内蒙古大井铜多金属矿床脉岩特征及其对成矿的影响

Vein Rock Characteristics and its Influence on Mineralization of Dajing Copper Polymetallic Deposit in Inner Mongolia

内蒙古林西县大井铜多金属矿是大兴安岭地区的重要矿床,成矿元素为铜锡银铅锌.矿区内浅成-超浅成脉岩较多,但未见到大岩体.根据脉岩与矿体的相互关系分析,大井矿床的矿化晚于脉岩的形成.大井矿区的脉岩对矿体具有双重控制作用,脉岩既为矿体就位开辟通道,又阻碍了矿体的延伸.可靠的脉岩年龄数据有6个,分别为162±1Ma、164±1Ma、171±1Ma、239±1Ma、240±1Ma和254±1Ma,表明在矿区内经历了多期岩浆活动,至少包括了印支期、燕山期等两期活动.岩浆活动反映了鄂霍茨克造山运动和华北板块与西伯利亚板块碰撞缝合的构造背景.

The Dajing Cu polymetallic deposit,which is located in Linxi County,Inner Mongolia,is an important deposit in middle-southern Greater Khing’an Range.There is no large rock mass in Dajing mining area,but the ultrahypabyssal vein rock is very developed,which is one of the important characteristics of Dajing mining area.The mineralization of Dajing deposit is later than the formation of vein rock.Vein rocks in Dajing mining area have dual control over orebodies.Dikes not only open up channels for orebodies in place,but also hinder the extension of orebodies.There are six reliable age data of vein rocks,which are 162±1 Ma,164±1 Ma,171±1 Ma,239±1 Ma and 240±1 Ma respectively.It shows that there are at least two magmatic activities in the late Hercynian,Indosinian and Yanshanian periods.It reflects the tectonic background of Mongolia Okhotsk ocean closed collision orogeny,North China plate Siberia plate collision orogeny and late to post orogeny.