The differencies in modes of occurrence and mineralogical habites for mica clay minerals constituting clay veins in the Hiroshima and the San'in granitic complexes have been examined by X-ray powder diffraction, DTA, electron microscopic observation and pH method. Mica clay minerals in the Hiroshima granitic complexes: The clay veins consist of mica clay minerals with an accessories of kaolin minerals and montmorillonite. The mica clay mineral was identified to be 1 Md polytype and were poorly crystallized crystal. The Al/Fe+Mg ratios in octahedral positions of the mica minerals is lower than that of the ones from the San'in granitic complexes. Most DTA curves show double endothermic peaks reduced to the main dehydroxylation : one of the peaks appears at about 500°C and the other is between 650-700°C. Those crystals consist of thin irregular plate and elongated-tabular. The abrasion pH value suggests that the minerals was formed under acidic condition. Mica clay minerals in the San'in granitic complexes: The clay veins consist of mica clay minerals with an accessories of chlorite, kaolin minerals and montmorillonite. Mica clay minerals are 2M₁, 1M and 1 Md polytypes and are well crystallized crystals. The Al/Fe+Mg ratios for most specimens are higher than that of the mica minerals from Hiroshima granitic complexes. The main dehydroxylation reaction of most specimens occurs between 650-700°C. Some hexagonal plates with irregular plates and elongated-tabular forms are observed. The abrasion pH values suggest that some of them were formed under the acidic conditions and the others the alkaline ones.

抄録全体を表示

Some of chlorite minerals in the Sanbagawa green shist have been converted to vermiculite-like mineral by weathering. Their mineralogical properties are clearly different from those of normal chlorite and vermiculite. The 001/002 intensity ratio of the minerals increases with the increase of weathering from 0.4 to 1.2. Normal chlorite found in the shist gives the ratio between 0.2 and 0.4, and vermiculite shows the ratio above 2.5. It is not sure that the minerals are interstratified chlorite and vermiculite, but they always occur with interstratified mica and expandable layer derived from sericite in the shist.

抄録全体を表示

Coarse-grained chlorite (penninite) flakes in talc-chlorite vein, which developed in serpentinite body at Torika, Saipi-cho, Nagasaki Prefecture, were investigated by X-ray, chemical and thermal methods, and it was clarified that a part of chlorite flakes are altered into a regularly interstratified chlorite/vermiculite by weathering. The regularly interstified chlorite/vermiculite gives hkl reflections, which have been indexed in terms of an orthohexagonal cell (a=5.34, b=9.25, c=28.8 Å). A stacking sequence composed of I vermiculite and IIb chlorite layer types was found on the basis of the 20 l intensities.

抄録全体を表示

Mixed-layer kaoline-montmorillonite are found in the weathering zone of acid clay deposits from Itoigawa, central Japan. A small amount of gibbsite and goethite occurs with them. The spacing of the basal reflection of the mixed-layer contracts after heating at 100°, suggesting the kaoline layer in the interstratification to be halloysite. X-ray diffractograms of oriented specimens after heating at 400° for 1 hour indicate that the proportion of kaoline layer is estimated to be about 0.8 in the uppermost part unconformably overlaid by higher terrace deposit and decreases toward the lower part. In the acid clay overlaid by lower terrace deposit, mixed-layer kaoline-montmorillonite are scarecely found. This fact suggests that the production of the mixed-layer minerals proceeded with alteration of montmorillonite before the formation of lower terrace. High resolution electron micrographs show that fringes curve, diverge and change laterally in layer spacing. Such irregular stacking seems to be responsible for the weak and broad basal reflections in x-ray diffraction.

抄録全体を表示

The hydrothermal formation of regularly interstratified mica-montmorillonite and chlorite-montmorillonite was discussed with the following subject; (1) formation of montmorillonite as a preceding phase of regularly interstratified minerals, (2) change from irregular interstratfication to regular one, and (3) influences of kinds of interlayered cations on the formations of interstratified minerals.

抄録全体を表示

Typical montmorillonites from Cheto and Wyoming both in USA, and weathered montmorillonites from Nakajo in Japan : Hl (abnormal montmorillonite) and H4 (halloysite/montmorillonite mixed-layer) were analysed chemically, and structural formulas were calculated on the basis of positive charges of 44 per montmorillonite unit layer. Wyoming montmorillonite has more beidellitic components than Cheto one. Meanwhile, it is concluded that Hl is composed of 85 per cent Cheto-type montmorillonite layer and 15 per cent kaolin layer, and H4 is composed of 40 per cent Cheto-type montmorillonite layer and 60 per cent kaolin layer. The occurence, exchange cations and types of montmorillonite of major montmorillonite deposits of Japan are discussed. The temperatures for the waters and gases which contributed to the formation of the montmorillonites from volcanic ash and tuffs are also discussed.

抄録全体を表示

　黒鉱変質帯に産するmontmorilloniteの層間を,Ca,Mg,NaおよびKの各陽イオン均一にし,そのX線底面反射を相対湿度0～100%で測定した。その結果,それぞれのイオンに対する底面反射の挙動が明らかになった。　その中で特にNaとCaの場合の差が著しい相対湿度(r.h.40%)を選び,天然のNaとCaイオンを多く含むmontmorilloniteのX線回折図を検討した。混合層構造のmodelによる計算結果と比較すると,層間のNaとCaイオンはsegregationをしていると考えられる。

抄録全体を表示

Montmorillonites from the Nakajo acid clay deposit were investigated by X-ray diffreaction, chemical analysis and cation exchange methods. Predominant exchange cations in the specimens from the upper horizons of the deposit are Mg and Ca ions, while that in the specimens from the lower horizons is Na ion. Cation exchange reactions of montmorillonites in solutions having the same ion ratios as those of sea water were carried out. Properties of the solution containing exchange cations and ionic population in tetrahedral and octahedral layers are discussed.

