河北丰宁县大草坪钼矿区岩体锆石U-Pb年龄研究  

Zircon U-Pb ages of intrusive bodies in Dacaoping molybdenum ore district,Fengning County,Hebei Province

作　　者：段焕春[1] 秦正永[2] 林晓辉[2] 张宝华[1] 刘学武[1] 张晓[1] 郭鹏志[1] 韩芳[1] 秦磊[1] 代军治[3] 

机构地区：[1]天津华北地质勘查局,天津300181 [2]国土资源部天津地质矿产研究所,天津300170 [3]中国地质科学院矿产资源研究所,北京100037

出　　处：《矿床地质》2007年第6期634-642,共9页Mineral Deposits

基　　金：天津市国土资源和房屋管理局〔津国土房科(2006)550号〕;天津华北地勘局科技创新项目〔津华勘(2005)210号〕的共同资助

摘　　要：大草坪钼矿属冀北上黄旗构造岩浆岩带钼多金属成矿带,对其赋矿围岩的年龄、矿床成因及类型一直存在争论。通过对岩浆结晶锆石及捕虏晶锆石U-Pb年龄研究,表明大草坪花岗岩岩浆结晶锆石U-Pb年龄为(220.0±1.7)Ma、(224.0±1.5)Ma和(232.7±1.5)Ma,作者据此重新厘定大草坪花岗岩成岩期为印支期,有别于1989年《河北省、北京市、天津市区域地质志》中厘定的燕山期。根据大草坪花岗闪长岩中岩浆结晶锆石U-Pb年龄(134.3±1.2)Ma和(140.0±1.5)Ma,重新厘定大草坪花岗闪长岩成岩期为燕山期,有别于前人厘定的海西期。表明本区含矿岩体来源于古老基底就地多期改造重熔。The Dacaoping molybdenum deposit is located in the molybdenum polymetallic ore-forming belt along the Shanghuangqi tectonic magmatic belt in northern Hebei. There are different viewpoints concerning the age of the ore-bearing rocks as well as the genesis and type of the molybdenum deposit. This paper gives new zircon dating information for wall rocks of the molybdenum deposit. The authors obtained age data of enveloped zircons. The zircon U-Pb ages of （220.0 ± 1.7） Ma and （224.0 ± 1.5） Ma for the granite in Dacaoping suggest the Indosinian period, whereas the zircon U-Pb ages of （134.3 ± 1.2） Ma and （140.0 ± 1.5） Ma for the granodiorite imply the Yanshanian period. The ages are different from those given in Regional Geology of Hebei Province, Beijing and Tianjin. It is thus concluded that the ore-bearing rock body was derived from the old basement and experienced repeated reformation and remelting.

关 键 词：地球化学 锆石U—Pb年龄 成岩年龄 大草坪钼矿床 丰宁 

分 类 号：P618.65[天文地球—矿床学]