Geochronologic and petrochemical evidence for the genetic link between the Maomaogou nepheline syenites and the Emeishan large igneous province  

作　　者：LUO ZhenYu XU YiGang HE Bin SHI YuRuo HUANG XiaoLong 

机构地区：[1]Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [2]Graduate University of the Chinese Academy of Sciences, Beijing 100049, China [3]Beijing SHRIMP Center, Beijing 100037, China

出　　处：《Chinese Science Bulletin》2007年第7期949-958,共10页

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 40421303 and 40234046)

摘　　要：The Maomaogou nepheline syenite is located at the inner zone of the Emeishan large igneous province and exhibits intrusive contact with the Emeishan basalts. SHRIMP U-Pb dating on zircons from this syenite yields an age of 261.6±4.4 Ma, in agreement with the age of the Panzhihua layered intrusion and the eruption age of the Emeishan basalts as constrained by stratigraphic data. Geochemical data fur-ther suggest that the Maomaogou syenite has a source analogue to the Emeishan basalt, and may have been formed by partial melting of gabbroic cumulates underplated in the lower crust. As s result, tem-poral and spatial relationships and petrogenetic constraints provide evidence for the genetic link be-tween basalts, mafic/ultramafic and intermediate/acidic intrusives in the Panxi area.The Maomaogou nepheline syenite is located at the inner zone of the Emeishan large igneous province and exhibits intrusive contact with the Emeishan basalts. SHRIMP U-Pb dating on zircons from this syenite yields an age of 261.6±4.4 Ma, in agreement with the age of the Panzhihua layered intrusion and the eruption age of the Emeishan basalts as constrained by stratigraphic data. Geochemical data further suggest that the Maomaogou syenite has a source analogue to the Emeishan basalt, and may have been formed by partial melting of gabbroic cumulates underplated in the lower crust. As s result, temporal and spatial relationships and petrogenetic constraints provide evidence for the genetic link between basalts, mafic/ultramafic and intermediate/acidic intrusives in the Panxi area.

关 键 词：会理县猫猫沟 霞石正长岩 峨眉山 岩石成因 相关性 地质年代 地球化学 

分 类 号：P588.122[天文地球—岩石学] P588.192[天文地球—地质学]