岩浆通道成矿核心内涵“两深一浅一通道”及其找矿意义  

The core connotation of magma conduit model“two deep,one shallow and single channel”and its significances on exploration

作　　者：宋谢炎[1] SONG Xieyan(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550081,China)

机构地区：[1]中国科学院地球化学研究所,矿床地球化学国家重点实验室,贵州贵阳550081

出　　处：《地质学报》2024年第7期1941-1952,共12页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42330807,42121003)资助的成果。

摘　　要：岩浆通道成矿模型的建立深刻改变了岩浆铜镍硫化物矿床成因研究的范式,成为该领域的研究前沿,而且已经成功地应用于找矿勘查中。该模型揭示了硫化物熔离与聚集成矿在空间上的不一致性以及成矿与相关玄武岩铂族元素强烈亏损的成因联系,很好地解释了为什么很多含矿岩体围岩贫硫化物的现象。笔者将该模型的核心内涵概括为“两深一浅一通道”,“两深”指成矿物质来源于地幔、硫化物熔离发生在深部,“一浅”指硫化物的聚集成矿主要发生在较浅的岩浆房,“一通道”指较稳定的岩浆通道更有利于成大矿。结合对典型矿床和成矿带的分析,笔者提出侵位较浅的、规模相对较大的岩体,其成矿潜力好于深部的岩浆通道相。因此,认为地表矿化并不是唯一可靠的、甚至不能作为最重要的找矿标志,要提高找矿效率(特别是隐伏矿床),首先要全面分析成矿带岩浆通道系统在不同区域的埋藏、剥蚀和暴露状况,目标岩体地质产状及其与围岩时代差异等宏观地质要素,查明深部通道相与浅部岩体空间分布和形成深度的差异,在此基础上,判断浅部岩体的位置、合理部署重点勘查区域、选择有效的勘查技术、定位目标岩体,进行钻探验证。The magma conduit model has profoundly impacted the understanding of magmatic NiCu sulfide deposit formation,establishing a new paradigm for research and exploration in this field.This model elucidates the decoupling of sulfide liquid segregation from its accumulation,thereby establishing a direct genetic link between the formation of such deposits and the depletion of platinumgroup elements in related basalts.Furthermore,it provides a compelling explanation for the consistently low sulfide content observed in the wall rocks of the mineralized intrusions.This paper summarizes the core connotation of the magma conduit model as“two deep,one shallow,and a single channel.”The“two deep”principle refers to the mantle origin of metallogenic materials and the depthdependent segregation of sulfide liquids during magma processes.The“one shallow”refers to the accumulation of sulfide liquids at relatively shallow depths.Finally,the“single channel”means that a positionally stable magma conduit is more beneficial to the formation of large ore deposit.An analysis of classic deposits and metallogenic belts suggests that relatively large intrusions emplaced in shallower crustal depths exhibit a greater mineralization potential compared to channel facies situated at deeper levels.This observation underscores the fact that surface mineralization is not a reliable,or even indicative,factor for prospecting.To optimize the efficiency of prospecting,particularly for concealed ore deposits,it is essential to meticulously assess the burial and exposure status of the magma conduit system across various locations within a metallogenic belt.Determining the characteristics,distribution,and original depths of the magma channel within both deep and shallow intrusions is crucial.This knowledge will enable the targeted selection of key areas and the application of appropriate exploration techniques,ultimately guiding prospecting drilling programs towards the most promising intrusions.

关 键 词：岩浆铜镍硫化物矿床 岩浆通道成矿模型 含矿岩体产状 侵位深度 围岩时代 

分 类 号：P612[天文地球—矿床学]