云南格咱岛弧带南缘铜厂沟斑岩型铜钼矿床硫铅同位素特征与成矿物质来源示踪  

Characteristics of sulfur and lead isotopes and tracing of mineral sources in the Tongchanggou porphyry Mo(Cu) deposit at the southern edge of Geza arc belt,Yunnan

作　　者：刘学龙[1] 李文昌[1,2] 张娜[1] 杨富成[1] 康健[1] 张彪[1] 

机构地区：[1]昆明理工大学,云南昆明650093 [2]云南省地质调查局,云南昆明650051

出　　处：《中国地质》2016年第1期209-220,共12页Geology in China

基　　金：中国地质调查局项目(12120114013701);中国博士后科学基金项目(2014M552547XB);昆明理工大学省级人培项目(KKSY201421042)联合资助~~

摘　　要：铜厂沟斑岩型铜钼矿床位于格咱岛弧成矿带南缘,是西南三江地区近年来新发现的大型斑岩型铜钼多金属矿床。本文通过硫、铅同位素的示踪研究,探讨了成矿物质的来源。测试结果表明,矿石中硫化物的δ34S值变化于-0.7‰^+3.8‰,平均为0.79‰,变化范围很小,表明硫同位素来源单一,显示岩浆源硫同位素组成的特征。矿石矿物的铅同位素组成,206Pb/204Pb为18.3325~18.694,207Pb/204Pb为15.588~15.663,208Pb/204Pb为38.454~39.008,铅同位素组成较为稳定,显示正常铅的特征。铅同位素组成与特征参数(△β与△γ、V1与V2)之间具有明显的正相关性,依据铅构造模式判别和成因分类的综合分析,铜厂沟斑岩型铜钼矿床的铅主要来源于深部,并显示壳幔混合来源的特征。矿床的成矿作用与燕山期岩浆侵入岩活动存在较密切的关系,但地层源的成矿物质对矿床的形成有一定的物质贡献。Located on the southern margin of the Geza island arc, the Tongchanggou porphyry deposit is a large- sized Mo（Cu）polymetallic deposit discovered in recent years in southwest Sanjiang region. In this paper, the authors investigated the sources of minerals through sulfur and lead isotope tracer study. Testing results show that the δ^34S values of ore sulfides vary in the range of-0.7‰—＋3.8‰, 0.79‰ on average. The variation range is very small, which indicates a single source of the sulfur isotope and displays the characteristics of magmatic source sulfur isotopic composition. The lead isotopic composition of ore minerals is characterized by^206Pb/^204 Pb ranging from 18.3325 to 18.694,^207Pb/^204 Pb ranging from 15.588 to 15.663, and^208Pb/^204 Pb ranging from38.454 to 39.008, exhibiting relatively stable Pb isotopic composition and showing the normal lead characteristics. There is a significant positive correlation between lead isotopic composition and characteristic parameters（ △ β and △ γ, V1 and V2）. Lead structural model identification and genetic classification comprehensive analysis suggest that the lead isotopes of the Tongchanggou porphyry Mo（Cu） deposit were mainly derived from the depth and show the crust- mantle mixed source characteristics. The mineralization had a close relationship with Yanshanian magmatic intrusion, with the minerals of the strata also making some contribution.

关 键 词：斑岩型铜钼矿床 硫同位素 铅同位素 成矿物质来源 铜厂沟 格咱岛弧南缘 

分 类 号：P618.41[天文地球—矿床学] P618.65[天文地球—地质学]