稀有气体同位素对岩浆侵入方向的制约：以夏日哈木镍铜硫化物矿床为例  

The magmatic intrusive direction constrains from noble gas isotopic compositions: A case study of the Xiarihamu Ni-Cu sulfide deposit in East Kunlun orogenic belt,China

作　　者：王小东 张铭杰 伏珏蓉 张江伟[2] 李立武[3] 汤庆艳 李中平[3] WANG XiaoDong;ZHANG MingJie;FU JueRong;ZHANG JiangWei;LI LiWu;TANG QingYan;LI ZhongPing(Gansu Key Lab of Mineral Resources in Western China,School of Earth Sciences,Lanzhou University,Lanzhou 730000,China;MLR Key Lab of Geneis and Exploration of Magmatic Ore Deposits,Xi＇an Center of Geological Survey,CGS,Xi＇an 710054,China;Gansu Key Lab of Petroleum Resource Research,Institute of Geology and Geophysics,CAS,Lanzhou 730000,China)

机构地区：[1]兰州大学地质科学与矿产资源学院,甘肃省西部矿产资源重点实验室,兰州730000 [2]中国地质调查局西安地质调查中心,国土资源部岩浆作用成矿与找矿重点实验室,西安710054 [3]中国科学院地质与地球物理研究所,甘肃省油气资源研究重点实验室,兰州730000

出　　处：《岩石学报》2018年第11期3433-3444,共12页Acta Petrologica Sinica

基　　金：国土资源部公益性行业科研专项(201511020); 国家自然科学基金项目(41472070、41372095); 陕西省自然科学基础研究计划(2017JM4002); 高等学校博士学科点专项科研基金项目(20120211110023); 甘肃省西部矿产资源重点实验室开放基金(WCRMGS-2014-04); 中国地质调查局项目(12120114044401)联合资助

摘　　要：我国东昆仑造山带新发现的夏日哈木镍铜硫化物矿床是造山带环境产出全球镍资源最大的岩浆镍铜矿床。含矿岩体不同类型岩石中橄榄石和辉石的He、Ne和Ar同位素组成表明:~3He/~4He(0.39~0.03Ra)和^(40)Ar/^(36)Ar比值(292.0~316.9)较低,^(20)Ne/^(22)Ne和^(21)Ne/^(22)Ne沿放射性成因Ne及大陆地壳线分布,表明岩浆起源演化过程中有大陆地壳组分和大气饱和流体在橄榄石结晶前加入。He和Ar同位素混合模型计算表明岩浆中有7.8%再循环洋壳组分和87.7%大气饱和流体的加入,再循环洋壳可能带入了大气及地壳组分。~3He/~4He和^(40)Ar/^(36)Ar比值的自西向东系统性降低,以及微量元素、成矿元素和稀有气体同位素的空间协同变化特征表明地壳物质的逐步加入,即岩浆可能自西向东方向侵入,侵位过程中地壳流体的加入促使硫饱和及硫化物的熔离成矿。The newly discovered Xiarihamu magmatic Ni-Cu sulfide deposit in the East Kunlun orogenic belt,western China is the largest one formed in orogenic belt settings.The He,Ne and Ar isotopic compositions from olivine and pyroxene separates of different types of rocks in the Xiarihamu Ni-Cu sulfide deposit have low^3He/~4He（0.39~0.03）and^（40）Ar/^（36）Ar（292.0~316.9）ratios,with their^（20）Ne/^（22）Ne and^（21）Ne/^（22）Ne ratios distributed along the line of continental crust evolution,indicating that there are some components of continental crust and air saturated fluid（ASF）added into the ore-forming magma before olivine crystallization in the process of the magma evolution.He and Ar isotope mixing model calculations show that 7.8%recycled oceanic crust and 87.7%ASF are added into the magma.The recycled oceanic crustal materials and saturated air fluid might be brought and added into the magmatic sources by the subducted plate.The spatial variation of^3He/~4He and^（40）Ar/^（36）Ar ratios as well as Ni and Cu contents from west to east part of intrusion suggested that crustal materials were added progressively,i.e.,the magma intrusion direction was from west to east.The addition of crustal fluids into the magma during the intruding process results in the sulfur saturation and segregation of sulfide in silicate melt.

关 键 词：岩浆侵位方向 稀有气体同位素 超镁铁质岩 镍铜硫化物矿床 夏日哈木 

分 类 号：P597[天文地球—地球化学] P611[天文地球—地质学]