中国新生代上地幔铅同位素地球化学场对成岩、成矿物质来源的制约——以斑岩铜矿床及铜镍硫化物矿床为例  

Constraints of the lead isotope geochemical field of the Upper Mantle in China on diagenetic and ore-forming materials exemplified by porphyry copper deposit and copper-nickel sulfide deposit

作　　者：马振东[1] 方俊杰 刘小权 MAZhendong;FANG Junjie;LIU Xiaoquan(China University of Geosciences (Wuhan),Wuhan 430074,Hubei,China)

机构地区：[1]中国地质大学(武汉),湖北武汉430074

出　　处：《中国地质》2019年第1期32-42,共11页Geology in China

基　　金：中国地质调查局项目"中国地球化学场与成矿关系研究"课题(DD20160346)资助~~

摘　　要：区域成矿带铅稳定同位素地球化学研究是区域地球化学分区、示踪成岩成矿物质来源、阐明矿床成因的有效途径。本文以中国特有的大地构造背景为基础,以新生代上地幔铅同位素组成的地球化学场为依据,示踪了中国大型、超大型斑岩型铜矿床及铜镍硫化物型矿床的成岩成矿物质来源。结果显示:①斑岩型铜矿床及铜镍硫化物型矿床成矿母岩继承了所属陆块的上地幔铅同位素组成特征;②两类矿床的含矿岩体和矿石矿物铅同位素组成十分一致,示踪两者同源;壳熔花岗岩和围岩地层的铅同位素组成与矿石铅同位素组成迥异;③位于各陆块的斑岩型铜矿床及铜镍硫化物型矿床的成矿母岩和矿石铅同位素组成除继承了各陆块上地幔不同的铅同位素组成特征外,还示踪了壳幔层圈间耦合性的"块体效应",同时,上地幔铅同位素组成可能还具"延迟效应"。The lead stable isotope geochemistry of regional metallogenic belts is an effective means for making regional geochemical zoning, tracing diagenetic ore-forming sources, and elucidating the genesis of deposits. Based on the unique tectonic setting of China, the authors have traced the diagenesis of large-sized and superlarge porphyry copper deposits and copper-nickel sulfide deposits in China based on the geochemical field of the lead isotope composition of the upper mantle in China for sources of ore-forming materials. Some conclusions have been reached: 1. The porphyry copper deposit and the copper-nickel sulfide type ore- forming parent rock inherit the lead isotope composition of the upper mantle of the adjacent land mass;2. The lead isotope composition of the ore-bearing rock mass and ore minerals of the two types of deposits is obviously consistent with each other, and the two traces are homologous;the lead isotope composition of the shell fused granite and surrounding strata is different from that of the ore;3. In addition to inheriting different lead isotope composition characteristics of the mantle on each land mass, the lead isotope composition of rock and ore in the porphyry copper deposits and the copper-nickel sulfide deposits of each land mass also trace the"block effect"of the coupling between the crust and the mantle layers. At the same time, the lead isotope composition of the upper mantle may exhibits"delay effect".

关 键 词：新生代上地幔铅同位素场 斑岩型铜矿 铜镍硫化物 物质来源 

分 类 号：P594.1[天文地球—地球化学] P618.41[天文地球—地质学]