首页 | 本学科首页   官方微博 | 高级检索  
     检索      

北秦岭马河钼矿区花岗岩类的锆石U-Pb年龄、地球化学特征及其地质意义
引用本文:柯昌辉,王晓霞,李金宝,齐秋菊.北秦岭马河钼矿区花岗岩类的锆石U-Pb年龄、地球化学特征及其地质意义[J].岩石学报,2012,28(1):267-278.
作者姓名:柯昌辉  王晓霞  李金宝  齐秋菊
作者单位:1. 中国地质科学院矿产资源研究所,北京,100037
2. 长安大学地球科学与资源学院,西安,710054
3. 有色金属华东地质勘查局资源调查与评价研究院,南京210007;中国地质大学,北京100083
基金项目:本文受中国地质调查项目(1212010012012、1212010811033)和国土部公益性行业科研专项(200911007-09、201111007-2)联合资助.
摘    要:本文对北秦岭马河钼矿区桃官坪中-细粒二长花岗岩和西沟斑状二长花岗岩进行了LA-ICP-MS锆石U-Pb年龄测定,分别获得了157±1Ma(NSWD=13)和153±1Ma(NSWD=14)的谐和年龄,表明其为晚侏罗世侵入体。马河钼矿的形成与这两个侵入体密切相关,据此限定该钼矿床成矿时代略晚于157~153Ma,为侏罗世晚期成矿。桃官坪和西沟花岗岩具有高硅(68.12%~76.33%),富碱(Na2O+K2O=6.35%~10.38%)的特征,K2O/Na2O变化较大(0.91~1.89),A/CNK在0.85~1.14之间,为准铝质-弱过铝质高钾钙碱性系列。微量元素上富集U、Pb、Hf等高场强元素,亏损Rb、Ba、K、Sr、P等大离子亲石元素。稀土元素配分曲线为轻稀土相对富集的右倾型,多数具有弱的负铕异常(δEu=0.5~0.9),少数样品具有弱正铕异常(δEu=1.05~1.08)。与华北地块南缘与钼矿有关的花岗岩相比,二者均具有高硅、高钾、富碱的特征。但马河钼矿区成矿花岗岩比华北地块南缘的稍基性,这可能是导致马河钼矿的矿床规模比华北地块南缘较小的原因之一。

关 键 词:花岗岩  LA-ICP-MS锆石U-Pb年龄  地球化学  马河钼矿  北秦岭
收稿时间:2011/9/25 0:00:00
修稿时间:2011/12/1 0:00:00

Geochronology and geological significance of the granites from the Mahe Mo deposit in the North Qinling
KE ChangHui,WANG XiaoXi,LI JinBao and QI QiuJu.Geochronology and geological significance of the granites from the Mahe Mo deposit in the North Qinling[J].Acta Petrologica Sinica,2012,28(1):267-278.
Authors:KE ChangHui  WANG XiaoXi  LI JinBao and QI QiuJu
Institution:1.Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 1 00037,China 2.Faculty of Earth Science and Resources,Chang’an University,Xi’an 71 0054,China 3.Institute of Resource Survey and Assessment,ECE,Nanjing 21 0007,China 4.China University of Geosciences,Beijing 1 00083,China
Abstract:LA-ICP-MS U-Pb dating for the granites from the Taoguanping and Xigou plutons in the Mahe Mo deposit in the North Qinling yields concordant ages of 157±1Ma (NSWD=13) and 153±1Ma (NSWD=14)respectively indicating that the two plutons were formed at late Jurassic. The Mahe Mo deposit is closely related to the two plutons. Therefore these ages may suggest the Mo deposit formed at Late Jurassic appreciably later than 157~153Ma. The granites from the Taoguanping and Xigou plutons are characterized by high in silica (68.12%~76.33%) and alkali (Na2O+K2O=6.35%~10.38%) with the A/CNK of 0.85~1.14 and lager variation of K2O/Na2O (0.91~1.89), showing that they are metaluminous or weakly peraluminous and high-K calc-alkaline series. The Taoguanping and Xigou granites are enriched in U, Pb, Hf, but depleted in Rb, Ba, K, Sr and P. The REE patterns are characterized by enrichment in LREE with weak negative abnormal of Eu (0.5~0.9), but a few samples have weak positive Eu anomalies (1.05 to 1.08). The granites are similar to the molybdenum deposits related granites in the southern margin of the North China Block in enriched in SiO2 and Na2O+K2O. However, these granites are lower in SiO2,Na2O+K2O and higher in CaO and MgO than the granites in the southern margin of the North China Block. It may be one reason that the Mahe Mo deposit is not as larger as the deposits in the southern margin of the North China Block.
Keywords:Granite  LA-ICP-MS zircon U-Pb dating  Geochemistry  Mahe Mo deposit  North Qinling
本文献已被 CNKI 万方数据 等数据库收录!
点击此处可从《岩石学报》浏览原始摘要信息
点击此处可从《岩石学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号