青海牛鼻子梁铜镍硫化物矿床含矿岩体锆石U-Pb年代学及其成矿意义  

Zircon U-Pb Chronology and Metallogenic Significance of the Ore-bearing Rock Body of the Niubiliang Copper-Ni Sulfide Deposit in Qinghai

作　　者：周自强 尹晨曦 赵少卿[1] 孟庆昊 陆相吉 张炎 张乐乐 ZHOU Ziqiang;YIN Chenxi;ZHAO Shaoqing;MENG Qinghao;LU Xiangji;ZHANG Yan;ZHANG Lele(School of Geosciences,Yangtze University)

机构地区：[1]长江大学地球科学学院,湖北省武汉市430100

出　　处：《现代矿业》2021年第4期13-19,28,共8页Modern Mining

基　　金：长江大学大学生创新创业训练计划项目(编号:2018027,2019028),长江大学长江青年基金项目(编号:2016cqn0)。

摘　　要：牛鼻子梁铜镍硫化物矿床位于柴达木盆地西北缘、阿尔金构造—岩浆岩带南侧,是柴周缘地区新发现的造山带背景重要岩浆铜镍硫化物矿床之一。矿区出露3个镁铁—超镁铁质岩体,其中二辉橄榄岩为主要含矿岩石。选取镁铁—超镁铁质岩体中的含矿二辉橄榄岩作为研究对象,采用LA-ICP-MS锆石U-Pb定年的方法进行了测试分析,探讨了成岩年代学及其成矿意义。定年结果表明牛鼻子梁镁铁—超镁铁质含矿岩体的侵位年龄为400±2 Ma(MSWD=0.4),为早泥盆世晚期。结合区内其它岩浆岩研究成果,对比分析表明,牛鼻子梁含矿镁铁—超镁铁质岩体可能形成于造山带碰撞后伸展背景,且柴周缘地区超大型和一系列中小型铜镍矿床的发现,暗示早古生代末期可能是我国第三大Cu-Ni-PGE成矿事件。Niubiziliang Cu-Ni sulfide deposit is located in the northwest margin of Qaidam Basin and the south side of Altun tectonic-magmatic belt.It is one of the important magmatic Cu-Ni sulfide deposits in the orogenic belt.There are three mafic-ultramafic rocks in the mining area,in which diopside is the main ore-bearing rock.The ore-bearing diabase in mafic-ultramafic rock mass was selected as the research object.LA-ICP-MS zircon U-Pb dating method was used to test and analyze the diagenetic chronology and its metallogenic significance.The dating results show that the emplacement age of Niubiziliang mafic-ultramaf⁃ic ore-bearing rock mass is 400±2 Ma(MSWD=0.4),which is the late Early Devonian.Combined with the research results of other magmatic rocks in the area,the comparative analysis shows that the ore-bearing mafic-ultramafic intrusion in Niubiziliang may be formed in the post-collisional extension background of orogenic belt,and the discovery of superlarge and a series of small and medium sized copper-nickel depos⁃its in the periphery of Qaidam suggests that the late Early Paleozoic may be the third largest Cu-Ni-PGE metallogenic event in China.

关 键 词：镁铁—超镁铁质岩 锆石U-PB年代学 铜镍硫化物矿床 牛鼻子梁 阿尔金构造带 

分 类 号：P618.2[天文地球—矿床学]