Statistical Features of Vein Systems in the Hishikari Epithermal Gold Deposit, Japan

Sasaki, Mitsuru

doi:10.1111/j.1751-3928.2006.tb00265.x

Cited by 13 publications

(9 citation statements)

References 23 publications

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“…Concrete containing plastics have been used in various projects and countries. (Sasaki, 2006) reported that PET fiber reinforced concrete was successfully used in the Hishikari mine (Gold Mine) located in Kagoshima, Japan. Evaluation of surfaces sprayed with PET fibers showed that the surfaces were relatively smooth with no cracking, uplifting or deviation.…”

Section: Various Field Applications Of Plastic Fiber Reinforced Concretementioning

confidence: 99%

Use of different forms of waste plastic in concrete – a review

Sharma

Bansal

2016

Journal of Cleaner Production

346

119

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Section: Various Field Applications Of Plastic Fiber Reinforced Concretementioning

confidence: 99%

Use of different forms of waste plastic in concrete – a review

Sharma

Bansal

2016

Journal of Cleaner Production

346

119

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“…Mineralized quartz veins in the Hishikari deposits generally strike N40–50°E and dip 70–90°N (Sasaki ). The strike length of each vein is 300–400 m, and vein width ranges from 0.4 to 4 m (maximum 13 m) (Ibaraki and Suzuki ; Sekine et al ; Sasaki ). The mineralized zones are mainly 100 to 300 m below the present surface (Ibaraki and Suzuki ; Sasaki ).…”

Section: Geological Backgroundmentioning

confidence: 99%

Characteristics and Behavior of Hydrothermal Fluids for Gold Mineralization at the Hishikari Deposits, Kyushu, Japan

et al. 2017

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The Hishikari gold–silver deposits in southern Kyushu, Japan, are low‐sulfidation vein‐type epithermal deposits. Bulk composition analysis, fluid inclusion microthermometry and quantitative gas composition analysis on the basis of the crush‐fast scan (CFS) method were conducted to elucidate characteristics and behavior of hydrothermal fluids responsible for the gold mineralization of the Hishikari deposits. Quartz vein samples were collected from widely scattered locations of ore veins: Zuisen‐6, ‐3, ‐1 (Main deposit), Keisen‐2 and Shosen‐5 (Sanjin deposit), and Seisen‐8 (Yamada deposit) between −70 and 64 ML (mine meter level). The samples are composed mainly of quartz and adularia, and ore minerals of electrum, pyrargyrite, pyrite and/or stibnite, having an average bulk Ag/Au weight ratio of 0.54. Fluid inclusions in quartz and adularia are two‐phase liquid–vapor, and their trapping temperatures and salinities are ca. 190–220 °C and 1.5–2.7 wt.% NaCl eq., respectively. The salinity is highest with an average 2.4 wt.% NaCl eq. of the fluid inclusions from the deepest level (Zuisen‐6 vein at −70 ML), while the fluid inclusion salinities from other samples are relatively low less than ca. 2.0 wt.% NaCl eq. Parallel‐ and lattice‐bladed quartz occur in a number of veins, suggesting fluid boiling during the vein formation. Gases of fluid inclusions are composed mainly of H2O (93.4–99.8 mol%) and CO2 (0.15–6.2 mol%), N2 (0.007–0.96 mol%), Ar (0.0001–0.0047 mol%), CH4 (0.002–0.048 mol%), H2S (0.0004–0.0028 mol%), H2 (0–0.074 mol%) and He (0.0002–0.0011 mol%). CO2, N2 and Ar contents of the fluid inclusions are elevated in the samples collected from deep levels, while H2O, H2S and He contents are elevated in those from shallow levels. The Ar/He, CO2/CH4 and N2/Ar ratios of fluid inclusion gas indicate a systematic transition from magmatic to meteoric signatures in order from deep to shallow levels. The CO2/N2 ratio and volatiles contents are positively correlated suggesting condensation in relatively high Au‐grade quartz vein samples (19.5–27.7 ppm Au), while negative correlations suggest boiling with volatile contents less than 1% are indicative of low Au‐grade quartz vein samples (0.14 to 0.18 ppm Au). The elevated CO2 contents observed in the Zuisen veins are signatures of the deeply circulating hydrothermal fluid with a magmatic contribution. Due to intermittent boiling of hydrothermal fluid, CO2 and H2S were partitioned into the vapor phase in deeper portions and condensed into the steam‐heated meteoric water in shallower portions. The signatures of both meteoric and magmatic fluids in fluid inclusion gas compositions were detected in the samples collected near the unconformity between Shimanto Supergroup (shale and sandstone) and Hishikari Lower Andesite. This suggests that a mixing of the deeply circulating hydrothermal fluids with the steam‐heated meteoric water took place near the unconformity, and it was one of the mechanisms to have precipitated gold.

