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敏彦 松田

Bio: 敏彦 松田 is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

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Journal ArticleDOI
TL;DR: In this article, the gold decoration technique of electron microscopy was used to observe the microtopography of natural (001) surfaces of 1:1 regularly-interstratified mica/smectite minerals (expandable layer: 40-45%).
Abstract: The gold decoration technique of electron microscopy was used to observe the microtopography of natural (001) surfaces of 1:1 regularly-interstratified mica/smectite minerals (expandable layer: 40–45%) collected from four different pyrophyllite deposits in Japan. The specimens are characterized by parallel growth steps of malformed, circular or polygonal forms with varying step separations. Many particles exhibit paired steps that seem to show spiral growth. Microtopographic observations suggest that the growth of regular interstratification (at least for the specimens investigated in this study) normally takes place by an interlacing of paired steps. If the height of a single step corresponds to that of a mica or a smectite layer, the particles are estimated to be normally 40–300 A in thickness. If the particles on which a spiral center is observed are single crystals of interstratified mica and smectite, then some crystals investigated in this study are far thicker than fundamental particles. The results of this study are interpreted to suggest that these regularly-interstratified mica/smectites were formed by hydrothermal metasomatism from their respective host rocks.

11 citations

Journal ArticleDOI
TL;DR: In this paper, a variety of techniques including microprobe analysis, infrared spectroscopy, single crystal and powder X-ray diffraction, atomic force microscopy and thermal analysis were used to study the mica-smectite interstratification.
Abstract: Rectorite crystals [ [4] (Si 6.81 Al 1.19 ) [6] (Al 3.26 Ti 0.04 Fe 0.55 3+ Mg 0.18 Mn 0.01 ) [12] (Na 0.02 K 0.88 Mg 0.16 Ca 0.01 )O 20 (OH) 4 ·0.75H 2 O] found in micaschist of the Sesia-Lanzo Zone (NW Italy) were studied using a variety of techniques including microprobe analysis, infrared spectroscopy, single crystal and powder X-ray diffraction, atomic force microscopy and thermal analysis. Chemical data and exchangeable cation determination indicate that K + is the dominant non-exchangeable interlayer cation, and thus is believed to occupy the mica interlayer site; Mg 2+ together with small amounts of Ca 2+ , Na + and K + represent the exchangeable cations and can therefore be related to the smectite-like component. The coefficient of variation, CV, of d (00 l ) values (CV natural = 0.47; CV glycolated = 0.43) demonstrates the regularity of the mica-smectite interstratification, whereas the unit-cell parameters obtained by single crystal methods suggest different layer-stacking models.

10 citations

Journal ArticleDOI
TL;DR: The most Ca-rich rectorite reported to date is Ca-rectorite from the Sano Mine, Nagano Prefecture, Japan as mentioned in this paper, which has a structural formula of (Mg0.16)EX(Ca0.59Na0.27K0.17[Al3.17]Al0.94Mg 0.08 Feo0.07Ti0.4]
Abstract: Rectorites containing various amounts of Ca were found at the Sano Mine, Nagano Prefecture, Japan. The Ca content in nonexchangeable form varied from 1.0 to 3.9% CaO. With more than 3.4%, they may be called Ca-rectorite. Chemical data of the most Ca-rich sample showed that Ca was the dominant interlayer cation, and gave a structural formula of (Mg0.16)EX(Ca0.59Na0.27K0.17[Al3.94Mg0.08 Feo0.07Ti0.01](Si5.85Al2.15)O20(OH)4. This sample is apparently the most Ca-rich rectorite reported to date. The Greene-Kelly test and an intercalation examination by octadecylammonium indicated that the expandable component layers were beidellitic. Assuming the tetrahedral composition of the expandable component layers are similar to the average tetrahedral composition of beidellite of (Si36Al0.4), the tetrahedral composition of the mica-like component layers was calculated to be (Si2.25Al1.75). This was closer to a brittle mica (margarite) than to a true mica. Examination of chemical data for several Ca-rectorite samples from different localities, including those from the Sano Mine, showed a trend of increasing Ca content as Al increased and Si decreased. Ca-rectorite exhibited characteristic infrared absorption bands at 480, 670–700 and 900–930 cm−1, which became more intense as Ca content increased. These bands also corresponded to major absorption bands of margarite.

5 citations

Journal ArticleDOI
TL;DR: In this article, the rehydration and rehydroxylation properties of homoionic rectorites (saturated with Ca 2+, Mg 2 § Na § or K +) were further investigated.
Abstract: The rehydration and rehydroxylation properties of homoionic rectorites (saturated with Ca 2+, Mg 2§ Na § or K +) were further investigated. The rehydration properties of the rectorite were characterized as follows: (l) basal spacings of rehydrated materials after heating above 500~ changed to 22.5 A for H20-complexes, 26.85 A for ethylene glycol-complexes, and 27.65 A for giycerol-complexes; (2) rehy- drated Ca- and Mg-materials exhibited single layer hydrates at <50% RH, and rehydrated K-material showed double layer hydrates at 80% RH; (3) IR absorption spectra due to rehydrated H20 and OH exhibited the same or very close absorption intensities and frequencies to each other; (4) DTA-TGA curves of rehydrated materials indicated that the amount of rehydrated H20 approached about 4.2 wt. %, and about one-half of OH was rehydroxylated after heating at 800"C; and (5) interlayer cations of expandable layer components became non-exchangeable after heating above 500"C. These results suggest the following rehydration mechanism of rectorite: the interlayer cations migrate into the hexagonal holes of the SiO4 network by thermal dehydration. The cations migrated below 400~ easily return to the interlayer space and their original hydrated configurations have been recovered completely on rehydration. However, those migrated above 500"C are fixed to the hexagonal holes but water molecules are regained in the interlayer space. Consequently, electrostatic effects of interlayer cations on formation of water molecule layers are considerably reduced.

4 citations