缅甸硬玉岩地球化学特征及其地质意义  

Geochemical characteristics of jadeitite from Myanmar and its geological significance

作　　者：李强[1] 李坚玲[1] LI Qiang;LI Jianling(Yunnan Land and Resources Vocational College,Kunming 650217,Yunnan,China)

机构地区：[1]云南国土资源职业学院,云南昆明650217

出　　处：《矿产与地质》2023年第5期987-994,共8页Mineral Resources and Geology

基　　金：云南省教育厅科学研究基金(项目编号:2020J0963);应用地质与矿产地质科技创新团队(项目编号:2022KJTD02)共同资助。

摘　　要：缅甸硬玉岩是一种与超基性岩密切相关的岩石。通过硬玉岩主量成分、微量元素和稀土元素地球化学特征研究表明,缅甸硬玉岩属过碱性系列。稀土总量在(0.2~10.13)×10^(-6)之间,为贫稀土类型。LREE/HREE比值平均为3.5,轻稀土相对富集,稀土元素球粒陨石标准化模式图较缓向右倾斜。δCe无异常,δEu轻度正异常。富集不相容元素Cs、Ba、Th、U、Pb、Sr和高场强元素Zr、Hf,亏损Nb、Ta和Ti,岩浆来自富集地幔2(EM_(2))。Th/Ta=6.2(>1.6),Ta/Hf=0.056(<0.1),其大地构造环境为岛弧环境。缅甸硬玉岩是新特提斯演化过程中,幔源岩浆上侵,加入陆源物质后,经过复杂的岩浆结晶、交代作用形成的矿床,后期受一定程度的变质改造。Myanmar jadeitite is closely related to the ultrabasic rock.The geochemical characteristics of major elements,trace elements and rare earth elements of Jadeitite shows that the rock type belongs to peralkaline series.The total amount of rare earth elements ranges from 0.2×10^(-6) to 10.13×10^(-6),and it is a REE-poor type.The average value of LREE/HREE is 3.5,the light rare earth elements are relatively rich,and REE chondrite-standardized pattern diagram inclines slowly to the right.δCe is normal,butδEu is slightly positive anomaly.The incompatible elements such as Cs,Th,U,Pb,Sr and high field strength elements Zr,Hf are enriched,but Nb,Ta and Ti are deficient.The magma comes from the enrichment mental 2(EM_(2)).Th/Ta=6.2(>1.6),Ta/Hf=0.056(<0.1),and its tectonic environment is island arc environment.Myanmar jadeitite is a deposit formed by the complex magma crystallization and metasomatism after mantle-derived magma invading and mixing with terrigenous materials during the evolution of Neo-Tethys,and it is reformed by a certain degree of metamorphism in the later period.

关 键 词：硬玉岩 地球化学特征 地质意义 缅甸 

分 类 号：P588.125[天文地球—岩石学]