抄録全体を表示

There are many hypotheses on the formation mechanism of mixed-layer minerals. In this paper, a formation mechanism of rectorite-type mixed-layer mineral from mica was investigated on the basis of experimental results. Dehydroxylated sericites were transformed into a mica/montmorillonite mixed-layer mineral by various leaching methods with acid solutions, molten LiNO₃, sodium tetraphenylboron, sodium cobaltinitrite, and solutions containing salts. By the above procedures, 2M type scricites were easily changed into a regularly interstratified mineral of mica/montmorillonite. A random mixed-layer mineral of mica/montmorillonite was formed from 1M sericite. In order to change the 2M sericitesinto a regularly interstratified mineral, they should be heated up to the temperatur range of dehydroxylation. The formation of a rectorite-type mixedlayer mineral from 2M sericite may be explained on the orientations of the (OH) bonds after release of the potassium ions.

抄録全体を表示

An ANOVA (analysis of variance) method was applied for the estimation of the factorial effects on the transformation from dioctahedral mica to mica/smectite interstratified mineral. Two kinds of characteristic variables, the transformationratio and the profile broadness (crystallite size), were obtained from two different X-ray profile analyses. one of which was from the resolved individual profiles and the other from the unresolved ones. Both analytic results were in good agreement. However, the ANOVA for principal components of the unresolved profiles was more informative than for the characteristic variables of the resolved ones. The following results were noticeable; (1) the transformation ratio was largely affectedwith the specimen preheating temperature and the stirring of solution, (2) the line profile of the starting specimen narrowed its broadness with the increase of the transformation ratio, which was remarkably responsible for the stirring effect. Some transformation mechanisms between them were discussed.

抄録全体を表示

　モンモリロナイトおよび水酸化アルミニウムーモンモリロナイト複合体の熱水処理によってカオリンーモンモリロナイト混合層鉱物を得ることができ,この混合層鉱物を検討の結果次のことが明らかとなった。 1.　同鉱物はカオリンーモンモリロナイト-脱水モンモリロナイトの3成分系の混合層構造であると考えられる。 2.　積層方式はランダム型である。 3.　合成条件の差によって構成層の比が異なった鉱物ができる。 4.　同鉱物の化学組成は,出発物質の組成とカオリナイトのそれの中間的な性格を持つ。　なお酸性白土鉱床の風化帯に産出するカオリンーモンモリロナイト混合層鉱物の諸性質も解明されつつあるので,これらが明らかにされた段階で,改めて生成過などに関する議論を行う予定である。

抄録全体を表示

The ionic compositions of zeolites and clays with relatively wide range of cationic substitution such as clinoptilolite, mordenite, stilbite, chabazite, montmorillonite, vermiculite and so on are expected to be used as one of the indicators of the physicochemical conditions under which these minerals have been placed. Brief discussions are given about the derivation of such geochemical informations as temperature and chemical composition of interstitial solution from the ion exchange isotherms of clinoptilolite, mordenite and montmorillonite in aqueous solution.

抄録全体を表示

In order to investigate the genesis of stevensite and “hydrated talc” experimentally, naturally occurring pectolite was treated hydrothermally with 1, 2 and 4 normal magnesium chloride solution and with basic magnesium carbonate for various Mg (in basic magnesium carbonate)/Si (in pectolite) molecular ratios ranging from 0.1 to 1.5. The products were examined by means of X-ray diffraction, thermal analysis, transmission and scanning electron microscopy and chemical analysis. As a result, it was found that pectolite alters to stevensite (Mg/Si=0.1-0.3), stevensite and serpentine (Mg/Si=0.5-1.0) and serpentine (Mg/Si=1.5) by hydrothermal treatment with basic magnesium carbonate treatment. On the other hand, it altered to “hydrated talc” and small amount of serpentine by magnesium chloride solution treatment, as reported previously (Sakamoto et al, 1975a). Some considerations were made on the mechanism of the conversion process of pectolite to these layer silicate minerals.

抄録全体を表示

The intensities of X-ray basal reflections of dioctahedral mica clay minerals were calculated on the basis of the mica compositions ranging from K₂ (Al, Si)₈ Al₄O₂₀(OH)₄ to (K, H₂O)_2-0 (Al, Si)₈ (Al₂Fe₂) O₂₀ (OH)₄. The triangular diagrams with three components, I(10Å)-I(5Å)-I(3.3Å) and I(5Å)-I(3.3Å)-I(2.5Å), were made from these intensities calculated. Figures showing relationship between I(10Å)/I(5Å) or I(10Å)/I(3.3Å) and the contents of interlayer or octahedral cations were also made. Basal reflection intensities were examined for some illite samples having different chemical compositions. These samples were plotted in the above-mentioned diagrams and figures. Relationship between the points of samples in the figures and their compositions were investigated. Some problems were pointed out for the practical method obtaining chemical compositions of dioctahedral mica clay minerals from the ratios of basal reflection intensities.

抄録全体を表示

X-ray basal reflections of ammonium-bearing mica clay minerals found in the Tobe pottery stones of Ehime Prefecture have been examined in comparison with those of usual potassium mica clay minerals. Both the two mica clay minerals comprise mica and mica/montmorillonite interstratified minerals. The minerals with ammonium are characterized by larger basal reflection spacings and stronger first basal reflections than those of potassium mica minerals, which can be attributed to the interlayering of ammonium ions in place of potassium ions. The differences in basal reflections between the two mica clay minerals are well represented in I (10 Å)-I (5 Å)-I (3.3 Å) and W₁-W₂ (peak widths of about 10 Å and 5 Å reflections) diagrams.

抄録全体を表示