中亚成矿域Erdenet斑岩型铜钼矿床和Oyu Tolgoi斑岩型铜金矿床对比  

Comparison Between Erdenet Porphyry Cu-Mo and Oyu Tolgoi Porphyry Cu-Au Deposits in the Central Asian Metallogenic Domain

作　　者：李润武 童英[2] 苏尚国[1] LI Run-wu;TONG Ying;SU Shang-guo(School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Beijing SHRIMP Center,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质科学院地质研究所北京离子探针中心,北京100037

出　　处：《地球科学与环境学报》2021年第3期506-527,共22页Journal of Earth Sciences and Environment

基　　金：国家重点研发计划项目(2018YFC0603702);中国地质调查局地质调查项目(DD20160123,DD20190685);国际地球科学计划项目(IGCP662)。

摘　　要：中亚成矿域位于北侧西伯利亚克拉通、南侧华北—塔里木克拉通及西侧东欧克拉通之间,与环太平洋成矿域和特提斯成矿域并称为全球三大成矿域,发育有一系列大型—超大型斑岩型铜金、斑岩型铜(金、钼)及斑岩型铜钼矿床。对比研究了中亚成矿域两个典型斑岩型矿床——Erdenet斑岩型铜钼矿床与Oyu Tolgoi斑岩型铜金矿床的矿床地质特征和与成矿相关的岩石地球化学特征异同。结果表明:Erdenet斑岩型铜钼矿床成矿斑岩岩性主要是花岗岩和花岗闪长岩,同时代发育的火山岩主要是安山岩、英安岩和流纹岩,属于钙碱性—高钾钙碱性系列;Oyu Tolgoi斑岩型铜金矿床成矿斑岩则主要是石英二长闪长岩,矿化后期的花岗闪长斑岩仅发育有弱矿化作用,同时代火山岩以英安质-玄武质岩石为主,主要属于高钾钙碱性系列。这两个矿床与成矿相关的岩石微量和稀土元素配分特征相似,均显示弧岩浆岩地球化学特征,但Erdenet斑岩型铜钼矿床显示出高Sr/Y和La/Yb值及低相容元素(Cr、Ni)含量,且与Oyu Tolgoi斑岩型铜金矿床相比,Erdenet斑岩型铜钼矿床具有相对富集的Sr-Nd-Hf同位素组成。结合区域地质背景资料认为:Erdenet斑岩型铜钼矿床成矿斑岩源于加厚新生下地壳物质的部分熔融作用,形成于蒙古—鄂霍茨克洋西段演化末期的陆缘弧环境;而Oyu Tolgoi斑岩型铜金矿床成矿斑岩源于亏损地幔物质的分离结晶作用,形成于与古亚洲洋北向俯冲有关的大洋岛弧环境;不同的构造背景形成了这两类具不同特征的斑岩型矿床。The Central Asian metallogenic domain(CAMD)is located between the Siberian craton to the north,the North China-Tarim craton to the south,and the East Europe craton to the west.It s considered as one of the three major metallogenic domains in the world along with the Circum-Pacific and the Tethyan metallogenic domains.There exists a series of porphyry Cu-Au,Cu(Au,Mo)and Cu-Mo deposits,and the two representative deposits from them,namely Erdenet porphyry Cu-Mo and Oyu Tolgoi porphyry Cu-Au deposit,were chosen to make comprehensive comparisons in terms of geological characteristics and ore-related rocks geochemical features.Mineralizing porphyrys of Erdenet porphyry Cu-Mo deposit are mainly granites and granodiorites,and the volcanic rocks developing in the same period are primarily andesite,dacite and rhyolite,all of which show calc-alkaline to high-K calc-alkaline series rocks.Mineralizing porphyrys of Oyu Tolgoi porphyry Cu-Au deposit are mainly quartz monzodiorites,and the same period s volcanic rocks primarily consist of dacite-basaltic rocks,belonging to high K calc-alkaline series.The trace and rare earth elements of the ore-related rocks from the above two deposits show typical features of arc magmatic rocks.However,compared with Oyu Tolgoi porphyry Cu-Au deposit,Erdenet porphyry Cu-Mo deposit shows high Sr/Y and La/Yb ratios,low contents of compatible elements(Cr,Ni)and relatively enriched Sr-Nd-Hf isotopic compositions.Combined with the regional geological background of the study area,it is believed that the mineralizing porphyrys of Erdenet porphyry Cu-Mo deposit originate from the partial melting of the thickened young lower crustal material,and are formed in a continental arc tectonic setting during the end of the Mongol-Okhotsk ocean evolution,while Oyu Tolgoi porphyry Cu-Au deposit s mineralizing porphyrys generate from fractional crystallization of depleted mantle materials,and form in an island arc tectonic setting.Therefore,it can be concluded that Erdenet porphyry Cu-Mo and Oyu Tolgoi porphyry Cu-

关 键 词：成矿规律 斑岩型矿床 成矿斑岩 地质特征 地球化学 岩石成因 构造环境 中亚成矿域 

分 类 号：P612[天文地球—矿床学]