内蒙古敖仑花斑岩铜钼矿床花岗岩类地质地球化学特征  

Geochemical Characteristics of the Granitic Rocks in the Aolunhua Porphyre Copper-Molybdenum Deposit,Inner Mongolia

作　　者：邹滔[1,2] 王京彬[2,3] 王玉往[2,3] 袁继明[3] 林龙军[3] 窦金龙[3] 

机构地区：[1]昆明理工大学国土资源工程学院,昆明650093 [2]北京矿产地质研究院,北京100012 [3]有色金属矿产地质调查中心,北京100012

出　　处：《地质学报》2011年第2期213-223,共11页Acta Geologica Sinica

基　　金：国家重点基础研究发展计划"973"项目(编号2007CB411304;2002CB409806)资助成果

摘　　要：敖仑花斑岩铜钼矿床位于大兴安岭南段西拉木伦河断裂北侧,矿床赋存于花岗闪长斑岩岩体及长英质角岩中。矿区脉岩发育,多形成于花岗闪长斑岩体及成矿之后。岩石地球化学表明,赋矿斑岩具有高Si、富Al、Na,低Ca、Mg和Fe2O3T,A/CNK值小于1.1等特征,为偏钠质的高钾钙碱性Ⅰ型花岗岩;稀土元素具微弱负Eu异常,轻重稀土分异比较明显,LREE/HREE值在11.43～18.33,LaN/YbN值在14.64～37.55;岩石具高Sr(>400×10-6),低Y(≤18×10-6)和Yb(≤1.9×10-6),显示出典型的埃达克岩特征。矿区后期的脉岩中,流纹斑岩与赋矿斑岩的地球化学特征差别较大,具有低Sr,高Y和Yb,明显的负Eu异常等特征,反映其构造背景为张性环境;英安斑岩具有弱的负Eu异常,轻重稀土分异度高于流纹斑岩,但略低于花岗闪长斑岩。通过分析矿区花岗岩岩类的地球化学特征及形成构造环境,认为敖仑花铜钼矿床具有有利的成矿条件和很大的找矿潜力。The Aolunhua porphyry copper-molybdenum deposit is located in the north of the Xilamulun flault in the southern area of Da Hinggan Mts.The deposit occurs in the granodiorite-porphyry and felsic hornfels.The dikes in the ore district are very developed and formed later than the granodiorite-porphyry and copper-molybdenum mineralization.Lithogeochemical analysis shows that the host granodiorite-porphyry are rich in Si,Al and Na,poor in Ca,Mg and Fe2O3^T,with A/CNK ratio lower than 1.1,suggesting a type-I granite with high K-Ca-alkili contents.The REE and trace elements of the host granodiorite-porphyry have weak negative Eu anomaly and intensive REE fractionation,with LREE/HREE ratio of 11.43～18.33 and the LaN/YbN ratio of 14.64～37.55.The characteristics of high Sr（400×10^-6）,low Y（≤18×10^-6）and Yb（≤1.9×10^-6）content display that the host granodiorite-porphyry is similar to those of typical adakite.The rhyolite-porphyry characterized by low Sr,high Y and Yb,and obvious negative Eu anomaly,may represents a tensional environment and different structural setting from the host granodiorite-porphyry.The dacite-porphyry is characterized by slight negative Eu anomaly and its fractionation of light and heavy REEs is higher than that of granodiorite-porphyry but lower than that of rhyolite-porphyry.Based on the geochemistry and tectonic setting of the granitic rock in the Aolunhua copper-molybdenum deposit,it is considered that the Aolunhua copper-molybdenum deposit has favorable ore-forming conditions and prospecting potential.

关 键 词：赋矿斑岩 埃达克岩 构造背景 敖仑花铜钼矿 内蒙古 

分 类 号：P618.41[天文地球—矿床学]