[S-MP47_1PO1] Physics and Chemistry of Minerals

[SMP47-P08] The low-temperature Moessbauer spectroscopy of an M3' epidote from Osayama, Okayama prefecture, Japan

*Junji YAMAKAWA¹, Masaya KAWASE², Masayuki KUROKUZU³, Shotaro MORIMOTO⁴, Tadashi SAITO⁵ (1.Graduate School of Natural Science and Technology, Okayama University, 2.Nagahama Institute of Bio-Science and Technology, 3.Research Reactor Institute, Kyoto University, 4.Faculty of Pharmacy, Osaka Ohtani University, 5.Radioisotope Center, Osaka University)

Keywords:Epidote, Moessbauer spectroscopy, M3' site, Magnetic susceptibility

Epidote, Ca_2(Al,Fe³⁺,Fe²⁺)Al₂SiO₄Si₂O₇(O,OH) is a common rock forming mineral found low-grade metamorphic rocks. The chemical compositions of the epidote vary with the formation conditions and make some complex zoning textures. The distribution of Fe²⁺-Fe³⁺ ions in the crystal structure will be able to analyze by the Möossbauer spectrometry and the stability/unstability of the sample can be estimated from the distribution.Moreover, in some sample, the Fe ions are distributed in the characteristic M3^' site that can be detected by the Möessbauer spectroscopy. The distribution ratio of the Fe ions in the M3^' site can not be estimated by the X-ray structure analysis, so the M3^' sites are making a small ordering structures and distribute homogeneously in the crystal. Distribution ratio of Fe in the site of M1/M3/M3^' corresponds to the formation conditions of the sample.In this study, the low-temperature Möessbauer spectrum and Magnetic susceptibility of the M3^' epidote sample was measured and the characteristics of the M3^' site were analysed.