JaLCDOI 10.18926/ESR/13934
FullText URL ESR_3_47.pdf
Author Matsuda, Toshihiko| Kurosaki, Makoto|
Abstract Several specimens of rectorite-type regularly interstratified mineral (including Ca-rich one of hydrother-mal origin) from roseki deposits together with a few rectorites were examined by chemical analysis, X-ray diffraction and IR spectroscopy. These specimens are rich in SiO2, AI2O3 and H2O in addition to considerable amounts of CaO, Na2O and K2O. The Ca content in mica-like layers ranges from a slight amount to exceeding 50% of the total interlayer population. For the Ca-bearing specimens, AI-for-Si substitution in the tetrahedral sheets of mica-like layers increases in proportion to the Ca contents. Characteristic absorption bands of 950-900 cm-1 and 700-670 cm-1 are observed in IR spectra. The bands are due to AI-for-Si substitution in the tetrahedral sheets. Judging from the chemical analysis and IR spectra, the component of mica-like layer rich in Ca is not that of mica but mainly that od margarite (brittle mica). Expansion characteristics of the Ca-rich mineral are similar to rectorite and expandable layer is close to beidellite. The mineral is somewhat less expandable than rectorite under the condition of RH70-80% (Na-saturation) and EG treatment (K-saturation). The rectorite-type Ca-rich mineral reported here is simlar to rectorite in its expansion characteristics, but the component of mica-like layers is different from that of rectorite. Mica-like layer of the mineral must be mainly composed of margarite-like layer. The mineral is mainly composed of a 1 : 1 regular interstratification of dioctahedral britlle mica (margarite) and smectite (beidellite). The mineral does not strictly correspond to rectorite, defined as a 1 : 1 interstratified mineral of dioctahedral mica and smectite.
Keywords rectorite brittle mica/smectite margarite regular interstrarification
Publication Title Okayama University Earth Science Report
Published Date 1996-09-20
Volume volume3
Issue issue1
Start Page 47
End Page 56
ISSN 1340-7414
language 英語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310640
JaLCDOI 10.18926/ESR/13933
Title Alternative Sulfur isotope ratios of some Roseki deposits in the Inner Zone of Southwest Japan
FullText URL ESR_3_43.pdf
Author Yamamoto, Masahiro| Matsuda, Toshihiko| Nakagawa, Raiki|
Abstract Sulfur isotope ratios of pyrite and alunite from 5 Roseki deposits in the Inner Zone of Southwest Japan were determined. The δ34S values of all pyrite samples were in the range from -13.2 to +2.3%, the variation range for each deposit being within 8%. In each deposit δ34S values of alunite were always higher than those of pyrite, which may be interpreted as that alunite was precipirated under more oxidizing conditions than pyrite. Sulfur isotope rations of the Roseki pyrite showed a distribution similar to that of ore sulfur from skarn and vein deposits in the same Zone. This suggests that the origin of sulfur of the Roseki deposits is also host igneous rocks.
Keywords sulfur isotope ratio Roseki deposit pyrite alunite
Publication Title Okayama University Earth Science Report
Published Date 1996-09-20
Volume volume3
Issue issue1
Start Page 43
End Page 46
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310309
JaLCDOI 10.18926/ESR/13888
Title Alternative Relationship between the water quality of three main rivers and geology of Okayama Prafecture
FullText URL ESR_8_1_29.pdf
Author Kinoshita, takuya| Matsuda, Toshihiko|
Abstract Concentrations of inorganic major components (Ca2+, Mg2+, Na+, K+, ΣFe, AI3+, HCO3, SO4, CI-, NO3, F- and SiO2) were measured in 57 water samples from three main rivers, the Yoshii, Asahi and Takahashi Rivers and their tributaries. The water quality is discussed in relation to the geological environment in the drainage basin of three rivers. The following results were obtained from the investigation. The degree of influence of rocks on the water quality was limestone≫basic rocks>clastic rocks>andesite>rhyolite>gramite. The influence of geology is clear in the riverhead but it is obscure in the downstream. The concentration of each component increases generally from the upper stream to the lower stream but that of SiO2 only decreases in the lower stream. Kaolinite is a stable mineral as a weathering prodouct from the ion compositions of three rivers. In a rough estimation, Yoshii, Asahi and Takahashi Rivers weather 303,000t, 433,000t and 1,033,000t of the rocks respectively from their basins in a year. The syrface of their basins are scraoed off 0.06mm, 0.11mm and 0.15mm respectively in a year.
Keywords Water quality River water Geology of basin Yoshii River Asahi River Takahashi River Okayama Prefecture
Publication Title Okayama University Earth Science Report
Published Date 2001-09-20
Volume volume8
Issue issue1
Start Page 29
End Page 38
ISSN 1340-7414
language 日本語
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310339