秦岭富水杂岩的变辉长岩中斜锆石与锆石U-Pb同位素年龄的差异及其地质意义  

Age Difference between Baddeleyite and Zircon from Metagabbro in Fushui Complex of the Qinling Mountains and Its Geological Implications

作　　者：李惠民[1] 相振群[1] 李怀坤[1] 陆松年[1] 陈志宏[1] 周红英[1] 宋彪[2] 

机构地区：[1]中国地质调查局天津地质矿产研究所,天津300170 [2]中国地质科学院地质研究所、北京离子探针中心,北京100037

出　　处：《地球学报》2005年第B09期57-60,共4页Acta Geoscientica Sinica

基　　金：本文由国家自然科学基金重点项目（编号：40032010-C）和国家自然科学基金项目（批准号：40373032）资助.

摘　　要：秦岭富水杂岩体的一些变辉长岩含有粒度较大，U、Pb含量较高的斜锆石和锆石，是U—Pb同位素测年的极好矿物。本文对秦岭富水杂岩的中粗粒角闪黑云辉长岩中的斜锆石和锆石分别进行了SHRIMP法和TIMS法U—Pb同位素年龄测定，获得斜锆石和锆石的UPb同位素年龄分别为501．4±1．2Ma和480．0±3．4Ma，二者相差约20Ma；对该岩石中的斜锆石和锆石的关系及锆石的成因进行了初步研究，认为斜锆石的UPb同位素年龄应可解释为秦岭富水杂岩中基性岩石的形成时代，而锆石的成因比较复杂，对其U—Pb同位素年龄地质意义的合理解释需作进一步的研究。There are baddeleyites and zircons with high U and Pb in metagabbro from Fushui complex in the Qinling Mountains. They are very ideal minerals for U-Pb isotope dating. The baddeleyites and zircons were dated by SHRIMP and TIMS U-Pb dating methods. Age data of 501.4 ± 1.2 Ma for baddeleyites and 480.0 ± 3.4 Ma for zircons were obtained. The age difference between baddeleyite and zircon is about 20 Ma. The baddeleyite-zircon relationship in the metagabbro and the zircon genesis were studied. The Baddeleyite age of 501.4 ± 1.2 Ma is interpreted as the formation age of the metagabbro in Fushui Complex of the Qirding Mountains. As the genesis of the zircon is very complex, the reasonable interpretation for the zircon age of 480.0 ± 3.4 Ma requires further studies.

关 键 词：秦岭富水杂岩 辉长岩 斜锆石 锆石 U—Pb同位素年龄 锆石U-PB同位素年龄 富水杂岩体 地质意义 秦岭 同位素年龄测定 

分 类 号：P588.122[天文地球—岩石学] P583[天文地球—地质学]