| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
Fine-grained sediments of the Kwanmon Group(Cretaceous)had been studied mineralogically and chemically.
Mineral Composition : Fine-grained sediments are constituted by detrital grains, fine matrix, and cementing materials. The-detrital grain is mainly composed of quartz, feldspars, rhyo-dacitic and andesitic volcanic rocks, and red shale. The matrix is composed of illite, illite/smetite, " chlorite", hematite, goethite and pyrite. Illite-illite/smectite is very common without respect to stratigraphic horizon or rock-type. It is characteristic that the sediments are largely cemented by such carbonate minerals as calcite, dolomite, siderite, and rarely quartz.
Chemical Composition : The Cretaceous sediments have a wide range in chemical composition than basement sediments(Jurassic). The frequency(%)distribution patterns of SiO_2/Al_2O_3 are very similar to those of volcaniclastic sediments, which suggests that the sediments may partly contain volcaniclastic materials. The Fe_2O_3/Al_2O_3 ratios of them, especially pf purple shale, often exceed those of basalt. The frequency(%)distribution patterns of MnO/Al_2O_3, MgO/AL_2O_3 and CaO/Al_2O_3 are very similar to each other. The ratios are discreted into very low and high, which suggests that these elements may have moved in sediments after deposition. The TiO_2 and K_2O ratios to Al_2O_3 are fairly constant without respect to stratigraphic horizon and rock-type.
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