Abstract

The article discusses a novel methodological approach to deciphering the evolution of ore-magmatic systems (OMS), based on the study of geochemical fields associated with different stages of the evolution of the magma chamber, accompanied by ore mineralization. As the material for research, we used the results of geochemical dispersion train surveys within the Kara ore cluster (Eastern Transbaikalia). The analysis of features of the composition and sequence of identification of geochemical fields made it possible to consider in more detail the evolution of the Kara OMS. It was found that we are dealing with a highly eroded rare metal OMS created in two ore formation stages. The first ore formation stage is associated with the evolution of the upper magma chamber (apical part of the Kara–Chacha massif). The main useful component of this OMS was Mo. The second stage is associated with the evolution of the lower magma chamber. This was also rare-metal mineralization; its profiling elements were W and Mo, but the main useful component is Au. It was found that Au is mobile at two evolutionary stages of the late OMS and accumulates when one stage of mineralization overprints the other. Granitoids of the Kara–Chacha massif can be considered the source of Au. No less probable is the hypothesis of its input together with B from the lower levels of the magmatic system, or as part of transmagmatic fluids from without.

中文翻译：

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喀拉矿-岩浆系统演化（俄罗斯东部外贝加尔）：应用小尺度地球化学调查的经验

摘要

本文讨论了一种破译矿石-岩浆系统 (OMS) 演化的新方法论方法，该方法基于对伴随矿石成矿的岩浆房演化不同阶段相关的地球化学场的研究。作为研究材料，我们使用了喀拉矿群（Eastern Transbaikalia）内地球化学弥散序列调查的结果。通过对地球化学场的组成特征和序列特征的分析，可以更详细地考虑卡拉OMS的演化。发现我们正在处理在两个成矿阶段产生的高度侵蚀的稀有金属 OMS。第一成矿阶段与上岩浆房（Kara-Chacha 地块的顶端部分）的演化有关。该 OMS 的主要有用成分是 Mo。第二阶段与下部岩浆房的演化有关。这也是稀有金属矿化；它的分析元素是 W 和 Mo，但主要有用的成分是 Au。发现 Au 在 OMS 晚期的两个演化阶段是可移动的，并在一个矿化阶段叠加到另一个阶段时积累。Kara-Chacha 地块的花岗岩可以被认为是 Au 的来源。同样可能的假设是它与 B 一起来自岩浆系统较低层的输入，或者作为来自外部的跨岩浆流体的一部分。发现 Au 在 OMS 晚期的两个演化阶段是可移动的，并在一个矿化阶段叠加到另一个阶段时积累。Kara-Chacha 地块的花岗岩可以被认为是 Au 的来源。同样可能的假设是它与 B 一起来自岩浆系统较低层的输入，或者作为来自外部的跨岩浆流体的一部分。发现 Au 在 OMS 晚期的两个演化阶段是可移动的，并在一个矿化阶段叠加到另一个阶段时积累。Kara-Chacha 地块的花岗岩可以被认为是 Au 的来源。同样可能的假设是它与 B 一起来自岩浆系统较低层的输入，或者作为来自外部的跨岩浆流体的一部分。