摘要
对西秦岭造山带郎木寺火山岩进行了岩相学、锆石U-Pb年代学、主量元素和微量元素地球化学研究。郎木寺火山岩主要由安山岩组成,锆石LA-ICP-MS的U-Pb定年,获得郎木寺火山岩的结晶年龄为217±4 Ma。郎木寺火山岩亲石元素(LILE)富集,高场强元素(HFSE)相对亏损,Σ_(REE)总量为195.9~418 ppm,(La/Yb)_(N)=12.16~13.93,δ_(Eu)=0.72~0.81,表明郎木寺火山岩的岩浆源区主要来源于陆壳物质,由幔源岩浆底侵作用引起的下地壳部分熔融形成,岩浆产生机制可能为在碰撞后构造伸展阶段的岩石圈拆沉作用。
An integrated study of petrology,zircon U-Pb dating and geochemistry for the Langmusi volcanic rock in the middle part of the west Qinling were carried out.The Langmusi volcanic rocks consist of andecite and trachyandecite.Results show that the zircon LA-ICP-MS U-Pb age of the Langmusi volcanic rocks is 217±4 Ma.The Langmusi volcanic rocks are characterized by enrichments of LILE(e.g.Rb,Ba,U,Th,Pb)and HFSE(e.g.Ta,Nb)depletion,withΣ_(REE)=195.9~418 ppm,(La/Yb)_(N)=12.16~13.93,δ_(Eu)=0.72~0.81,which show the magma of the volcanic rocks was dominantly derived from crustal materials.The Langmusi volcanic rocks were generated by partial melting of lower crust,granodiorite and volcanic rock resulted from lithospheric delamination in post-collisional setting.
作者
代连铎
DAI Lian-duo(Liaoning Nonferrous Geology 105th Team Co.,Ltd.,Huludao 125000,China)
出处
《有色矿冶》
2024年第1期1-4,12,共5页
Non-Ferrous Mining and Metallurgy
