铜陵地区铜官山矿田侵入岩锆石SHRIMP定年  

Zircon SHRIMP Dating of Intrusive Rocks from the Tongguashan Ore-Field in Tongling,Anhui,China

作　　者：吴才来[1] 高前明 国和平 郭祥炎 刘良根[2] 郜源红[1] 雷敏[1] 秦海鹏[1] 陈其龙[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]安徽省地矿局321地质队,安徽铜陵244033

出　　处：《地质学报》2010年第12期1746-1758,共13页Acta Geologica Sinica

基　　金：国家专项(编号SinoProbe-05-05);创新研究群体科学基金项目(编号40921001);国家自然科学基金项目(编号49772106;40472034和40672049);中国地质调查局项目(编号1212010918007;1212010818090;1212010611803和1212010711816)共同资助成果

摘　　要：铜陵铜官山矿田的中酸性侵入岩属高钾钙碱性系列,主要岩石类型为石英二长闪长岩和花岗闪长岩。本文对该矿田内的铜官山岩体和天鹅抱蛋岩体进行了锆石的SHRIMPU-Pb定年。结果表明,铜官山和天鹅抱蛋石英二长闪长岩的锆石SHRIMPU-Pb年龄几乎相同,分别为141.8±1.0Ma和141.3±1.3Ma,反映它们是同一次岩浆侵入作用的产物。结合锆石CL分析得出,两岩体中均含有新太古代、古元古代和新元古代岩浆型的继承性锆石核,说明本区岩浆的源岩含有古老的下地壳成分,锆石微量及稀土元素特征也表明其为陆壳而非洋壳成因,结合同位素和包体特征,得出岩浆来自富集地幔并含有古老地壳成分。The Mesozoic intermediate-acid intrusive rocks in the Tongguashan ore -field belong to the high-potassium （K） calc-alkaline series with main rock t ypes of quartz monzodiorite ＋ granodiorite. Zircon SHRIMP U-Pb dating of Tonggu anshan and Tian＇ebaodan bodies shows that both have almost the same age,being 141.8±1.0 Ma for Tongguanshan and 141.3±1.3 Ma for the Tebodan body,respectiv ely,indicating they are the product of the same magmatism. Zircon cathodolumine scence （CL） analysis also shows that both intrusive bodies all contain ancient m agmatic inherited zircon cores with the times of Neoarchean,Paleoproterozoic an d Neoproterozoic,which were derived from the continental crust not from oceanic crust based on the trace and rare earth elements of the zircons. On the basis o f the previous studies on isotope of the intrusive rocks and enclave petrology i n the rock bodies,it can be concluded that the magma was derived from enriched mantle with some ancient continental materials.

关 键 词：锆石SHRIMP定年 锆石稀土微量元素 侵入岩 铜官山矿田 安徽铜陵 

分 类 号：P597.3[天文地球—地球化学]