Clay Science
Online ISSN : 2186-3555
Print ISSN : 0009-8574
ISSN-L : 0009-8574
16 巻, 3 号
選択された号の論文の12件中1~12を表示しています
  • 原稿種別: 表紙
    2012 年 16 巻 3 号 p. Cover1-
    発行日: 2012年
    公開日: 2017/06/22
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  • 原稿種別: 付録等
    2012 年 16 巻 3 号 p. App1-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • 原稿種別: 付録等
    2012 年 16 巻 3 号 p. App2-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • 原稿種別: 付録等
    2012 年 16 巻 3 号 p. App3-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • 原稿種別: 付録等
    2012 年 16 巻 3 号 p. App4-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • ATSUYUKI INOUE, KYOHEI KUROKAWA, MIYUKI NITTA
    原稿種別: 本文
    2012 年 16 巻 3 号 p. 59-81
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
    In the paper, we synthesize current data on the hydrothermal alteration, microthermometry, and stable isotopic compositions together with published data on K-Ar ages and hydrology in order to understand the environment of mineral-fluid interaction conductive to metallic ore deposit in the Toyoha hydrothermal system. On the basis of our mineralogical data and published K-Ar dating data, hydrothermal alteration prevailed in the Toyoha system can be divided into at least three different stages: I, II, and III. The alteration of stage I, which took place before 12 Ma in connection with granitic activities, is characterized by pervasive propylitic alteration consisting of four hydrothermal alteration zones: biotite, epidote-actinolite, illite-chlorite, and corrensite zones with decreasing temperature. The zonal arrangement is nearly parallel to the stratigraphic boundaries in the Toyoha area, though it was modified by later geologic events to some extent. The alteration of stage II is also of propylitic in nature as a whole, but it accompanied the formation of specific minerals such as allanite and tourmaline along with K-feldspar, relatively Fe-rich chlorite, and 2M_1 illite. Insignificant ore deposition of base metals was locally associated with hydrothermal activity of this stage. The occurrence of the above specific minerals was close to granitic intrusion which took place at about 10 Ma, suggesting that there was significant contribution of magmatic components in fluids responsible for the alteration, compared to the propylitization at stage I. The alteration of stage III took place for the last 3 my and brought on the ore deposition in Toyoha veins and the adjacent district. The ore mineralized zone was enveloped by the kaolin minerals zone and in turn the mixed-layer minerals zone toward the upper surface. Remarkable silicification occurred upon the surface along the Yunosawa fault. The development of hydrothermal alteration zones together with the ore deposition at Toyoha resulted from large-scale hydrothermal fluid circulation. The ancient temperature distribution during the alteration of two stages I and II was estimated using the chlorite geothermometry, along with the distribution of alteration minerals and microthermometric data. On the other hand, the environment of mineral-fluid interactions in the alteration of stage III was analyzed in more detail using fluid inclusion data, carbon and oxygen isotopic compositions of calcite and rhodochrosite, and geochemical calculations of fluid recovered from TH-6, in addition to the use of chlorite geothermometry. The ore deposition was caused by the mixing of ascending deep fluid and descending ground water. The chloride concentration of ascending deep fluid was probably lower in the eastern peripheral area, compared to those of fluids responsible for the formation of major ore veins. The conclusions obtained here, though they were actually derived from studies of drill cores adjacent to the Toyoha epithermal ore deposit, provide insight into understanding the environments conductive to metallic ore deposition at Toyoha.
  • NGUYEN THI HANG NGA, SHIN-ICHIRO WADA
    原稿種別: 本文
    2012 年 16 巻 3 号 p. 83-88
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
    To evaluate the relative flocculating power of allophane and imogolite, we conducted a series of flocculation experiment using allophane and imogolite sols and their mixtures. Imogolite was more effective than allophane for all five clay suspensions used. The residual turbidities of test montmorillonite suspensions after treatment with mixed allophane and imogolite sols were nearly equal to those calculated under the assumption that the contribution of allophane and imogolite was additive. But the experimental turbidity was much higher than the calculated one for a soil clay suspension.
  • TERUHISA HONGO, DAISUKE TAKASHIMA, SHOTA UMEHARA, SHIGEO SATOKAWA, AKI ...
    原稿種別: 本文
    2012 年 16 巻 3 号 p. 89-93
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
    Ceria-clay composite was prepared using a nonionic poly(ethylene oxide) surfactant. The preparative conditions with regard to the surfactant amount and calcination temperature were changed, to study their effects on the mesostructure of the ceria-clay composite. The specific surface area, pore diameter, and pore volume increased with increasing surfactant amount. The calcination temperature had little influence on the mesostructure up to 650℃, but the structure collapsed above 750℃. The crystallite size of ceria, estimated using the Scherrer's method, decreased with increasing surfactant amount, and increased with increasing calcination temperature above 750℃. The ceria-clay composite catalyzed the complete combustion of methanol at 300℃.
  • AFLAKHUR RIDLO, MASAMI OHTSUBO, TAKAHIRO HIGASHI, MOTOHEI KANAYAMA, MA ...
    原稿種別: 本文
    2012 年 16 巻 3 号 p. 95-104
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
    The mineralogical, chemical, and physical properties of Mexico City clay sediments from depths of 5 to 19 m are presented, and an attempt is made to specify the mineralogy and chemistry responsible for the unusually high liquid limit of the clay. An X-ray analysis of < 2 μm clay fractions indicated the presence of smectite, as a principal clay mineral, and amorphous material. The contents of poorly crystalline Si, Al, and Fe extracted with oxalate were found to be in the ranges of 32-57, 23-54, and 133-273 g/kg, respectively, and the ferrihydrite content was as high as 226-464 g/kg. The high observed pH of 9.1 to 10.1 was due to the presence of large amounts of carbonate. Pore water salinity ranged from 51 to 84 g/L and was 1.4 to 2.4 times higher than seawater salinity. Clay and silt were the dominant grain-size fractions, and the clay fraction (< 2 μm) varied from 19% to 51%. The specific surface area varied widely from 26 to 436 m^2/g. Because of the high pore water salinity, the original water contents of the clay needed to be modified by taking into account the weight of the salt present in the oven-dried samples. The modified natural water contents, liquid limits, and plastic limits were in the range of 42% to 641%, 45% to 798%, and 33% to 76%, respectively. The activity of Mexico City clay ranged from 5.6 to 13.9, which was much higher than that for reference samples of bentonite and smectitic marine clays. Despite smaller clay fractions in Mexico City clay than in bentonite, Mexico City clay exhibited liquid limits as high as 194% to 798%, which were equivalent to those of bentonite. This is attributed to the predominance of smectite, ferrihydrite, and amorphous Si and Al in the clay and also to the formation of aggregates due to the presence of ferrihydrite. A linear correlation was found between the liquid limit and specific surface area for the combined data of Mexico City clay, bentonite, and marine clay.
  • 原稿種別: 付録等
    2012 年 16 巻 3 号 p. App5-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • 原稿種別: 表紙
    2012 年 16 巻 3 号 p. Cover2-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
  • 原稿種別: 表紙
    2012 年 16 巻 3 号 p. Cover3-
    発行日: 2012年
    公開日: 2017/06/22
    ジャーナル フリー
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