东天山百灵山岩体花岗闪长岩锆石U-Pb年龄、地球化学特征及地质意义

摘要

There are series of granitic rock which distribute within the Joltag orogenic belt east-west extension,Hongyuntan rock body,Tieling rock body,Bailingshan rock body and Luotuofeng rock body respectively distributed from the west to the east,constitute a multiphase rock mass,The study of the major content element shows that the granodiorite of Bailingshan rock body is a series of calc-alkaline rocks with high silicon,high potassium and low titanium,and the continental arcs of aluminum.Trace elements show the cognate magma evolution,rare earth content is higher,light and heavy rare earth differentiation obvious,light rare earth concentration,heavy rare earth losses,and have obvious Eu negative anomaly,has the basic characteristics of island arc granite.The LA-ICP-MS zircon U-Pb age is(309+2.3)Ma,which is of good harmony and high reliability,indicating that the pericartic rock mass is a late carboniferous intrusive rock.Tectonics research shows that the volcanic arcs formed at the end of the late carboniferous period are the products of the melting of the shell mantle.%觉罗塔格构造带内分布一系列EW向延伸的花岗质岩体,自西向东分别为红云滩岩体、铁岭岩体、百灵山岩体、骆驼峰岩体等,构成一个多期次侵入的复合岩体.主量元素研究表明,百灵山岩体花岗闪长岩为高硅、高钾、低钛的钙碱性岩石系列,为准铝质大陆弧花岗岩类.痕量元素为同源岩浆演化生成,稀土含量较高,轻重稀土分异明显,轻稀土富集,重稀土亏损,具明显的Eu负异常及岛弧花岗岩基本特征.LA-ICP-MS锆石U-Pb年龄为(309±2.3)Ma,谐和度好,可信度高,说明百灵山岩体为晚石炭世侵入岩.研究表明,百灵山岩体花岗闪长岩形成于晚石炭世末期康古尔洋俯冲下的火山弧环境,为壳幔混融产物.