title: [Characteristics of Raman spectra of natural clinochlore at 200 degrees C and 0.95-7.70 GPa].
abstract: Variation of crystal structure of natural clinochlore with pressure was investigated by the approach of diamond anvil cell (DAC) and in situ micro-Raman spectroscopic measurement at 200 degrees C and up to 7.7 GPa. The 481 and 786 cm(-1) peaks shift towards high-frequency linearly with increasing pressure at 200 degrees C. The linear relations between Raman shift (N, cm(-1)) and pressure (P, GPa) for the two peaks are: N = 11.136P+482.6 (R2 = 0.987 4) and N = 5.055P+785.7 (R2 = 0.983 7), respectively. The 865 cm(-1) peak arising from the stretching mode of the Si-O(nb) shifts slightly because of the strong repulsion between T cations at the tetrahedral sites and M cations at the octahedral sites in the TOT layer. Raman shift of 481 cm(-1) and 786 means the shortening of the length of M-O(br) and Si-CO(br) bonds since the peaks are contributed by the stretching mode of the M-O(br) and Si-O(br) respectively. No phase transition of clinochlore under the experimental condition was found. The results indicate that chlorite minerals may be stable at least at a depth of 80-90 km in the cold subduction zones, and the fluid derived from chlorite dehydration may be an important fact for earthquake occurrence in the subduction zones.
authors.affiliation: Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China. chao.xie0017@163.com
authors.forename: Chao
authors.initials: C
authors.lastname: Xie
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Du
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Yue-Ju
authors.initials: YJ
authors.lastname: Cui
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Li