内蒙古下陶勒盖铁铜矿床成矿岩体地球化学特征及其成岩成矿启示  

Geochemical Characteristics of Ore-forming Intrusions and their Diagenetic and Metallogenic Revelation from the Xiataolegai Iron and Copper Deposit,Inner Mongolia

作　　者：宋彦博 王继春[2] 袁硕浦 王建平[1] 翟德高[1] 柳振江[1] 许展[2] 王东星[2] 邱广东[2] 杨永亮 SONG Yanbo;WANG Jichun;YUAN Shuopu;WANG Jianping;ZHAI Degao;LIU Zhenjiang;XU Zhan;WANG Dongxing;QIU Guangdong;YANG Yongliang(School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Autonomous Region Geological Survey Institute of Inner Mongolia,Hohhot 010020,Inner Mongolia,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]内蒙古自治区地质调查院,内蒙古呼和浩特010020

出　　处：《西北地质》2024年第2期90-106,共17页Northwestern Geology

基　　金：内蒙古自治区自然资源厅项目“内蒙古北山成矿带黑鹰山–石板井地区铁铜钼多金属成矿系统研究与找矿预测”(2022-TZH03)资助。

摘　　要：下陶勒盖铁铜矿床是位于内蒙古阿拉善盟额济纳旗西部的一处矽卡岩铁铜矿床,同时也是北山成矿带旱山地块古生代活动陆缘矽卡岩成矿系统的典型代表。其成矿与花岗闪长岩和二长花岗岩有密切的时空联系,为查明二者的形成时代、岩浆源区特征及其与矿化之间的关系,笔者开展了对花岗闪长岩和二长花岗岩进行了岩相学、岩石地球化学及锆石U-Pb年代学研究。结果表明,花岗闪长岩与二长花岗岩均具高SiO_(2)、Al_(2)O_(3)含量和高碱含量,低MgO含量,轻稀土元素富集,重稀土元素亏损。花岗闪长岩具Eu负异常和弱Ce正异常,亏损Ta、Nb、Ti和P等高场强元素,富集Rb和La等大离子亲石元素;二长花岗岩具弱Eu负异常和Ce正异常,亏损Nb、Ti和P等高场强元素,富集Rb和U等大离子亲石元素,这些特征表明二者均属钙碱性I型花岗岩。获得花岗闪长与二长花岗岩锆石U-Pb年龄分别为(451.7±4.8)Ma和(460.1±4.9)Ma,指示该矿床东矿段和西矿段成岩及与其相关的成矿作用分别发生于晚奥陶世和中奥陶世。综合分析认为,下陶勒盖铁铜矿床形成于中—晚奥陶世陆缘弧构造环境,与洋盆俯冲产生的挤压作用有关。The Xiataolegai iron and copper deposit,located in Inner Mongolia,is a representative skarn-type deposit within the active continental margin of the Beishan Metallogenic Belt.Situated in the western part of the Ejina Banner in the Alashan League,it is closely associated in both time and space with granodiorite and monzogranite linked to Fe-Cu mineralization.To ascertain the formation age,source characteristics,and the relationship between magmatism and mineralization,samples underwent petrography,geochemical analysis,and zircon U-Pb dating.Results reveal high SiO_(2),Al_(2)O_(3),alkalinity,and low MgO,with LREE enrichment and HREE depletion in both granodiorite and monzogranite.Granodiorite exhibits Rb,La enrichment,Ta,Nb,Ti,P depletion,weak Ce positive and Eu negative anomaly,while monzogranite shows Rb,U enrichment,Nb,Ti,P depletion,Ce positive and weak Eu negative anomaly Both granodiorite and monzogranite are classified as calc-alkaline Itype granite.The obtained U-Pb ages for zircons from granodiorite and monzogranite are(451.7±4.8)Ma and(460.1±4.9)Ma,indicating that the magmatism and related mineralization in the eastern and western section of the deposit occurred in the Late Ordovician and Middle Ordovician,respectively.A comprehensive analysis suggests that the Xiataolegai deposit formed in the late-middle Ordovician within an active continental margin arc tectonic setting,likely associated with oceanic plate subduction.

关 键 词：下陶勒盖铁铜矿床 花岗闪长岩 二长花岗岩 岩石地球化学 锆石U-PB定年 

分 类 号：P595[天文地球—地球化学] P618.41[天文地球—地质学]