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“…8). Sasaki (2006) demonstrated statistically that the density of veins in the HLA is less than that in the SSG at Hishikari deposit. In the Honko vein system tuff breccia shows more a systematic and distinctive decrease in magnetic susceptibility with decreasing amounts of plagioclase compared with andesite.…”

Section: Discussionmentioning

confidence: 90%

Variations in Chemical Composition of Clay Minerals and Magnetic Susceptibility of Hydrothermally Altered Rocks in the Hishikari Epithermal Gold Deposit, SW Kyushu, Japan

Murakami

2008

Resource Geology

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Hydrothermal alteration, involving chiefl y chlorite and illite, is extensively distributed within host rocks of the Pleistocene Hishikari Lower Andesites (HLA) and the Cretaceous Shimanto Supergroup (SSG) in the underground mining area of the Hishikari epithermal gold deposit, Kagoshima, Japan. Approximately 60% of the mineable auriferous quartz-adularia veins in the Honko vein system occur in sedimentary rocks of the SSG, whereas all the veins of the Yamada vein system occur in volcanic rocks of the HLA. Variations in the abundance and chemical composition of hydrothermal minerals and magnetic susceptibility of the hydrothermally altered rocks of the HLA and SSG were analyzed. In volcanic rocks of the HLA, hydrothermal minerals such as quartz, chlorite, adularia, illite, and pyrite replaced primary minerals. The amount of hydrothermal minerals in the volcanic rocks including chlorite, adularia, illite, and pyrite as well as the altered and/or replaced pyroxenes and plagioclase phenocrysts increases toward the veins in the Honko vein system. The veincentered variation in mineral assemblage is pronounced within up to 25 m from the veins in the peripheral area of the Honko vein system, whereas it is not as apparent in the Yamada vein system. The hydrothermal minerals in sandstone of the SSG occur mainly as seams less than a few millimeters thick and are sporadically observed in halos along the veins and/or the seams. The alteration halos in sandstone of the SSG are restricted to within 1 m of the veins. In the peripheral area of the Honko vein system, chlorite in volcanic rocks is characterized by increasing in Al in its tetrahedral layer and the Fe/Fe + Mg ratio toward the veins, while illite in volcanic rocks has relatively low K and a restricted range of Fe/Fe + Mg ratios. Temperature estimates derived from chlorite geothermometry rise toward the veins within the volcanic rocks. The magnetic susceptibility of tuff breccia of the HLA varies from 21 to less than 0.01 × 10 −3 SI within a span of 40 m from the veins and has signifi cant variation relative to that of andesite (27 -0.06 × 10 −3 SI). The variation peripheral to the Honko vein system correlates with an increase in the abundance of hematite pseudomorphs after magnetite, the percentage of adularia and chlorite with high Fe/Fe + Mg ratios, and the degree of plagioclase alteration with decreasing distance to the veins. In contrast, sedimentary rocks of the SSG maintain a consistent magnetic susceptibility across the alteration zone, within a narrow range from 0.3 to 0.2 × 10 −3 SI. Magnetic susceptibility of volcanic rocks of the HLA, especially tuff breccia, could serve as an effective exploration tool for identifying altered volcanic rocks.

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Statistical Features of Vein Systems in the Hishikari Epithermal Gold Deposit, Japan

Cited by 13 publications

References 23 publications

Use of different forms of waste plastic in concrete – a review

Use of different forms of waste plastic in concrete – a review

Characteristics and Behavior of Hydrothermal Fluids for Gold Mineralization at the Hishikari Deposits, Kyushu, Japan

Variations in Chemical Composition of Clay Minerals and Magnetic Susceptibility of Hydrothermally Altered Rocks in the Hishikari Epithermal Gold Deposit, SW Kyushu, Japan

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