四川攀西红格矿区辉长岩和正长岩的SHRIMP U-Pb和Sm-Nd定年及其地质意义

发布时间：2018-05-27 01:11

本文选题：攀西红格矿区 + 辉长岩　；参考：《地质通报》2017年05期

【摘要】：用SHRIMP U-Pb和Sm-Nd定年技术,对攀西红格矿区含矿层状辉长岩、碱性正长岩进行了年龄测定。获得红格辉长岩中3种不同晶形锆石的U-Pb年龄分别为258.4±4.1Ma、1841±34Ma、2487±12Ma,由辉长岩、辉石和磷灰石所构成的Sm-Nd等时线年龄为253±14Ma;碱性正长岩中锆石的U-Pb年龄为257.2±1.5Ma。结果表明,红格辉长岩中具有典型基性岩锆石特征的锆石U-Pb年龄(258Ma)与同一地质样品的Sm-Nd年龄(全岩+矿物内部等时线年龄),以及同一矿区的正长岩锆石U-Pb年龄在测定误差范围内一致。鉴于层状辉长岩和碱性正长岩在空间上密切共生,在形成时间上一致,可以认为它们都属于晚二叠世末岩浆活动的产物;而1841Ma和2487Ma的锆石,可能是在基性-超基性岩浆的上侵过程中,从基底所捕获的岩浆锆石和继承锆石,其年龄信息,揭示了康滇地轴岩浆岩带的下部或结晶基底存在元古代甚至新太古代末期的岩石或物质。
[Abstract]:The age of layered gabbro and alkaline syenite in Hongge ore area of Panxi is determined by SHRIMP U-Pb and Sm-Nd dating techniques. The U-Pb age of three kinds of crystalline zircons obtained from Hongge gabbro is 258.4 卤4.1 Mag 1841 卤34MaU 2487 卤12Ma.The Sm-Nd isochron age composed of gabbro, gabbro and apatite is 253 卤14Ma. the U-Pb age of zircon in alkaline syenite is 257.2 卤1.5Ma. The results show that The U-Pb age of zircon with typical basic zircon characteristics in the Hongge gabbro is in agreement with the Sm-Nd age of the same geological sample (isochron age within the whole rock mineral) and the U-Pb age of the syenite zircon from the same ore area within the range of measurement error. Since stratified gabbro and alkaline syenite are closely symbiotic in space and formed at the same time, they can be considered as products of late Permian magmatism, while zircon from 1841Ma and 2487Ma, It may be the age information of magmatic zircon and inherited zircon captured from the basement during the intrusive process of the basic-ultrabasic magma. It is revealed that there are rocks or materials in the lower part or crystalline basement of the magmatic belt of the Kangdian axis of the Proterozoic and even the late NeoArchean.
【作者单位】：中国地质调查局武汉地质调查中心;中国地质科学院矿产资源研究所;四川省地质矿产勘查开发局一0六地质队;
【基金】：中国地质调查局项目《中国矿产地质与区域成矿规律综合研究(中国矿产地质志)》(编号:1212011220369)和《全国重要矿产和区域成矿规律研究》(编号:1212010633903)
【分类号】：P588.12;P597.3

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