斑岩-矽卡岩型钼矿成矿控制因素  

Controlling factors on the formation of porphyry-skarn Mo deposits

作　　者：欧阳荷根[1] OUYANG He-gen(MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《矿物岩石地球化学通报》2024年第2期271-281,I0002,共12页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家重点研发计划项目(2017YFC0601403);国家自然科学基金资助项目(42372096);中央级科研院所基本科研业务费资助项目(KK2203)。

摘　　要：本文从成钼矿岩浆的化学组分和物理化学性质,以及成钼矿流体的出溶和金属堆积过程两个层次,探讨了斑岩-矽卡岩型钼矿的成矿控制因素。研究揭示,不同构造环境中的斑岩-矽卡岩型钼矿的成矿岩浆均不富集钼,氧化性富水岩浆是形成斑岩-矽卡岩型钼矿的基础,成矿流体沿岩浆房顶部衍生的小岩株高度聚集是成钼矿之关键环节。研究还揭示,大型-超大型斑岩-矽卡岩型钼矿均具有多期岩浆-热液活动叠加成矿的特点,成矿岩体与大岩浆房相连,并且成矿岩浆能多期侵位与成矿,是形成大型-超大型钼矿的关键因素。综合来看,斑岩-矽卡岩型钼矿是岩浆体量、岩浆氧逸度和水含量、流体聚集程度以及多期岩浆-热液活动叠加成矿多因素耦合的产物。岩浆体量、岩浆氧逸度和岩浆水含量是基础,流体聚集程度是关键,要形成大型-超大型斑岩-矽卡岩型钼矿,还需要多期岩浆-热液活动的叠加成矿。研究提出,寻找斑岩-矽卡岩型钼矿,在关注岩体地球化学属性的同时,还应关注岩体的空间结构属性以及多期岩浆-热液活动叠加成矿特征的识别。In this paper,the controlling factors for the formation of porphyry-skarn Mo deposits have been discussed based on investigations of chemical compositions and physicochemical properties of ore-forming magmas and processes of the fluid exsolution and metal precipitation.The results show that Mo was generally depleted in ore-forming magmas of various porphyryskarn Mo deposits in different tectonic settings.Oxidizing water rich magma is the basis for the formation of porphyry-skarn Mo deposits.The high ore-forming focusing degree along small stocks derived originally from top parts of the deep-sited magma chambers was the critical link for the formation of porphyry-skarn Mo deposits.It is also shown that large to super-large sized porphyry-skarn Mo deposits are commonly characterized with the multi-stage magmatic-hydrothermal superimposed metallogeny and magmas of their ore-forming porphyry stocks were connected with large magma chambers.In addition,their ore-forming magmas resulted in multiple-phases intrusions and metallogenies which are key factors for the formation of large to super-large sized porphyry-skarn Mo deposits.In summary,the porphyry-skarn Mo deposit was the coupling product of various factors including the magmatic volume,magmatic oxygen fugacity,magmatic water content,ore-forming fluid accumulation degree,and the superposition mineralization of multi-stage magmatic-hydrothermal activities.Among them,the magma chamber volume,magmatic oxygen fugacity and magmatic water content are basic factors,the ore-forming fluid focusing degree is a critical factor,and the superposition mineralization of multi-stage magmatic-hydrothermal activities is a key factor mostly required for the formation of large to super-large sized porphyry-skarn Mo deposits.Moreover,it is suggested that in the search for porphyry-skarn Mo deposits,attention should be paid to the geochemical properties and spatial structure properties of porphyry stocks,and the identification of superimposition metallogenic characteristics of multi-sta

关 键 词：斑岩-矽卡岩型钼矿 熔体钼含量 岩浆体量 流体聚集程度 多期岩浆-热液活动 

分 类 号：P618.65[天文地球—矿床学]