粘土科学
Online ISSN : 2186-3563
Print ISSN : 0470-6455
ISSN-L : 0470-6455
28 巻, 2 号
選択された号の論文の4件中1~4を表示しています
  • 分析電顕による研究その1
    青木 三郎, 神山 宣彦
    1988 年 28 巻 2 号 p. 1-10
    発行日: 1988/06/10
    公開日: 2011/09/20
    ジャーナル フリー
    A piston core sample collected from off Boso Peninsula, Chiba Prefecture and a sample of late Oligocene calcareous mudstone collected from Daito Ridge have been examined for clay mineralogy by means of X-ray powder diffraction (XRD) and analytical transmission electron microscopy (ATEM). The<2 μm fractions of the subsamples from the piston core were composed principally of smectite, chlorite, illite and kaolinite. The smectite belonged to an iron-rich member, and the chlorite comprised iron-and iron-magnesium types. The proportion of smectite tended to decrease since the late Glacial period, while that of illite showed the opposite trend. The<2μm fractions from the calcareous mudstone was composed almost entirely of smectite low in iron content. The low iron content suggested that the smectite was of terrigenous origin sedimented during the late Oligocene.
  • 中川 昌治
    1988 年 28 巻 2 号 p. 11-29
    発行日: 1988/06/10
    公開日: 2011/09/20
    ジャーナル フリー
    The constituent minerals of the ores of the Amakusa pottery stone deposits have been examined by X-ray powder method, electron probe microanalysis, differential thermal analysis, polarizing microscopy, etc. The main constituent minerals of the pottery stones are quartz, sericites and kaolinite. Minor components of them are dickite, rectorite, tosudite, smectite, plagioclase, K-feldspar, calcite, siderite, pyrite, etc., among which the first three minerals occur only in the Sarayama vein. Feldspar, carbonate and pyrite are more abundant in the Kaigan and Murayama veins.
    X-ray diffraction peaks of the quartz are broard. The cell dimensions are relatively large with α=4.9137-4.9154 Å and c=5.4047-5.4057 Å at 21°C. Most quartz samples show relatively high Al2O3 contents around 0.1wt% up to 1wt% in maximum, and are inhomogeneous in the Al2O3 content among grains. The high-low inversion peak in the DTA curve is broad and the peak temperature is lower than that of common quartz.
    Sericites in the ores of the Sarayama vein comprises coarse-grained 2M1 and 1M micas and finegrained irregularly interstratified 1M mica/smectite with small amounts of smectite layers. Sericites in the ores of the Kaigan and Murayama veins are mostly coarse-grained 2M1 and 1M micas. These coarse-grained micas often form banded structure in which 2M1 mica tends to grow inside. Tetrahedral and interlayer compositions of the 2M1 mica are close to those of ideal muscovite although octahedral Fe and interlayer Na are appreciably contained. The 1M mica and fine-grained irregularly interstratified 1M mica/smectite have less tetrahedral Al and interlayer cations, and the contents of octahedral Fe and interlayer Na are very small. Such a difference in chemical composition between 2M1 and 1M micas is most pronounced in those of the Sarayama ores. The observed variations of sericites in chemical composition, polytype and interstratification are discussed with their genesis.
  • 大坪 政美, 和田 信一郎
    1988 年 28 巻 2 号 p. 30-37
    発行日: 1988/06/10
    公開日: 2011/09/20
    ジャーナル フリー
    The paste of kaolinite-amorhous iron hydroxide complexes initially prepared at pH3.0 and 9.5 were brought to equilibrium at different pH values of pH3-10. The electron micrographs showed that association between iron hydroxides and kaolinite particles in the complexes at a given pH value was affected by the initial pH of the complexes. Liquid and plastic limits for the paste of the complexes have been examined as a function of pH. The complexes prepared initially at pH3.0 and 9.5 both gave higher liquid and plastic limits than kaolinite in the whole pH range, and the amorphous iron hydroxide in the complexes prepared at pH9.5 were more effective in enhancing the liquid and plastic limits. The results are discussed in terms of the charge characterisics of the amorphous iron hydroxide and its association with kaolinite by means of electron microscopy and zeta potential determination.
  • そのトレーサーとしての意義
    溝田 智俊, 井上 克弘
    1988 年 28 巻 2 号 p. 38-54
    発行日: 1988/06/10
    公開日: 2011/09/20
    ジャーナル フリー
    Oxygen isotopic composition (δ18O notation, expressed as ‰ deviation relative to Standard Mean Ocean Water, SMOW) of quartz provides a direct evidence for provenance of soils and sediments in which quartz is an ubiquitous mineral constituent. The δ18O values can be used as a tracer in evaluation of eolian contribution. Principle of temperature-dependence of 18O/16 O fractionation between silica and water and procedures for isolation of monomineralic quartz from soils and sediments were outlined. Relevant data for the oxygen isotopic composition of eolian quartz from various parts of the world were compiled and discussed in relation to their geographic distribution. The oxygen isotopic composition of eolian quartz is in the intermediate values of high and low-temperature origins, the extent being dependent upon the proportion of each types of rocks in the source regions. Three distinctive provenances of the eolian dusts were established. The first group (δ18O=+19-+20‰) consists of those from mid-continental U. S. A. and desert regions of Afganistan and India, the second (δ18O=+16‰) from Sahara-Sahel and interior China, the third (δ18O=+13-15‰) from South Africa, Australia and New Zealand. The δ18O values (+18‰) from Hawaiian Islands are in between the first two gropus. Further systematic sampling and determination ofδ18O of quartz in desert materials from which eolian dust derives were emphasized.
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