摘要
五龙沟金矿位于东昆仑中段,是该区重要的造山型金矿。区内侵入岩非常发育,针对五龙沟金矿红旗沟矿段早志留世二长花岗岩的锆石U-Pb定年和岩石地球化学分析。结果表明该岩体形成年龄为438 Ma±2.8 Ma,岩石地球化学特征显示富硅（68.13%-71.14%）、富碱[w（Na2O＋K2O）=7.81%-8.43%]、富钾（Na2O/K2O=0.70-0.75）,贫Al2O3,Fe2O3,MnO和MgO等特征。稀土总量较高,轻、重稀土分馏及Eu负异常较明显;Rb,Th,K,Pb的相对富集,Sr,P,Ti强烈亏损,暗示其岩浆应起源于成熟度相对较高的中酸性陆壳物质的部分熔融。结合区域上的研究成果,认为该期岩浆活动很可能与早志留世东昆仑洋盆主体关闭和陆壳开始俯冲碰撞有关。
Wulonggou gold deposit is an orogenic-type gold deposit in the middle part of the East Kunlun.Study of zircon U-Pb dating and geochemical analysis on the early Silurian monzagranite in the deposit shows that the emplacement age of monzagranite is 438 Ma±2.8 Ma.Geochemical analysis reveals that the monzagranite has high silicon（68.13%-71.14%）content,alkaline[w（Na2O＋K2O）=7.81% -8.43%],K（Na2O/K2O=0.70-0.75）,low Al2O3,Fe2O3,MnO and MgO contents.It also shows that the monzagranite has high total REE content and the fractionation between light and heavy REE as well as the Eu negative anomaly are obvious.The monzagranite is rich in Rb,Th,K,Pb,strongly depleted in Sr,P,Ti,indicating partial melting of the continental crust with relatively maturity material.Based on the study,combining with regional geological research,it is considered that the early Silurian magmatic and metamorphism activity is likely associated with the closing of the East Kunlun Ocean and the initial collision of continental crust subduction.
出处
《矿物岩石》
CAS
CSCD
北大核心
2016年第2期62-70,共9页
Mineralogy and Petrology
基金
青海省基础应用研究项目(2015-ZJ-762,2016-ZJ-719)
青海省重点实验室发展专项资金计划(2015-Z-Y04)
中国博士后科学基金(2016M592910XB)
关键词
五龙沟
二长花岗岩
早志留世
构造意义
Wulonggou area
monzogranite
early Silurian
geological significance
