岩浆演化过程中硫化物饱和对斑岩型Cu-Au矿床形成的控制  

Control of Sulfide Saturationon the Formation of Porphyry Cu-Au Deposits During MagmaticEvolution

作　　者：陈浩宇 和文言[1,2,3] CHEN Haoyu;HE Wenyan(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Beijing),Beijing100083,China;.Frontiers Science Center for Deep-time Digital Earth,China University of Geosciences(Beijing),Beijing100083,China;.School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing100083,China)

机构地区：[1]中国地质大学(北京)地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学(北京)深时数字地球科学前沿科学中心,北京100083 [3]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《现代地质》2024年第4期947-958,共12页Geoscience

基　　金：国家重点研发计划项目(2022YFF0800902,2019YFA0708603);国家自然科学基金项目(42372098)。

摘　　要：斑岩型矿床是全球铜、金、银、钼等战略性矿产的重要来源,其主要分布于汇聚板块边缘。已有研究揭示大型斑岩矿床一般起源于板片俯冲产生的岩浆作用,俯冲板块脱水诱发地幔楔部分熔融形成初始弧岩浆,在经历过一系列复杂的演化后,最终上升至近地表(3~5 km)成矿。而岩浆硫化物能强烈络合亲铜元素,对岩浆演化过程金属的富集起着重要作用,研究硫化物中亲铜元素富集与活化过程是揭示斑岩矿床成矿机理的重要一环。本文对近年来斑岩矿床中岩浆硫化物的研究成果进行系统总结,梳理硫化物饱和的控制因素与分异过程,对比分析岩浆硫化物饱和过程对斑岩矿床金属富集的控制。岩浆硫化物饱和受温度、压力、氧逸度等多种因素共同控制,其中氧逸度变化是导致硫化物饱和的关键;硫化物饱和将促使金属Cu、Au、PGE等高效浓聚,PGE元素和Au对硫化物饱和异常敏感,少量硫化物饱和会导致大量PGE和Au聚集。岩浆硫化物饱和过程对斑岩成矿潜力影响存在争议,一些研究认为硫化物饱和是斑岩成矿的关键步骤,因为饱和的硫化物将促使金属Cu、Au高效浓聚,当新的岩浆注入或岩浆氧逸度或硫逸度变化时,硫化物将被再次溶解使成矿金属重新在硅酸盐熔体中富集;一些研究则认为岩浆演化过程中硫化物饱和不妨碍斑岩成矿,因为早期少量硫化物饱和沉淀并不会降低剩余岩浆中成矿元素丰度,不影响成矿潜力。厚地壳中硫化物饱和一般发生在早期,薄地壳中硫化物在晚期饱和。Porphyry deposits are important sources of global copper,gold,silver,molybdenum,and other stra-tegic minerals/metals,and they are mainly distributed along convergent plate margins.Previous studies have revealed that large porphyry deposits generally originate from arc magmatism due to plate subduction,and the mineralization mostly take place at near-surface(~3-5 km).Magmatic sulfides can strongly concentrate chalcophile elements,which play important roles in metal enrichment during magmatism.Studying the enrich-ment and activation processes of chalcophile elements in sulfides is key to understanding the metallogenic mech-anism of porphyry deposits.In this paper,we systematically summarize previous studies on magmatic sulfides in porphyry deposits,investigate the controlling factors and differentiation processes of sulfide saturation,and com-pare and analyze the controls of magmatic sulfide saturation processes on metal enrichment in porphyry deposits.Magmatic sulfide saturation can be controlled by various factors such as temperature,pressure,and oxygen fu-gacity,with oxygen fugacity being the key to sulfide saturation.Sulfide saturation will promote the efficient con-centration of metals such as Cu,Au,and PGE.Particularly,PGE and Au are extremely sensitive to sulfide saturation,and slight sulfide saturation will lead to the aggregation of a large amount of PGE and Au metals.The influence of magmatic sulfide saturation on porphyry mineralization potential is controversial.Some studies conclude that sulfide saturation is the key step in porphyry mineralization because saturated sulfide promotes the concentration of metals Cu and Au.When new magma is injected or when the oxygen or sulfur fugacity of mag-ma changes,sulfide will dissolved again,causing ore-forming metals to become enriched in the silicate melt once more.Other studies conclude that sulfide saturation does not hinder porphyry mineralization during mag-matic evolution because a small amount of sulfide saturation and precipitation in the early stage will

关 键 词：岩浆硫化物 斑岩矿床 亲铜元素 弧岩浆 

分 类 号：P611.11[天文地球—矿床学] P612[天文地球—地质学]