Submillimeter Scale Variation of Oxygen Isotope of Vein Quartz at the Hishikari Deposit, Japan |
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| Authors: | Ken–ichiro HAYASHI Tohru MARUYAMA Hisao SATOH |
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| Institution: | Department of Mineralogy, Petrology, and Economic Geology, Graduate School of Science, Tohoku University, Aoba–ku, Sendai 980–8578, Japan [e-mail: ] |
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| Abstract: | Abstract: The physical and chemical mechanism of gold precipitation in the typical low-sulfidation epithermal gold deposit at the Hishikari mine was quantified by submillimeter scale oxygen isotope analyses of vein quartz. In situ CO2 laser-ablated fluorination was used to measure temporal δ18O excursions. The calculated oxygen isotopic compositions of the ore-forming fluid indicate a dynamic process of epithermal vein formation. Intermittent opening of the vein allowed introduction of metal-bearing deep fluid to the epithermal system, and associated boiling and subsequent mixing with meteoric water caused precipitation of precious metals. |
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| Keywords: | Hishikari deposit gold mineralization low sulfida-tion style oxygen isotope magmatic water meteoric water |
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