Numerous orogenic gold deposits of different age, scale, and mineralization type are located within Northern Transbaikalia. Among them, there is a large group of Early Permian deposits, whose sources and relationships with Late Paleozoic magmatism remain debatable. These issues were solved by the example of the middle-scale (~24 t, Au) Irokinda deposit, localized within the Precambrian rocks of the Baikal–Muya Terrane. 39Ar–40Ar geochronological dating of the ore-hosting altered rocks indicates that hydrothermal–metasomatic process took place about 270 myr ago. Gold mineralization has heterogeneous Pb-, S-, Sr-, and Nd-isotopic characteristics. Variations in the Pb, S, Sr, and Nd isotopic composition of ore and gangue minerals suggest that the mineral-forming components were involved in the hydrothermal system from different sources. Among them, the leading role belonged to the rocks of the Precambrian crust of the Baikal–Muya Terrane. Pb isotopic composition of the second identified source is close to that of the Early Permian alkaline and subalkaline rocks of the Baikal–Muya Terrane. This fact may indicate a genetic relationship between the Irokinda gold mineralization and intraplate alkaline magmatism, which developed in the region simultaneously with ore-forming processes.

中文翻译：

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北外贝加尔半岛 Irokinda 矿床金矿化的来源和时代：来自 Pb、S、Sr 和 Nd 同位素地球化学和 39Ar–40Ar 年代学数据的证据

许多不同年龄、规模和矿化类型的造山金矿床位于北外贝加尔地区。其中，有一大群早二叠世矿床，其来源及与晚古生代岩浆活动的关系尚有争议。这些问题通过位于贝加尔湖-穆亚地体前寒武纪岩石中的中等规模（~24 吨，金）Irokinda 矿床的例子得到解决。含矿蚀变岩的 39Ar–40Ar 年代学表明，热液交代过程发生在大约 270 myr 之前。金矿化具有不均匀的 Pb-、S-、Sr- 和 Nd-同位素特征。矿石和脉石矿物的 Pb、S、Sr 和 Nd 同位素组成的变化表明，矿物形成成分参与了不同来源的热液系统。他们之中，主要作用属于贝加尔湖-木雅地体前寒武纪地壳的岩石。已确定的第二个来源的铅同位素组成与贝加尔湖-木雅地体早二叠世碱性和亚碱性岩石的铅同位素组成接近。这一事实可能表明 Irokinda 金矿化与板内碱性岩浆作用之间存在成因关系，后者在该地区与成矿过程同时发育。