The skarn‐type tungsten deposit of the Date‐Nagai mine is genetically related to the granodiorite batholith of the Iidateyama body. Skarn is developed along the contact between pelitic hornfels and marble that remains as a small roof pendant body directly above the granodiorite batholith. Zonal arrangement of minerals is observed in skarn. The zonation consists of wollastonite, garnet, garnet‐epidote, and vesuvianite‐garnet zones, from marble to hornfels. Sheelite is included in garnet, garnet‐epidote, and vesuvianite‐garnet zones. The oxygen isotope values of skarn minerals were obtained as δ¹⁸O = 4.2–7.7‰ for garnet, 5.9–6.9‰ for vesuvianite, −0.3–3.4‰ for scheelite, 6.0–10.9‰ for quartz, and 8.2‰ for muscovite. The temperature of skarn‐formation was calculated from oxygen isotopic values of scheelite‐quartz pairs to be 288°C. Calculated oxygen isotope values of fluid responsible for skarn minerals were 6.1–9.5‰ for garnet, 1.2–4.8‰ for scheelite, −1.3‐3.6‰ for quartz, and 4.5‰ for muscovite. Garnet precipitated from the fluids of different δ¹⁸O values from scheelite, quartz, and muscovite. These δ¹⁸O values suggest that the origin of fluid responsible for garnet was magmatic water, while evidence for the presence of a meteoric component in the fluids responsible for middle to later stages minerals was confirmed.

中文翻译：

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日本东北日期-长居矽卡岩型钨矿床的氧同位素研究

Date-Nagai矿的矽卡岩型钨矿床与Iidateyama矿体的花岗闪长岩基岩遗传相关。矽卡岩（Skarn）是沿着珍珠岩角质和大理石之间的接触而发展的，而大理石则保留为花岗闪石基岩正上方的小屋顶垂饰。在矽卡岩中观察到矿物质的区域分布。该区域包括从大理石到角砾石的硅灰石，石榴石，石榴石-石榴石和维苏石-石榴石区域。石榴石，石榴石-石榴石和维苏石-石榴石区域中包括白云母。矽卡岩矿物的氧同位素的值分别得到δ ¹⁸石榴石的O = 4.2-7.7‰，维苏石的O = 5.9-6.9‰，白钨矿的-0.3-3.4‰，石英的6.0-10.9‰，白云母的8.2‰。矽卡岩对的氧同位素值计算为矽卡岩形成温度为288°C。矽卡岩矿物的流体计算出的氧同位素值，石榴石为6.1-9.5‰，白钨矿为1.2-4.8‰，石英为-1.3-3.6‰，白云母为4.5‰。石榴石析出从不同δ的流体¹⁸ O值从白钨矿，石英和白云母。这些δ ^18个O值表明，流体负责石榴石的起源是岩浆水，而对于大气成分的负责中旬后期矿物流体存在的证据证实。