哀牢山构造带南段马玉花岗闪长岩地球化学特征及其锆石U-Pb年龄  

Petrogeochemistry and zircon U-Pb age of the Mayu granodiorite in the southern section of Ailaoshan tectonic belt

作　　者：孙崇波 李忠权 王道永 陈晓东 SUN Chongbo;LI Zhongquan;WANG Daoyong;CHEN Xiaodong(Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation of Ministry of Natural Resources(Chengdu University of Technology/State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology),Chengdu 610059,Sichuan,China;Hydro-Engineering Party of Sichuan Metallurgical Geology and Exploration Bureau,Chengdu 611730,Sichuan,China)

机构地区：[1]自然资源部构造成矿成藏重点实验室(成都理工大学)/油气藏地质及开发工程国家重点实验室(成都理工大学),四川成都610059 [2]四川冶金地质勘查局水文工程大队,四川成都611730

出　　处：《地质通报》2019年第2期223-230,共8页Geological Bulletin of China

基　　金：中国地质调查局项目<西南三江成矿带南段基础地质调查>(编号:1212010880406)和<云南1:5万骂尼街等四幅区域地质矿产调查>(编号:1212011120582)

摘　　要：对云南墨江县马玉花岗闪长岩进行了锆石U-Pb年龄和岩石地球化学分析。LA-ICP-MS锆石U-Pb测年显示,马玉花岗闪长岩年龄为263.6±2.4Ma,形成于晚二叠世。岩石地球化学显示,马玉花岗闪长岩SiO_2含量为59.56%～70.50%,全碱(Na_2O+K_2O)含量为5.16%～7.92%,且Na2O>K_2O;岩石富集轻稀土元素,负Eu异常明显(δEu=0.84～1.32),相对富集Sc、Hf,相对贫化Sr、Zr、Th、U。构造环境判别图解显示,马玉花岗闪长岩形成于碰撞期后板内构造环境,说明哀牢山构造带的古特提斯支洋或弧后盆地在晚二叠世(263.6±2.4Ma)已经闭合。This study presents bulk petrogeochemistry and zircon U-Pb dating results for the Mayu granodiorite in Mojiang,Yunnan.LA-ICP-MS zircon U-Pb dating results show that the Mayu granodiorite was formed in the Late Permian period(263.6 ± 2.4Ma).The Mayu granodiorite is characterized by SiO2 content of 59.56%~70.50%,alkali(Na2O+K2O)5.16%~7.92%,and Na2O higher than K2O.It is enriched in LREE and Sc,Hf,and depleted in Sr,Zr,Th,U,with negative Eu anomalies(δEu:0.84~1.32).According to the diagrams,the Mayu granodiorite was formed in a tectonic environment of island arc-continent or continental-arc collision,indicating that the branch of Paleo-Tethys Ocean or arc basin in Ailaoshan tectonic belt may have been closed in the Late Permian(263.6 ± 2.4Ma).

关 键 词：花岗闪长岩 锆石U-PB测年 岩石地球化学 同碰撞期花岗岩 

分 类 号：P588.122[天文地球—岩石学]