著者

Ichiro SUNAGAWA Yasushi TAKAHASHI Hiroyuki IMAI

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.102, no.3, pp.174-181, 2007 (Released:2007-07-03)

参考文献数

20

被引用文献数

35 39

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Alternating layers of calcite and aragonite, precipitated from mineral spring in fracture zones of serpentine mass, occur at Kashio, Oosika mura, Nagano Prefecture, Japan. Element mapping by means of Micro-area X-ray Fluorescence (MXRF) conclusively demonstrated that strontium concentrates more in aragonite layer, and not in calcite layer. Other elements including magnesium show no positive correlation with aragonite precipitation. MXRF analyses of aragonite samples from other localities and origins also indicated concentration of Sr as major impurity component, demonstrating that Sr plays essential role in metastable nucleation of aragonite in the precipitation of CaCO3 polymorphs from aqueous solution. This can be understood on the basis of modifications of surface energy term in CaCO3 nucleation in the presence of Sr. Temperature changes trigger to increase the Sr concentration in mineral spring, leading to metastable nucleation of aragonite.

著者

今井 博之 Hiroyuki IMAI

出版者

国立社会保障・人口問題研究所

雑誌

人口問題研究 = Journal of Population Problems (ISSN:03872793)

巻号頁・発行日

vol.78, no.1, pp.200-203, 2022-03

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資料

著者

Satoshi MATSUBARA Ritsuro MIYAWAKI Kazumi YOKOYAMA Masaaki SHIMIZU Hiroyuki IMAI

出版者

一般社団法人日本鉱物科学会

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

vol.99, no.6, pp.363-367, 2004 (Released:2005-01-07)

参考文献数

19

被引用文献数

3 9

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Tokyoite, Ba2Mn3+(VO4)2(OH), the Mn3+-analogue of gamagarite, is found from the Shiromaru mine, Okutama, Tokyo, Japan. It is monoclinic, P21/m, a = 9.10(4), b = 6.13(2), c = 7.89(5) Å, β = 112.2(5)°, Z = 2. The strongest lines in the powder X-ray diffraction pattern are 3.73 (15) (111), 3.31 (100) (112), 3.08 (20) (020), 3.00 (16) (301, 212, 102), 2.90 (19) (120), 2.80 (62) (121, 300), 2.16 (18) (321), 1.963 (15) (204). Electron microprobe analysis gave V2O5 31.77, SiO2 0.15, Al2O3 0.07, Fe2O3 2.33, Mn2O3 11.27, CaO 0.07, BaO 51.91, SrO 0.22, Na2O 0.13, H2O (calc.) 1.59, total 99.51 wt. %, and lead to the empirical formula, (Ba1.92Na0.02Sr0.01Ca0.01)Σ1.96(Mn3+0.81Fe3+0.17Al0.01)Σ0.99[(V1.99Si0.01)O7.92](OH)1.00 on the basis of V + Si = 2 and (OH) = 1. It is translucent and black red in color with a vitreous luster. The streak is dark brownish red and cleavage is not observed. The Mohs' hardness is about 4 to 4.5. The calculated density is 4.62 g/cm3. It has distinct pleochroism, from reddish orange to dark brownish red in thin section and the calculated mean refractive index is 2.03. It occurs as irregular grains under 15 μm, and the aggregates are up to 250 μm wide in association with braunite, hyalophane and tamaite. The mineral is formed under the later stage activity of low grade metamorphism.