青海省祁连县山阴凹槽海相火山岩型锌铜矿床地球化学特征及其成因意义  

Geochemistry and Genetic Significance of the Yin’aocao Marine Facies Volcanic Type Zn-Cu Deposits in Qilian Mountains,Qinghai Province

作　　者：刘青松 袁万明 冯星 时贞 曾小平 王涛 朱小勇 王小龙 

机构地区：[1]中国地质大学(北京)科学研究院,北京100083 [2]山东黄金矿业(莱州)有限公司三山岛金矿,山东莱州261442 [3]青海地质调查局,青海西宁810001

出　　处：《西北地质》2017年第4期105-114,共10页Northwestern Geology

基　　金：国家重点基础研究发展规划项目"吉林省夹皮沟金矿带矿床保存变化与隆升剥露"(2015CB452606);中国地质调查局地质调查工作项目"青海省铜矿主要成矿类型选区研究"(基2011-03-04-06);青海省地质调查局项目"青海省东昆仑东段斑岩型成矿规律研究与找矿靶区优选"(青地调勘2013-103)

摘　　要：祁连县山阴凹槽锌铜矿是中国一个典型的铜多金属成矿区,但总体研究程度较低,目前尚未见到地球化学研究报道。笔者结合矿床地质探讨火山岩主微量元素、稀土元素特征,矿床硫-铅同位素组成与成因。成矿火山岩SiO2(46.96%~53.85%)、TiO2(0.90%~2.02%)质量分数较高,岩石以轻微富集大离子亲石元素(Rb、Ba、K)、相对亏损高场强元素(Nb、Ta、Ti)和Eu轻微正异常、Ce轻微负异常为特征,具有岛弧拉斑玄武岩和N-MORB的双重地球化学特征。火山岩岩浆来源于被俯冲流体交代的亏损地幔,形成环境为弧后盆地扩张环境。锌铜矿化的诸多因素,包括物质来源、容矿围岩和矿液通道等都与火山岩有关,锌矿主要赋存于硅化大理岩中,铜矿主要赋存于大理岩与片理化玄武岩接触带。The Yinaocao ZnCu deposits are an important polymetallogenic area in Qilian Mountains, Qinghai Province. The previous work in this area is less. Combined with basic geological characteristics,the geochemical characteristics of the volcanic rocks and the SPb isotope of this deposit have been studied in this paper. The volcanic rocks from this deposit have high SiO2（6 96%~53 85%） and TiO2（0 90%~2 02%） contents,enriching large ion lithophile elements （Rb,Ba and K）, with relatively loss of high field strength elements（Nb, Ta and Ti）, positive Eu anomaly and negative Ce anomaly characteistics. These geochemical characteristics show the characteristics of and arc tholeiite and N MORB.The volcanic rock magma was derived from the depleted mantle and formed in the extension setting of arc back basin. The zinc and copper mineralization was caused by many geological factors related with volcanic rock, including material source, ore bearing wall rocks and fluid channel. The zinc ore was mainly occurred in silicified maeble, while the copper mineralization was main; y occurred in the contact zone between marble and schistositized basalt.

关 键 词：火山岩型 锌铜矿床 地球化学 成因意义 阴凹槽 祁连山 

分 类 号：P618.41[天文地球—矿床学] P59[天文地球—地质学]