俄罗斯塔尔纳赫岩浆铜镍硫化物矿床中流体参与成矿的矿物学证据  

Mineralogical evidence for fluid activities in the metallogeny of the Talnakh magmatic Cu-Ni sulfide deposit in Norilsk,Russia

作　　者：蒋俊毅[1] 苏尚国[1] 王菁姣 JIANG Junyi;SU Shangguo;WANG Jingjiao(School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Literature and Data Department,Geosciences Documentation Center of China Geological Survey,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质调查局文献中心文献数据室,北京100083

出　　处：《地学前缘》2019年第6期228-243,共16页Earth Science Frontiers

基　　金：中国地质调查局项目(12120115069701);国家自然科学基金项目(41272105)

摘　　要：岩浆铜镍硫化物矿床研究中"硫化物矿浆"组成及上侵聚集机制一直存在争议。在新近提出的"岩浆通道成矿系统"的思路下,文章研究了来自俄罗斯诺里尔斯克地区塔尔纳赫铜镍硫化物矿床中的赋矿橄榄苏长辉长岩,发现其主要造岩矿物存在两种类型,在微量元素分配上出现了明显的差异。文章重点报告了其中斜长石的特点。以微量元素的分配模式为依据,所有斜长石可以分为两类:Ⅰ型斜长石强烈富集大离子亲石元素和轻稀土元素,强烈亏损高场强元素,成分为钠长石-倍长石,与硫化物共存,指示在含矿硫化物珠滴中应含有大量流体;Ⅱ型斜长石富集轻稀土元素,强烈亏损高场强元素,成分为中长石-倍长石,产于岩体中遭受交代改造较弱的区域,指示它们由熔体结晶形成。据此我们认为"硫化物矿浆"在上侵过程中包含大量流体,应该为"熔体-流体"。文章为流体在硫化物矿浆富集和运移过程中起着重要作用的论点提供了新的证据。The composition and mechanism of intrusion and accumulation of"sulfide slurry"are still under debate in the study of magmatic copper-nickel sulfide deposits.In this report,based on the idea of the newly proposed"magmatic conduit metallogenic system",we studied the ore-bearing olivine-gabbronorite in the Talnakh Cu-Ni sulfide deposit in Norilsk,Russia.We found two types of main rock-forming minerals that have significantly different trace elemental compositions.Here,we focus on the characteristics of plagioclase.Based on the distribution pattern of trace elements,all plagioclase can be divided into two types.The type I plagioclase consists of albite-bytownite and is highly enriched in LILEs and LREEs and largely depleted in HFSEs.It is assembled as sulfide droplet and obviously altered by the fluid,indicating the sulfide droplets are likely filled with fluid.The type II plagioclase is enriched in LREEs,largely depleted in HFSEs,and consists of andesine-bytownite.It shows weak alteration by fluid,suggesting that it is formed by normal crystallization.Thus,we believe that"sulfide slurry"contained a large amount of fluid during the intrusion process and should be called"melt-fluid".This study provides new evidence to support the theory that fluid activities played an important role in the enrichment and migration of sulfides in Cu-Ni sulfide deposits.

关 键 词：塔尔纳赫铜镍硫化物矿床 岩浆通道成矿系统 斜长石 流体活动 

分 类 号：P611.11[天文地球—矿床学] P571[天文地球—地质学]