湖南铜山岭花岗岩体的地球化学特征及锆石SHRIMP定年  

GEOCHEMICAL CHARACTERISTICS AND ZIRCON SHRIMP U-PB DATING OF THE TONGSHANLING GRANITE IN HUNAN PROVINCE,SOUTH CHINA

作　　者：魏道芳[1] 鲍征宇[2] 付建明[3] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]宜昌地质矿产研究所,湖北宜昌443003

出　　处：《大地构造与成矿学》2007年第4期482-489,共8页Geotectonica et Metallogenia

基　　金：中国地质调查局南岭锡矿成矿规律研究项目(200310200072)资助

摘　　要：铜山岭花岗岩具有贫硅、富铁镁钙、弱到中等铕负异常和K2O/Na2O(1的特点,属高钾钙碱性岩石;花岗岩的ISr值(0.71060~0.71124)和εSr(t)值(77.6~81.0)相对较小,δ18O值(8.62‰~9.67‰)较低;TDM年龄(1226~1536Ma)偏小,εNd(t)值(-7.1^-5.2)相对较高;花岗岩中发育壳幔混合的镁铁质微粒包体。这些特征表明该岩体具有壳幔混合花岗岩的性质。岩体SHRIMP锆石U-Pb年龄为149±4Ma,属于燕山中期晚阶段构造岩浆活动的产物。The Tongshanling granite is poor in silicon and rich in iron, magnesium and calcium, belonging to highpotassium calc-alkaline series with weak to intermediate negative Eu anomalies and K20/Na20 〉 1. New SHRIMP zircon U-Pb dating results yield a 23SU/206pb age of 149 ± 4Ma, representing the crystallization age of the intrusion. The Tongshanling granitoids were formed during the stage of Middle Yanshanian tectonomagmatic events. Compared with regional other counterparts, these granitiods have relatively low ISr （0. 71060 - 0. 71124 ）,εSr （t） （ 77.6 - 81.0） and δ^18O （8.62‰～9.67‰） values, spanning eNd（t） and TDM ranges from -7.1 to -5.2 and from 1226 to 1536Ma, respectively. Besides, small mafic inclusions can be found in the granite body. Combined geological observations and geochemical data suggest that the Tongshanling granitoids were derived from a mixture between juvenile mantle-derived materials and the ancient crust.

关 键 词：花岗岩 岩石地球化学 SHRIMP锆石U-PB定年 铜山岭 湖南 

分 类 号：P597[天文地球—地球化学]