滇西马厂箐钼铜金矿床深部地质过程的系列成矿效应  

Series Metallogenic Effect of Deep Geological Processes in the Machangqing Mo-Cu-Au Deposit,Western Yunnan Province

作　　者：肖继雄[1] 刘显凡[1,2] 卢秋霞[1] 吴冉[1] 赵甫峰[1] 李春辉[1] 楚亚婷[1] 蔡永文[1] 蔡飞跃[1] 

机构地区：[1]成都理工大学地球科学学院,四川成都610059 [2]南京大学内生金属矿床成矿机制研究国家重点实验室,江苏南京210093

出　　处：《地质与勘探》2012年第3期546-561,共16页Geology and Exploration

基　　金：国家自然科学基金项目(批准号:40473027;40773031);教育部博士点基金联合资助项目(20105122110010);南京大学内生金属矿床成矿机制研究国家重点实验室开放研究基金项目(编号:14-08-3);成都理工大学矿物学岩石学矿床学国家重点(培育)学科建设项目(编号:SZD0407)联合资助

摘　　要：马厂箐钼铜金矿床是金沙江-哀牢山断裂带上与喜马拉雅期富碱斑岩有关的典型矿床之一,其成矿作用具有特殊性。本文应用透岩浆流体成矿理论,重点探讨了马厂箐钼铜金矿床深部地质过程中成岩与由地幔流体作用引发壳幔混染并形成系列成矿的关系。通过对马厂箐矿床成岩成矿时代的厘定、岩矿石稀土和微量元素、稀有气体及Pb-Sr-Nd同位素研究,论证了成矿流体和岩浆流体均来自于富集地幔,这种成矿流体是包含于富碱岩浆并与其互不混溶的地幔流体。在上升运移过程中,地幔流体可随富碱岩浆的结晶成岩过程对岩体进行同步自交代蚀变而在斑岩体内或其深部形成矿床;也可与岩浆分离而独立运移,在岩体与围岩的接触带及地层围岩中进行交代蚀变成矿。在这一成岩成矿过程中,引发并促进壳幔物质混染和叠加成矿,由此导致了马厂箐矿区成矿分带表现为从岩体到围岩、从高温到低温的不同矿种和不同类型的系列成矿效应。The Machangqing Mo-Cu-Au deposit is a typical deposit related to the Himalayan alkaline-rich porphyries along the Jinshajiang-Ailaos- han fault zone. It has some special metallogenic features with respect to other deposits. The purpose of this paper is to study the relationship between crys- tallization diagenesis during deep geological process and metallogenesis in crustal-mantle contamination caused by mantle fluid in Machangqing ore deposit based on the transmagmatic fluid metallogenic theory. The approaches used include geochronology of crystallization diagenesis and metallogenesis, REE, trace element, noble gas and Pb-Sr-Nd isotopic geochemistry. The result shows that both the ore-forming fluid and magmatic fluid are derive from enriched mantle, and the ore-forming fluid is mantle fluid which was wrapped in and unmixed with the alkali-rich magma. As the fluid transported up- wards, the alkali-rich porphyries were synchronically self-replaced and alterated by the mantle fluid during the process of alkali-rich magma crystallizing and diagenesis, forming deposits in magma bodies or at depth. In addition, the mantle fluid could escape from magma and transport independently, and the metasomatic alteration occurred in the contact zone between magma bodies and wall rocks or rocks in strata. In the processes of diagenesis and metallo- genesis, metallogenetic overlapping in crustal-mantle contamination was spawned and promoted. As a result, from the magatite bodies to the wall rocks, the metallogenic temperature changed from high to low to produce different commodities and types of metallogeuetic effects in different localizations as a kind of series mineralization.

关 键 词：富碱岩浆 地幔流体作用 系列成矿效应 马厂箐矿床 滇西地区 

分 类 号：P612[天文地球—矿床学]