安徽东至兆吉口铅锌矿区岩浆岩锆石U-Pb年龄及其地质意义  

Zircon U-Pb ages of magmatic rocks in Zhaojikou lead-zinc deposits of Dongzhi County,Anhui Province and their geological significance

作　　者：徐晓春[1] 刘雪[1] 张赞赞[2] 何苗[2] 刘晓燕[1] 谢巧勤[1] 范子良[1] 何俊[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009 [2]安徽省地质调查院,合肥230011

出　　处：《地质科学》2014年第2期431-455,共25页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:41172085;40972063);安徽省国土资源厅科技项目(编号:2011-K7)资助

摘　　要：通过对安徽省东至县兆吉口铅锌矿区岩浆岩的LA-ICP MS锆石U-Pb年龄测定,获得矿区北部戴村花岗闪长岩体的年龄为145.5±177;1.3 Ma,花岗斑岩脉的年龄为143.5±177;4.3 Ma,细晶闪长岩脉的年龄为129.0±177;2.3 Ma和128.4±177;2.7 Ma,前两者为同一期岩浆作用的产物,后者为赋矿岩石之一,铅锌矿化与该期岩浆作用关系密切.矿区所有中酸性侵入岩体和岩脉中均发育大量继承锆石,反映有大量成岩物质来源于古老地壳基底.继承锆石核的同位素年龄集中于890～ 740 Ma,揭示出该区晋宁期华夏板块与扬子板块之间的构造—岩浆事件,少量大于1 000 Ma甚至2 500 Ma的锆石年龄数据反映该区可能存在早元古代甚至太古代古老陆壳基底.We report LA-ICP MS zircon U-Pb ages from magmatic rocks of Zhaojikou lead-zinc deposit in Dongzhi County,southern Anhui Province. The zircon U-Pb isotopic ages of Daicun granodiorite and granitic porphyry dyke in the deposit are 145.5±1.3 Ma and 143.5 ± 4.3 Ma,respectively. Moreover, the ages of fine-grain diorite dyke are 129.0±2.3 Ma and 128.4±2.7 Ma. The former are the products of the same period magmatism,the later is one of the ore-bearing rocks and lead-zinc mineralization is closely related to this period magmatism. Many inherited zircons occurred in the intermediate-acid intrusive bodies and dykes of the deposit, which imply numerous diagenetic materials were come from the ancient crustal basement. The isotopic ages of inherited zircon focused on 890-740 Ma reflects the tectonic- magmatic event took place between the Cathaysia plate and the Yangtze plate in the Jinning period. The ages of small amount of zircons in the intrusive rocks are more than 1 500 Ma even 2 500 Ma,which indicates the continental crust in the region has Early Proterozoic or Arehean basement.

关 键 词：MS锆石 U-PB年龄 中酸性岩浆岩 兆吉口铅锌矿床 区域构造演化 

分 类 号：P588[天文地球—岩石学] P597[天文地球—地质学]