松辽盆地林深3井火山岩的锆石U--Pb年龄与Hf同位素组成  

Zircon U——Pb ages and Hf isotopic composition of volcanic rocks from Well Linshen 3 in Songliao Basin

作　　者：金鑫[1] 葛文春[1] 薛云飞[2] 金玉东[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《世界地质》2011年第1期7-17,共11页World Geology

基　　金：国家自然科学基金项目(90814003;40739905)

摘　　要：根据松辽盆地北部林深3井火山岩的岩相、全岩主微量元素、锆石U--Pb同位素和锆石Hf同位素特征的分析结果,探讨了该火山岩的形成时代和岩浆源区。锆石LA--MC--ICPMS U--Pb研究结果表明:林深3井火山岩形成时代约为120 Ma,处于早白垩世中晚期,属于营城组火山岩。锆石的LA--MC--ICPMS Hf同位素研究显示,本区火山岩的锆石εHf(t)全部为较高的正值,二阶段Hf模式年龄为789～1 494 Ma,表明其主要起源于中--新元古代增生的地壳物质,暗示中--新元古代时期兴蒙造山带东段存在地壳增生事件。The formation time and the source rocks of volcanic rocks from Well Linshen 3 in the northern Songliao Basin have been discussed through the petrography,major and trace elements,zircon U——Pb isotopic data and zircon Hf isotopic data of three samples.Zircon U——Pb dating by LA——ICP MS technique indicated that the volcanic rocks from Well Linshen 3 were erupted at ca.120 Ma,the middle——late Early Cretaceous,belonging to of the Yingcheng Formation.Zircon Hf analysis conducted by LA——MC——ICPMS showed that all of the volcanic rocks had high εHf（t）positive values with Hf modal ages of 789~1 494 Ma,indicating the crust in the Songliao Basin extracted from mantle during Meso-and Neoproterozoic,which provides the important evidence of crustal growth during Meso-and Neoproterozoic in eastern Xing——Meng orogenic belt.

关 键 词：松辽盆地 林深3井 火山岩 锆石U--Pb年龄 HF同位素 

分 类 号：P597[天文地球—地球化学]