大兴安岭塔源金银铜矿区双峰式侵入岩地球化学特征及构造意义  

Geochemical characteristics and tectonic significance of bimodal intrusive rocks in Tayuan Gold Silver Copper District,Greater Khingan Mountains

作　　者：于秋阳 杨言辰[1] 韩世炯[1] 刘宇轩 Yu Qiuyang;Yang Yanchen;Han Shijiong;Liu Yuxuan(College of Earth Sciences,Jilin University)

机构地区：[1]吉林大学地球科学学院

出　　处：《黄金》2022年第4期14-22,共9页Gold

基　　金：中国地质调查局项目(121201103000150060)。

摘　　要：塔源金银铜矿床位于大兴安岭北段,矿区发育双峰式侵入岩(角闪辉长岩、二长花岗岩)。锆石U-Pb定年结果表明,角闪辉长岩成岩年龄为325 Ma±2 Ma、二长花岗岩成岩年龄为324 Ma±3 Ma。元素地球化学测试结果显示,角闪辉长岩属于钙碱性系列,富集轻稀土元素、大离子亲石元素(LILE),亏损高场强元素(HFSE);二长花岗岩属于高钾钙碱性系列,为过铝质岩石,富集轻稀土元素,无明显Eu异常,以明显亏损P、Ti、Nb,富集K和Rb为特征。角闪辉长岩和二长花岗岩在不同源区熔融形成,基性岩源于部分受到陆壳混染的原始地幔,而花岗岩可能来自底侵作用,基性岩浆使其上部地壳发生大规模的部分熔融形成花岗岩。塔源金银铜矿区双峰式侵入岩形成于造山后伸展构造背景下,且兴安地块和松嫩地块最晚于早石炭世末完成碰撞拼合。Tayuan Gold Silver Copper Deposit is located in the north section of Greater Khingan Mountains.Bimodal intrusive rocks(hornblende gabbro and monzogranite)are developed in the mining area.Zircon U-Pb dating results show that the diagenetic age of hornblende gabbro is 325 Ma±2 Ma and that of monzogranite is 324 Ma±3 Ma.The results of element geochemical tests show that hornblende gabbros belong to calc alkaline series,enriched in LREE and large ion lithophile elements(LILE)while depleted in high field strength elements(HFSE);Monzogranite belongs to high-K calc-alkaline series,that is peraluminous rock,enriched in LREE without obvious Eu anomaly.It is characterized by obvious loss of P,Ti and Nb and enrichment of K and Rb.Hornblende gabbro and monzogranite are formed by melting in different homologous areas.The basic rocks are derived from the primitive mantle mixed with continental crust,while the granite may come from underplating.The basic magma causes large-scale partial melting of its upper crust to form granite.The bimodal intrusive rocks in the Tayuan Gold Silver Copper District were formed under the post orogenic extensional tectonic setting,and the collision and amalgamation of the Kingan block and the Songnen block were completed at the end of the Early Carboniferous at the latest.

关 键 词：锆石U-PB定年 构造环境 板块拼合 双峰式侵入岩 塔源金银铜矿区 

分 类 号：TD11[矿业工程—矿山地质测量] P618.51[天文地球—矿床学]