青海加当根斑岩型铜(钼)矿床岩石地球化学特征及其成因认识  

Geochemistry and Genesis of Igneous Rocks in Jiadanggen Porphyry Cu(Mo) Deposit, Qinghai Province, China

作　　者：向鹏[1,2] 姚书振[1] 周宗桂[1] 

机构地区：[1]中国地质大学资源学院,湖北武汉430074 [2]中国地质调查局武汉地调中心,湖北武汉430205

出　　处：《西北地质》2013年第1期139-153,共15页Northwestern Geology

基　　金：青海省都兰-鄂拉山地区成矿条件及找矿方向研究(2008026362)

摘　　要：青海加当根斑岩型铜(钼)矿床位于东昆仑造山带,祁漫塔格-都兰造山亚带的东端,是近年来新发现的矿床,目前该矿床的研究程度较低。对矿区火成岩样品全岩地球化学测试结果表明,矿区含矿斑岩岩具有富硅、碱,贫钛、钙、镁,过铝质的特征,岩石系列属于高钾钙碱性系列。稀土元素上,总体表现为轻稀土富集型,具有Eu负异常。微量元素上,K、Rb、Ba等元素明显富集,Ta、Nb、Zr、Hf、等相对富集,P、Ti、Y、Yb等明显亏损,且不具有埃达克岩亲和性,微量和稀土元素特征反映出产于陆缘弧的环境。结合区域地质背景、岩石地球化学特征及判别图解,认为加当根矿区火成岩产于碰撞造山初期,陆缘弧与碰撞造山并存的环境,其成因起源于残留洋壳的脱水作用使地幔楔发生部分熔融。The Jiadanggen porphyry Cu （Mo） deposit lies in the east of Qimantage-Dulan suborogen, East Kunlun orogen, Qinghai Province. It is a newly discovered mineral deposit in recent years, and with low degree in studying. The geochemistry analysis on igneous rock samples in the Jiadanggen mining area shows that the ore bearing porphyry are characterized by high SiOz, alkali, low TiO2, CaO, and MgO, which is high-potassium cale-alkaline series. The REE are characterized by LREE enrichment, with obvious negative Eu anomalies. The trace elements are characterized by K, Rb, Ba, etc enrichment obviously; Ta, Nb, Zr, Hf, ere enrichment relatively; P, Ti, Y, Yb, etc depletion obviously. The characteristics of the REE and trace elements indicated the continental margin arc tectonic setting. Combining regional geology background and geochemistry of the igneous rocks in Jiadanggen deposit, the Jiadanggen igneous rocks may be formed in the early stage of the collision orogeny, continental margin arc and collision orogeny coexistence environment. And it was formed from dehydration of residual oceanic crust which caused mantle wedge partial melting.

关 键 词：鄂拉山地区 斑岩铜矿 岩石地球化学 构造背景 

分 类 号：P59[天文地球—地球化学]