著者

柚原 雅樹 鮎沢 潤 大平 寛人 西 奈保子 田口 幸洋 加々美 寛雄

出版者

日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.34, no.6, pp.275-287, 2005-11-30

被引用文献数

3 5

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The Cretaceous granitic rocks, the Kitazaki Tonalite and Shikanoshima Granodiorite, and veneer Oligocene sedimentary rocks, the Tsuyazaki Formation, are distributed in the Watari Peninsula, Fukuoka Prefecture. There are mineral veins composed by calcite and zeolites in those rocks. Rb-Sr, and fission track geochronological analyses were carried out for granitic rocks, in order to determine the cooling process of granitic rocks and timing of hydrothermal activity. Biotite and felsic fraction separated from the Kitazaki Tonalite and Shikanoshima Granodiorite give Rb-Sr isochron age of 108.6 ± 2.5 Ma and 107.0 ± 0.7 Ma, respectively. Fission track ages from the Kitazaki Tonalite are 97 Ma (titanite), 89-88 Ma (zircon), 14 Ma (apatite). Fission track ages from the Shikanoshima Granodiorite are 95 Ma (titanite), 87-84 Ma (zircon), 15 Ma (apatite). Fission track ages of apatite from granitic rocks are younger than the Tsuyazaki Formation, which suggests a thermal event at about 15 Ma to reset the fission track apatite age. The homogenization temperature of fluid inclusions in calcite are 89-111 °C (Kitazaki Tonalite), 95-118 °C (Shikanoshima Granodiorite) and 85-91 °C (Tsuyazaki Formation). Sr isotopic compositions of calcite and zeolites in granitic rocks and Tsuyazaki Formation are overlap with one another. These data suggest that vein minerals in granitic rocks and zeolites and calcite in the IC Member of the Tsuyazaki Formation were formed by a series of hydrothermal activity at about 15 Ma.

著者

田口 幸洋 広渡 文利 吉川 謙造

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.26, no.138, pp.263-271, 1976-10-30 (Released:2009-12-14)

参考文献数

15

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The Fuke mine, situated at about 10 km north of Okuchi city in Kagoshima Prefecture, is one of the gold-silver ore deposits of the epithermal vein type in the Green-tuff region. The ore deposit is considered to be an intermediate type between the gold-silver vein and the base metal vein.The high grade ore in the mine is named "Tozi-kin" in which can be visually recognized the part where fine-grained golds are concentrated. As for the electrum in this ore, mode of occurrence and chemical composition have been investigated by a microscope and EPMA. The results are as follows : 1. The Tozi-kin ore often shows a characteristic banded arrangement from the wall rock to the inner of the ore; Fe-Mg chlorite, drusy quartz with pyrite and hematite, fine-grained quartz with banded sulfides and electrum, and green clay mainly composed of chlorite-saponite mixed-layer.2. Paragenetic sequence of vein minerals may be divided into four stages; First stage: Drusy quartz accompanied by pyrite and hematite. Second stage: Fine-grained quartz characterized by sulfides and electrum. Third stage: Altered minerals. Fourth stage: Barren quartz associated with calcite. 3. Observed ore minerals are electrum, galena, sphalerite, chalcopyrite, pyrite, hematite, hessite, and an unkown Ag-Au telluride.4. Electrum precipitated after the precipitation of sulfides in the second stage.5. The electrum filling intergranular cavities of quartz is irregular and angular in shape, whereas that in sulfides varies from granular to cylindrical, and often amoebic.6. The grain size of electrum is generally less than 50 microns in diameter, but it attains 200 microns in some cases.7. The chemical composition of electrum from the Fuke-honpi vein shows a very little fluctuation among grains as well as in a grain, with an average chemical composition Ag 19.1 wt.%, Au 80.6 wt.%.Some of these properties of electrum such as the homogenity of composition and the relatively coarse grains, are considerably different from those of electrum in the Kuroko ore.

著者

RIOGILANG Hendra 糸井 龍一 田口 幸洋

出版者

日本地熱学会

雑誌

日本地熱学会誌 (ISSN:03886735)

巻号頁・発行日

vol.34, no.3, pp.151-159, 2012

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コタモバグ地熱地域の東西30 km,南北20 km において温泉水および関連した水の地化学調査を実施した。温泉水,河川水からなる31 試料を標高173 m から1438 m の間で採取し,化学成分および水の安定同位体比を測定した。同時に雨水を標高556 m から1500 m の間の5 地点で,2010 年3 月から6月にかけて採取した。ほとんどの温泉水は中性のHCO₃ 型および複合型であり,水の安定同位対比のグローバルな天水線上に分布し,天水起源であることを示唆している。しかし,酸性の水はこの天水線からずれている。Muayat 山の山頂付近の噴気地帯近傍で採取された試料(MUAH-16)はSO₄ タイプであり,蒸気加熱型であることを示唆している。酸性水試料が安定同位体の天水線からずれている原因は地表あるいは浅層での天水の蒸発と考えられる。中性でかつ本地域の天水線のδ^18Oからずれている試料LOBH-10 は本地域の周辺部に位置し,このずれは海生起源の岩石との反応が原因と考えられる。