather than by melting. Dauphiné twins in quartz grains of SAFOD and TCDP samples may indicate high seismic stress. The differences in the crystallographic preferred orientation of calcite between SAFOD and TCDP samples are significant. Microstructures resulting from dissolutioneprecipitation processes were observed in both faults but are more frequently found in SAFOD samples than in TCDP fault rocks. As already described for many other fault zones clay-gouge fabrics are quite weak in SAFOD and TCDP samples. Clay-clast aggregates (CCAs), proposed to indicate frictional heating and thermal pressurization, occur in material taken from the PSZ of the Chelungpu Fault, as well as within and outside of the SAFOD deforming zones, indicating that these microstructures were formed over a wide range of slip rates.

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Section: The Tcdp Projectmentioning

confidence: 99%

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Janssen

Wirth

Wenk

et al. 2014

Journal of Structural Geology

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“…More cultivated metabolisms derived from the thin layer of fault gauge than those from its host rocks at 690 mbls were consistent with this general consideration ( Table 2). The diversity of cultivable metabolisms for samples adjacent to the Chelungpu fault zone located at depths ranging from 1100 to 1220 mbls Song et al 2007;Yeh et al 2007), however, neither increased nor decreased significantly. It seemed to suggest that either the fluid circulation was limited within a relatively narrow range or the fault zone had no effect on enhancing the diversity of metabolisms.…”

Section: Correlation With Geological Parametersmentioning

confidence: 89%

Cultivation-Based Characterization of Microbial Communities Associated with Deep Sedimentary Rocks from Taiwan Chelungpu Drilling Project Cores

Wang¹,

Lin²,

Yu³

et al. 2007

Terr. Atmos. Ocean. Sci.

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ABSTRACT1 Institute of Oceanography, National Taiwan University, Taipei, Taiwan, ROC 2 Department of Geosciences, National Taiwan University, Taipei, Taiwan, ROC The Taiwan Chelungpu Drilling Project (TCDP) has provided an unprecedented opportunity to reveal a terrestrial subsurface microbial ecosystem that has possibly experienced continuous disturbance by the arccontinental collision since 5 Ma. The drilling penetrated Pliocene-Pleistocene sedimentary rocks to a depth of 2000 meters below the land surface (mbls) and encountered two major fault zones. Sixteen samples retrieved from the drilled cores at depths between 464 to 1451 mbls were examined to characterize microbial community structures through cultivation-based approaches. Cultivation experiments were performed with various media at temperatures ranging from 30 to 50°C. The results indicate that fermenters and heterotrophic sulfate reducers, using complex organic carbon, were ubiquitously present in most samples. Acetate-utilizing and H 2 -utilizing sulfate reducers were restricted to shallower intervals along the depth profile. Iron reducers and methanogens were only cultivated in a few shallow samples. Twelve pure strains including 8 fermenters, 3 iron reducers and Terr. Atmos. Ocean. Sci., Vol. 18, No. 2, June 2007 396 1 sulfate reducer originally enriched at 30 or 40°C were isolated and identified with 16S rDNA sequence analyses. They were phylogenetically affiliated with Firmicutes, Bacteriodes, Actinobacteria, and Proteobacteria in various degrees of similarity. The presence of metabolism was not correlated with lithology, depth, temperature and the appearance of fracture throughout the core. The ubiquitous appearance of fermentation and organotrophic sulfate reduction suggests that organic carbon sources were readily accessible in this deep terrestrial subsurface environment. These results infer that the foreland sedimentary strata disturbed by tectonic activities over a geological time scale might support a heterotrophy-dominated deep terrestrial subsurface microbial ecosystem.

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“…The drilling site is located in the vicinity of Taichung city in the central region of western Taiwan. In this main drilling hole all cores were continuously retrieved from a 500-m depth down to the maximum drilled depth of 2003 m. According to Yeh et al (2007), downward lithology column of Hole-A was identified as Cholan Formation (0 -1027 m, early Pleistocene-Pliocene), Chinshui Shale Formation (1027 -1290 m, early Pliocene), Kueichulin Formation (1290 -1710 m, early Pliocene-late Miocene), and Cholan Formation (1710 -2003 m) again. Thus, the depths from which the cores were taken for ASR measurements are in the shallower Cholan Formation, Chinshui Shale Formation, and deeper Cholan Formation, respectively.…”

Section: Rock Materials From Tcdp Hole-a and Preparation Of Specimensmentioning

confidence: 99%

“…In the depth range of Chinshui Shale Formation or around the boundary between Chinshui Shale and Kueichulin Formations, which was considered to be the possible depth range from teleseismic data of the earthquake, four fault zones were encountered in the depth range from 1111 to 1241 m. No certain scientific evidence(s) to identify which fault slipped during the earthquake has been obtained yet. However, many scientists believe that the fault zone located around 1111 m (FZA1111) is the most likely candidate of the earthquake faults the four fault zones Yeh et al 2007). A core sample taken from 1112 m located within the FZA1111, but at its deeper portion.…”

Section: Rock Materials From Tcdp Hole-a and Preparation Of Specimensmentioning

confidence: 99%

Preliminary Results of Stress Measurement Using Drill Cores of TCDP Hole-A: an Application of Anelastic Strain Recovery Method to Three-Dimensional In-Situ Stress Determination

Yeh¹,

Ito²,

Hirono³

et al. 2007

Terr. Atmos. Ocean. Sci.

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In order to understand the feature of rock stress change at different depths above, within, and beneath the Chelungpu fault after the Chi-Chi earthquake, we employed a core-based stress measurement method, anelastic strain recovery (ASR) technique to determine both the orientations and magnitudes of present three-dimensional principal rock stresses using drill core samples retrieved from Taiwan Chelungpu-fault Drilling Project (TCDP) main Hole-A. The core samples used were taken from three depths; and their lithology were sandstone at depths of 592 and 1755 m and siltstone at 1112 m. The anelastic strains of the specimens in nine directions, including six independent directions, were measured after its in-situ stress was released. Acquired anelastic strains were of high quality and reached several hundred microstrains, which is sufficiently high for the accuracy of the measurement system used. Thus, the strain data could be used for threeTerr. Atmos. Ocean. Sci., Vol. 18, No. 2, June 2007 380 dimensional analysis resulting in the determination of orientations and the estimation of magnitudes of the principal in-situ stresses. Preliminary stress measurement results showed that the orientations of principal stresses changed between the shallower depth above the fault and the deeper depth beneath it, that is, the present stress distribution in the TCDP hole might be influenced by the Chelungpu fault rupture. At the same time, anelastic strain recovery measurement is well suited for the task of directly determining the orientations of principal in-situ stresses and to estimate the magnitude of stresses at large/great depth.

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Core Description and Characteristics of Fault Zones from Hole-A of the Taiwan Chelungpu-Fault Drilling Project

Cited by 54 publications

References 25 publications

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Cultivation-Based Characterization of Microbial Communities Associated with Deep Sedimentary Rocks from Taiwan Chelungpu Drilling Project Cores

Preliminary Results of Stress Measurement Using Drill Cores of TCDP Hole-A: an Application of Anelastic Strain Recovery Method to Three-Dimensional In-Situ Stress Determination

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