Abstract

We analyze and generalize new data inferred from the geological, geochronological, and metallogenic studies performed in recent decades on igneous rocks of the Iorokhan gold-bearing complex in the eastern Bureya Massif. It is shown that four phases are determinative of the structure of the Iorokhan complex of minor intrusions whose rocks are referred to hypabyssal and subvolcanic intrusive facies. Specific features of their rock composition and structural tectonic conditions of localization are described and geological and geochronological (103 ± 1.0-97.4 ± 6.5 Ma) data on their Late Albian–Early Cenomanian age are presented. Based on the alumina, calcium, and alkali ratio, the major part of their compositions corresponds to the I-type (A/CNK < 1.1) high-alumina magnesia and magnesia–ferruginous varieties with decreased HFSE concentrations, including HREE. Melts formed due to amphibolite source melting might have been the deep sources of the Iorokhan diorites. The Noni deposit is briefly described and the main localization factors of the gold-ore mineralization are considered. The Iorokhan magmatite areals of the East Bureya Volcano–Plutonic Zone may be considered as one of the fragments of the structure bordering between the continental margin of the Bureya Massif and the accretionary prisms of the Sikhote Alin Orogenic Belt. The Iorokhan complex of minor intrusions is assumed to be a small fragment of an extensive band of Late Albian–Early Cenomanian magmatites developed in southern Far East Russia that originated under the transform continental marginal setting, and a combination of synstrike–slip compression and extension zones typical of such margins with further development of the pull-apart depressions.

中文翻译：

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Bureya地块东部的小规模侵入的Iorokhan复合体：地质，年龄和金矿化

摘要

我们分析并归纳了从最近几十年对东比雷亚山地块Iorokhan含金复合体的火成岩进行的地质，地质年代和成矿研究得出的新数据。结果表明，四个阶段决定了次要侵入的Iorokhan复合体的结构，其岩石被称为海底和火山下侵入相。描述了它们的岩石成分的特定特征和结构化的局部构造条件，并给出了其晚阿比安至早塞诺曼时代的地质和年代学数据（103±1.0-97.4±6.5 Ma）。根据氧化铝，钙和碱的比例，其组成的主要部分对应于HFSE浓度降低的I型（A / CNK <1.1）高铝氧化镁和氧化镁铁质品种，包括HREE。由于角闪石来源的熔融而形成的熔体可能是Iorokhan闪长岩的深层来源。简要描述了诺丽山矿床，并考虑了金矿石矿化的主要定位因素。东布列亚火山-俯冲带的约鲁汗岩浆岩地区可被认为是布列亚地块大陆边缘与锡霍特阿林造山带增生棱镜之间边界的结构碎片之一。俄罗汉（Iorokhan）的小规模侵入复合体被认为是在远东俄罗斯边缘地区形成的，在俄罗斯远东南部发展的晚阿尔比－早切诺曼尼亚岩浆岩广泛带的一小部分，