内蒙古东七一山花岗质杂岩的形成演化及对成矿的贡献:年代学及地球化学证据  

Formation,evolution of the granitic complex and its contribution to mineralization in Dongqiyishan deposit,Inner Mongolia:Chronological and geochemical evidences

作　　者：张善明 胡雅璐[4] 王根厚 胡二红[2] 胡华斌 周彦波 何泽宇 ZHANG ShanMing;HU YaLu;WANG GenHou;HU ErHong;HU HuaBin;ZHOU YanBo;HE ZeYu(Mining College,Inner Mongolia University of Technology,Hohhot 010051,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Inner Mongolia Mining Development Co.Ltd.,Hohhot 010011,China;Development Research Center of China Geological Survey,Beijing 100037,China;Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang 050031,China;Hohhot Center of Natural Resources Comprehensive Survey,China Geological Survey,Hohhot 100010,China)

机构地区：[1]内蒙古工业大学矿业学院,呼和浩特010051 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]内蒙古矿业开发有限责任公司,呼和浩特010011 [4]中国地质调查局发展研究中心,北京100037 [5]河北地质大学,河北省战略性关键矿产资源重点实验室,石家庄050031 [6]中国地质调查局呼和浩特自然资源综合调查中心,呼和浩特010000

出　　处：《岩石学报》2023年第6期1791-1816,共26页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2019YFC0605202);国家自然科学基金项目(42202219)联合资助。

摘　　要：内蒙古东七一山钨多金属矿位于北山造山带东段,是一个以钨为主,共伴生锡、钼、铷、铍、铌、钽、铁和萤石的综合型矿床。本次工作对含矿花岗质杂岩开展了岩石学、地球化学、锆石U-Pb及辉钼矿Re-Os年代学研究。富W-Sn-Mo花岗岩岩性为细粒似斑状二长花岗岩、中细粒似斑状二长花岗岩、花岗斑岩,结晶年龄分别为220.6±1.6Ma、220.4±1.3Ma和220.0±1.1Ma。富Rb-Be-Nb-Ta花岗岩岩性为中粗粒钠长石化似斑状二长花岗岩,结晶年龄为219.9±1.9Ma。辉钼矿Re-Os定年获得加权平均年龄为211±1Ma(MSWD=0.83),说明成岩成矿发生在晚三叠世。含矿花岗质杂岩均具有高硅、富碱、贫铁镁钙特征,为高钾钙碱性花岗岩。其中,富W-Sn-Mo花岗岩为准铝质-过铝质花岗岩;而富Rb-Be-Nb-Ta花岗岩为强过铝质花岗岩。杂岩体轻重稀土具一定分馏,呈现显著的负Eu异常,均富集Rb、K、U、Ta,强烈亏损Ba、Nb、Sr、P、Ti、Zr、Hf。与富W-Sn-Mo花岗岩相比,富Rb-Be-Nb-Ta花岗岩具更低的稀土总量,更显著的Eu负异常,并显示微弱的稀土四分组效应,更高的Li、Ta含量,更低的P、Ti、Zr、Hf、W、Mo、Bi含量。时空关系和地球化学特征表明,杂岩体为同一次岩浆活动不同演化阶段的产物,均经历了较高程度的结晶分异和较强的熔体-流体相互作用。相比而言,富Rb-Be-Nb-Ta花岗岩比富W-Sn-Mo花岗岩结晶分异程度更高,熔体-流体作用更强,花岗质岩浆的高程度分离结晶和熔体-流体相互作用是形成该杂岩体并促使成矿的重要控制因素。The Dongqiyishan tungsten polymetallic deposit is located in the eastern Beishan metallogenic belt,which is a large tungsten-dominated deposit associated with tin,molybdenum,rubidium,beryllium,niobium,tantalum,iron and fluorite.We carried out a systematic study of petrology,zircon U-Pb and,geochemistry for the granitic complex and Re-Os dating for the molybdenites.W-Sn-Mo-rich granites are mainly composed of fine-grained to medium-fine grained porphyritic monzonitic granites and granitic porphyry with crystallization ages of 220.6±1.6Ma,220.4±1.3Ma and 220.0±1.1Ma,respectively;while Rb-Be-Nb-Ta-rich granite is mainly medium-coarse grained porphyritic monzonitic granite with a crystallization age of 219.9±1.9Ma.Furthermore,molybdenite Re-Os dating yielded a mean model age of 211±1Ma(MSWD=0.83),indicating that the magmatism and mineralization occurred in Late Triassic.All granites belong to high-K calc-alkaline type,and they are rich in silicon and alkali,and poor in iron,calcium and magnesium.To be more specifically,the W-Sn-Mo-rich granites are quasi-aluminous or peraluminous,while the Rb-Be-Nb-Ta-rich granite is strongly peraluminous.All granites are characterized with enrichment of Rb,K,U and Ta,and strong depletion of Ba,Nb,Sr,P,Ti,Zr and Hf,with extremely negative Eu anomalies and weak fractionation between LREE and HREE.Compared with the W-Sn-Mo-rich granites,the Rb-Be-Nb-Ta-rich granites have lowerΣREE contents,more obvious negative Eu anomalies,and weaker REE four grouping effect;and on the other hand,the Rb-Be-Nb-Ta-rich granite has higher Li and Ta contents,and lower P,Ti,Zr,Hf,W,Mo and Bi contents.The spatial-temporal relationship between these two types of granites together with their geochemical characteristics indicate that the granitic complex are products from a same magmatic activity,and they all have experienced highly fractional crystallization and strong melt-fluid interaction.However,by more detailed comparison,they are formed at different evolution stages,i.e.,the Rb-Be-Nb-Ta-rich grani

关 键 词：锆石U-PB定年 地球化学 辉钼矿RE-OS定年 W-Sn-Mo Rb-Be-Nb-Ta 东七一山 北山 

分 类 号：P618.2[天文地球—矿床学] P587[天文地球—地质学] P597.3