甘肃西秦岭宕昌茹树沟闪长岩岩体单颗粒锆石U-Pb年龄及地质意义  

U-Pb Single Gvain Zircon from Rushugou Diorite,Dangchang,Western Ginling,Gansu Age and Geological Significance

作　　者：徐秀杰 XU Xiu-jie(Gansu Geological Survey Institute Metals,Lanzhou 730030,China)

机构地区：[1]甘肃省有色地质调查院,甘肃兰州730030

出　　处：《甘肃冶金》2020年第1期83-89,共7页Gansu Metallurgy

摘　　要：在1:5万任藏幅区域地质调查中对西秦岭茹树沟岩体进行了调查研究,通过高精度单颗粒锆石U-Pb同位素测年,获得206 Pb-238 U年龄统计权重平均值为212.1±1.5 Ma,属印支晚期。岩体化学和地球化学特征表明,茹树沟岩体属钙碱性系列。在Rb-(Yb-Nb)和Rb-(Yb-Ta)图解中,样品均投在火山弧花岗岩区内,说明在板块碰撞后抬升期,该岩体由下地壳发生部分熔融的岩浆上升形成。岩体稀土元素总量高,轻稀土元素富集,具有较强的负Eu异常,为幔源型花岗岩最明显的特征。The Rushugou intrusion in the western Qinling Mountains was investigated in the regional geological survey of 1:50,000 Ren Tibetan Sheet.Through high-precision single-grain zircon U-Pb isotope dating,the average statistical weight of 206 Pb-238 U age was 212.1+1.5 Ma,which belongs to the late Indosinian period.The chemical and geochemical characteristics of the rock mass indicate that the Rushugou rock mass belongs to calc-alkaline series.In the Rb-(Yb-Nb)and Rb-(Yb-Ta)diagrams,the samples were deposited in the volcanic arc granite area,indicating that during the uplift period after plate collision,the rock mass was formed by the uplift of magma with partial melting in the lower crust.The rock mass is characterized by high total REE content,light REE enrichment and strong negative Eu anomaly,which is the most obvious feature of mantle-derived granite.

关 键 词：西秦岭 茹树沟 单颗粒锆石U-PB年龄 印支晚期 

分 类 号：P595[天文地球—地球化学]