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Titel |
Characteristics of chlorites in seismogenic fault zones: the Taiwan Chelungpu Fault Drilling Project (TCDP) core sample |
VerfasserIn |
Y. Hashimoto, O. Tadai, M. Tanimizu, W. Tanikawa, T. Hirono, W. Lin, T. Mishima, M. Sakaguchi, W. Soh, S. R. Song, K. Aoike, T. Ishikawa, M. Murayama, K. Fujimoto, T. Fukuchi, M. Ikehara, H. Ito, H. Kikuta, M. Kinoshita, K. Masuda, T. Matsubara, O. Matsubayashi, K. Mizoguchi, N. Nakamura, K. Otsuki, T. Shimamoto, H. Sone, M. Takahashi |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1815-381X
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Digitales Dokument |
URL |
Erschienen |
In: eEarth ; 3, no. 1 ; Nr. 3, no. 1 (2008-02-29), S.1-6 |
Datensatznummer |
250000775
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Publikation (Nr.) |
copernicus.org/ee-3-1-2008.pdf |
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Zusammenfassung |
The iron content and the asymmetry of iron and magnesium ions in chlorites
are examined for the Chelungpu Fault in Taiwan, which is a seismogenic
fault. The samples are collected from the cores drilled for the Taiwan
Chelungpu Fault Drilling Project (TCDP, borehole B). Three fault zones are
recognized as candidates for the source of seismogenic materials. The fault
zones are composed of fractured-damaged rocks, breccia, gray gouge, black
gouge, and black material. Chlorite from each type of rock was analyzed by
using X-ray diffraction (XRD). The iron content and asymmetry of the iron
and magnesium ions in the chlorites were estimated from the XRD peak ratios.
The hydroxide and silicate layers of chlorite in the black gouge and black
material have low iron contents. Many studies have suggested that a
temperature rise occurred at the fault zones. In addition, the temperature
rise can result in the production of iron oxides such as magnetite or
maghemite, as reported by other studies. However, the temperature rise
cannot explain the low value of iron content in the chlorites. Another
reason for the low value of iron content is the variation in the pH of the
fluid, which can be controlled by radical reactions. Therefore, on the basis
of chlorite characteristics, the reactions at the seismogenic fault are due
not only to the thermal decomposition resulting from the temperature rise
and but also to rock-fluid interactions. |
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