云南维西地区锑金多金属矿成矿规律研究

Study on Metallogenic Regularity of Antimony-Gold Polymetallic Deposits in Weixi Area, Yunnan

摘要: 云南维西地区位于西南三江成矿带中段澜沧江褶皱带，是我国重要的中低温热液多金属成矿集中区，长期以来受限于复杂的地质构造条件和单一的找矿思路，锑金多金属矿勘查进展缓慢。本文基于区域成矿演化背景、典型矿床解剖、地球化学异常响应及控矿要素系统分析，构建了“地层–构造–岩浆–流体”四位一体综合信息找矿模型，突破了三江成矿带传统“笔架山式”单一沉积改造型锑矿、华南“木利式”单一热液蚀变型锑矿的找矿局限，明确了印支期俯冲带构造活动驱动的岩浆热液与二叠系含矿地层耦合控矿的核心机制，阐明了锑–金–铅锌多金属共生分异受成矿流体氧逸度、硫逸度联合制约的规律，给三江中段锑金多金属矿系统成矿预测提供思路。通过忍根河矿段原生晕垂向分带研究，识别出“前缘晕As-Sb-Hg-近矿晕Au-Ag-Pb-Zn-尾晕Co-Ni-Cr”的完整分带序列，并在已知矿体尾部发现前缘晕与尾晕元素叠加的地球化学参数反转现象，为深部隐伏矿体定位提供了关键依据。成果为维西地区上怒洛矿区勘查部署提供了直接科学依据，也为三江成矿带中段同类型矿床找矿突破提供了可借鉴的技术方法。

Abstract: The Weixi area in Yunnan Province is located in the Lancang River fold belt in the middle part of the Sanjiang metallogenic belt in Southwest China. It is an important medium-low temperature hydrothermal polymetallic metallogenic concentration area in China. For a long time, due to complex geological structural conditions and single prospecting ideas, the exploration of antimony-gold polymetallic deposits has been slow. Based on the systematic analysis of regional metallogenic evolution background, typical deposit anatomy, geochemical anomaly response and ore-controlling factors, this paper constructs a four-in-one comprehensive information prospecting model of “strata-structure-magma-fluid”, which breaks through the prospecting limitations of the traditional “Bijiashan type” single sedimentary transformation type antimony deposit in Sanjiang metallogenic belt and the “Muli type” single hydrothermal alteration type antimony deposit in South China. The core mechanism of ore-controlling coupling between magmatic hydrothermal fluid driven by tectonic activity of Indosinian subduction zone and Permian ore-bearing strata is clarified, and the law that the symbiotic differentiation of antimony-gold-lead-zinc polymetallic is jointly restricted by the oxygen fugacity and sulfur fugacity of ore-forming fluid is clarified. It provides ideas for metallogenic prediction of antimony-gold polymetallic ore system in the middle section of Sanjiang. Through the study of the vertical zoning of the primary halo in the Rengenhe ore section, the complete zoning sequence of “front halo As-Sb-Hg-near halo Au-Ag-Pb-Zn-tail halo Co-Ni-Cr” was identified, and the geochemical parameter inversion phenomenon of the superposition of front halo and tail halo elements was found at the tail of the known ore body, which provided a key basis for the location of deep concealed ore bodies. The results provide a direct scientific basis for the exploration and deployment of the Shangnuluo mining area in the Weixi area, and also provide a technical method for the prospecting breakthrough of the same type of deposits in the middle section of the Sanjiang metallogenic belt.