Abstract

The Varvarinskoye copper–gold deposit, large in terms of Au and small in terms of Cu, was discovered in 1979 in the western part of the Torgai trough in Kazakhstan. It is composed of Devonian volcanosedimentary and intrusive rocks. Ore zones with a thickness from a few meters to a few tens of meters have been identified against a background of disseminated ore mineralization. They are composed of densely disseminated (porphyry) up to massive ores. The ore zones are localized in the thermal metamorphism band of volcanosedimentary and intrusive rocks, while disseminated mineralization is widespread beyond it. Ten ore mineralization types can be distinguished. The Au–Cu mineralization type is common in volcanosedimentary rocks and diorites, while the Au–Cu–Ni ores occur in serpentinites formed after thermally metamorphized intrusive rocks. Densely disseminated and massive magnetite ores are confined to skarns. Sulfide and sulfide–arsenide mineralization can also be observed. Each type of Au–Cu mineralization (pyrrhotite, chalcopyrite–marcasite–pyrite, pyrite, and gold–sulfide–arsenopyrite) can be correlated to an analog of Au–Cu–Ni mineralization (pentlandite–pyrrhotite, chalcopyrite–pentlandite–pyrite, pentlandite–pyrite, and gold–nickeline–gersdorffite). This indicates the uniform ore-forming process in serpentinites and volcanosedimentary rocks with diorites and borrowing of ore material from host rocks, at least, partially. The gold–chalcopyrite mineralization type, synchronous to the thermal metamorphism and analogous to mineralization of the alkali stage at porphyry copper deposits, has no analog in the Au–Cu–Ni mineralization. Gold is present in all mineralization types, but gold–chalcopyrite and sulfide–arsenide are the most enriched in Au. Eighty ore minerals have been found at the studied deposit. Pyrrhotite disulfidization and chalcopyrite pyritization are universal in occurrence. These processes likely led to the formation of chalcopyrite–marcasite–pyrite and chalcopyrite–pentlandite–pyrite mineralization after pyrrhotite and pentlandite–pyrrhotite types, respectively. Invisible gold present in chalcopyrite was enlarged during these processes.

中文翻译：

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哈萨克斯坦北部的Varvarinskoye复杂铜金矿床：矿物类型和矿石组成

摘要

1979年在哈萨克斯坦的托尔盖（Torgai）槽西部发现了Varvarinskoye铜金矿床，其金含量大，而铜含量小。它由泥盆纪火山岩和侵入岩组成。在散布的矿石矿化的背景下，已经确定了厚度从几米到几十米的矿石区。它们由密集散布的（斑岩）直至块状矿石组成。矿区位于火山岩和侵入岩的热变质带中，而散布的矿化作用则超出了它。可以区分十种矿化类型。在火山沉积岩和闪长岩中，Au-Cu的矿化类型很普遍，而在热变质侵入岩形成的蛇纹岩中，Au-Cu-Ni矿产。密集散布的块状磁铁矿被限制在矽卡岩中。也可以观察到硫化物和硫化物-砷的矿化作用。每种类型的Au-Cu矿化（硫铁矿，黄铜矿-镁铁矿-黄铁矿，黄铁矿和金-硫化物-砷黄铁矿）都可以与Au-Cu-Ni矿化的类似物（戊铁矿-黄铁矿，黄铜矿-膨润土-黄铁矿，黄铁矿–黄铁矿和金–镍镍矿– Gersdorffite）。这表明蛇纹岩和火山沉积岩中有闪长岩的均匀成矿过程，以及至少部分地从宿主岩中借用了矿石物质。金-黄铜矿的矿化类型与斑岩铜矿床的热变质同步且类似于碱阶段的矿化，在金-铜-镍矿化中没有类似物。金存在于所有矿化类型中，但是金-黄铜矿和硫化物-砷含量最丰富。在所研究的矿床中发现了80种矿石。滑铁矿二硫化和黄铜矿黄铁矿化普遍发生。这些过程可能分别导致了黄铁矿和绿铁矿-黄铁矿类型后的黄铜矿-镁铁矿-黄铁矿和黄铜矿-膨润土-黄铁矿矿化的形成。在这些过程中，黄铜矿中存在的看不见的金会增大。这些过程可能分别导致了黄铁矿和绿铁矿-黄铁矿类型后的黄铜矿-镁铁矿-黄铁矿和黄铜矿-膨润土-黄铁矿矿化的形成。在这些过程中，黄铜矿中存在的看不见的金会增大。这些过程可能分别导致了黄铁矿和绿铁矿-黄铁矿类型后的黄铜矿-镁铁矿-黄铁矿和黄铜矿-膨润土-黄铁矿矿化的形成。在这些过程中，黄铜矿中存在的看不见的金会增大。