Quarter ESR Signals Detected from Natural Clay Minerals and Their Applicability to Radiation Dosimetry and Dating

概要

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Some ESR signals have been detected from fault clay gouge of the Nojima Fault exposed by the Hyogo-ken Nanbu Earthquake in 1995. One signel may be attributed to a hydroxil radical (HOHC; Si-O°H) binding with a H_2O^+ ion which is obtained by ionizing interlayer water in montmorillonite (Si-O°H_3O^+). The oxygen hole center (OHC; SiO°) combining with a hydronium ion (H_3O^+) is split into quarter lines with the intensity ratio of 1:3:3:1 by hyperfine coupling of three equal protons (I=1/2). The quartet signal had often been detected from hydrothermal silicas or weathered feldspars in nature, however its physical model has not yet been established. Another signal is attribute to a CO^<3->_3 radical stabilized by an exchangeable cation existing in the interlayer and detected only by artifical irradiation due to its low thermal stability. These ESR signals uniformly increase upon artificial irradiation with X-rays and are applicable to radiation dosimetry (0.1-20kGy) and dating (0.01-20 Ma).
社団法人応用物理学会の論文
1996-03-15