云南格咱岛弧岩浆成矿带铅同位素特征及成矿物质来源示踪  

Lead Isotope Characteristics and Tracing Significance of Ore Metallogenic Material in Geza Arc Metallogenic Belt,Yunnan

作　　者：刘学龙[1,2] 李文昌[1,2] 尹光侯 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]云南省地质调查局,云南昆明650051

出　　处：《现代地质》2012年第3期445-452,共8页Geoscience

基　　金：国家重点基础研究发展计划项目("973"课题)"巨型矿床的变化与保存"(2009CB421007);中央高校基本科研业务费专项资金项目"云南中甸格咱岛弧斑岩成矿系统研究"(2011PY0154);中国地质调查局国土资源大调查项目"滇西北地区斑岩成矿系统研究与靶区优选"

摘　　要：云南格咱岛弧成矿带是西南三江构造岩浆岩带的重要组成部分,是我国近年来新发现的铜多金属矿集区,产出有普朗超大型斑岩型铜矿、雪鸡坪中型斑岩型铜矿、红山大型矽卡岩-斑岩型铜矿等。测试结果表明,典型成矿斑岩体的矿石矿物铅同位素组成:206Pb/204Pb为17.680～19.165,207Pb/204Pb为15.453～15.773,208Pb/204Pb为37.730～39.654,铅同位素组成较为稳定,具有贫铀铅、富钍铅的特征。铅同位素组成与特征参数(Δβ与Δγ、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,格咱岛弧成矿带的铅主要来源于地幔和下地壳,具壳幔混合来源的特征,其成矿作用与岩浆岩活动存在较为密切的关系。Geza arc is an important part of Yidun island arc in the southwest Sanjiang tectonic magmatic belts, located in the southern tip of the Yidun island arc, newly discovered copper polymetallic ore concentration area of China in recent years, in which Pulang super-large-sized porphyry copper deposits, Xuejiping medium-sized porphyry copper deposits, Hongshan large-sized skarn-porphyry copper deposits occur. The lead isotopic com- positions of ore mineral, with ^206Pb/^204Pb ranging from 17. 680 to 19. 165,^207Pb/^204Pb ranging from 15. 453 to 15. 773,^208Pb/^204pb ranging from 37. 730 to 39. 654, was relatively stable and charactered by depleted urani- um, rich thorium. There was a significant positive correlation between lead isotopic composition and characteris- tic parameters （△β and △γ, V1 and V2）. Based on the lead structural pattern recognition and the original clas- sification of comprehensive analysis, the lead isotope of Geza island arc metallogenic belt is mainly derived from the mantle and the lower crust, with the crust-mantle mixed source characteristics. The mineralization is closely related with magmatic activities.

关 键 词：岛弧成矿带 铅同位素 成矿物质来源 格咱 云南 

分 类 号：P618.4[天文地球—矿床学]