Abstract

New data are obtained on the age of the epithermal gold-silver mineralization of the Kubaka deposit (Omolon Massif, Northeast Russia). Our geological observations in the open-pit mine of the Zokol zone of the deposit allow us to conclude that the mineralization formed between the eruptions of Upper Devonian ore-hosting volcanites of the Kedon series (zircon U-Pb age ~ 370 ± 2.5 Ma, SHRIMP) and Lower-to-Middle Jurassic trachybasalts and picrobasalts of the Omolon Complex (⁴⁰Ar/³⁹Ar plateau age of 179 ± 8 Ma) without the vein penetrating into the Carboniferous Corba Formation. The ⁴⁰Ar/³⁹Ar plateau age for a white adularia from the productive quartz vein yielded 299 ± 3.5 Ma (MSWD = 0.91, p = 0.43, 66% of ³⁹Ar released in four steps). Our results contradict a commonly accepted concept of “polychronous” ore formation (during the Carboniferous and Cretaceous) or long-term mineralization at the Kubaka deposit, and likely indicate a high probability of at least an Upper Carboniferous upper age limit of epithermal gold mineralization.

中文翻译：

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库巴卡超热金银矿床的年龄（俄罗斯东北部的Omolon Massif）：地质和同位素-年代学约束（U-Pb和40 Ar / 39 Ar方法）

摘要

获得了有关库巴卡矿床（俄罗斯东北部的Omolon Massif）的超热金银矿化年龄的新数据。我们在该矿床Zokol带露天矿山中的地质观察结果使我们可以得出结论，即在Kedon系列上泥盆纪含矿火山岩喷发（锆石U-Pb年龄〜370±2.5 Ma， SHRIMP）和Omolon复杂区的中侏罗纪次长玄武岩和微玄武岩（⁴⁰ Ar / ³⁹ Ar高原年龄179±8 Ma），而静脉未渗透到石炭纪的科尔巴组。来自生产石英脉的白色砾石的⁴⁰ Ar / ³⁹ Ar高原期产生299±3.5 Ma（MSWD = 0.91，p = 0.43，66 ％^分四步释放³⁹ Ar。我们的结果与普遍接受的“多时代”矿石形成（在石炭纪和白垩纪期间）或库巴卡矿床的长期矿化概念相矛盾，并且可能表明至少有较高的石炭纪高温成矿年龄上限。