著者

池田 則生 肥田 博行 野口 一明 藤原 操

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.33, no.178, pp.97-114, 1982-05-10 (Released:2009-12-14)

参考文献数

34

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The tungsten-copper-tin deposit of the Takatori mine is of plutonic vein type and developed in alternating beds of sandstone and shale which constitute Yamizo Group of Triassic age. Detailed examination on the mode of occurrence of the deposit both in the underground and in the field has provided some important informations and suggestions for future exploration. Our observations and conclusions in this study may be sum-marized as follows:(1) Vein fractures in the deposit are classified into two groups, i.e., "Tatehi" group and "Yokohi" group. Fractures of the former in general trend NWW-SEE and steeply dip southward, while those of the latter are almost horizontal but in general gently dip northward. The two groups of fractures constitute a set of conjugate shears under the same stress field, principal stress axes of which being as follows; maximum compressional stress axis (σ1): S25°W30°, intermediate compressional stress axis (σ2): trending NWW-SEE and nearly horizontal, and minimum compressional stress axis (σ3): N30°E60° with angle of shear planes (2θ) of 80°.(2) Three mineralization stages are identified, i.e., wolframite-quartz stage, sulfide-quartz and cassiterite-quartz stage, and barren quartz stage with only pyrite, in chronological order.(3) At Nanabanhi Vein, the champion vein of the deposit, a vertical metal zoning is clearly observed, i.e., wolframite-rich zone, chalcopyrite-rich zone and cassiterite-rich zone in ascending order.(4) The localization of ore shoot appears to be structurally controled by some faults named as No.7 fault, No. 15 fault and W28 fault at-7 level, among which No.15 fault, being located in the central part of the deposit, is assumed to have acted as a channel feeder of ore fluid. All the faults were formed prior to the mineralizations and were probably in active during a certain period after the mineralizations as well.(5) It is suggested that the vein fracture systems were related in origin to the intrusion of a granitic magma. Namely, the uplifting of the southern geologic block with northwestward tilting at the stress field given by the granitic intrusion is considered to have been responsible for the reverse S-shaped regional structure of the area to have resulted the vein fracture systems observed.

著者

鹿園 直建 原田 広康 池田 則生 柏木 洋彦

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.38, no.5, pp.149-160, 2009 (Released:2009-11-26)

参考文献数

20

被引用文献数

3 3

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Dissolution kinetics model calculations were performed for the interaction between three types of basaltic rocks in Japan (Fuji and Hachijyojima fresh basalts and Kitamatsuura altered basalt) and groundwater injected CO2. Dissolution rates of the basalts experimentally determined by the authors (Shikazono et al., 2008) and database of dissolution rate constants of silicate minerals in the basaltic rocks in PATHARC (Talman et al., 2000) were used for the calculations. The results of calculations indicate that most of dissolved carbon in groundwater injected CO2 can be fixed as carbonates in long-term period. The efficiency of carbon fixation is in an order, Hachijyojima>Fuji>Kitamatsuura. But the efficiency is not so different for three basaltic rocks in the fixation of carbon in underground sequestration of CO2. It is inferred that mineral trapping of CO2 by carbonates in basalt aquifer is useful for the long-term fixation of carbon in underground sequestration of CO2.