Mineralogy, sulfur isotope and fluid inclusion studies of hydrothermal ore at the Hakurei deposit, Bayonnaise knoll, Izu-Bonin arc
Mineralogy, sulfur isotope and fluid inclusion studies of hydrothermal ore at the Hakurei deposit, Bayonnaise knoll, Izu-Bonin arc
复制标题
伊豆-博宁弧博丽矿床热液矿石的矿物学、硫同位素和流体包裹体研究
作者：
Watanabe;S. and K. Hayashi;K.
对采自巴约内斯丘陵Hakurei存款的硫化物和硫酸盐矿石样品进行了矿物产状和化学成分的研究，包括硫同位素和流体包裹体的显微测温。块状硫化物矿石、矿化火山岩和硬石膏矿石从海底到取芯样品底部依次递减。块状硫化物矿石以闪锌矿为主，并伴有砷黝铜矿、黄铜矿和黄铁矿，少量方铅矿、硫砷铜矿和铜蓝。无定形二氧化硅通常沉淀在硫化物矿物的表面上。含砷矿物如砷黝铜矿、硫砷铜矿和硫锑铅矿很常见，而方铅矿和富锑黝铜矿则很少见。矿物的丰度和化学成分与存款烟囱中发现的不同。硫化物矿物硫同位素组成为+3.1 ‰ ~ 5.2 ‰，硫酸盐矿物硫同位素组成为+19.6 ‰ ~ 21.8 ‰。硫同位素的均匀性表明，结合在Hakurei存款来自海水中的硫酸盐水溶液的还原硫。
Sulfide and sulfate ore samples collected from the Hakurei deposit of the Bayonnaise knoll were examined for the occurrence and chemical composition of minerals, including the sulfur isotopes and the microthermometry of fluid inclusions. Massive sulfide ore, mineralized volcanic rock, and anhydrite ore occur in descending order, from the seafloor to the bottom of the cored sample. The massive sulfide ore is dominated by sphalerite and accompanied by tennantite, chalcopyrite, and pyrite with lesser amounts of galena, enargite, and covellite. Amorphous silica is commonly precipitated on the surface of the sulfide minerals. As‐bearing minerals such as tennantite, enargite, and luzonite are common, while galena and Sb‐rich tetrahedrite are scarce. The mineral abundance and chemical composition of the minerals differs from that found in chimneys of the deposit. The sulfur isotope compositions in the minerals are +3.1–5.2‰ for sulfides and +19.6–21.8‰ for sulfate minerals. The homogeneous nature of the sulfur isotopes suggests that sulfur incorporated in the Hakurei deposit came from the reduction of aqueous sulfate in seawater.