江西省金溪—南城混合岩和花岗岩的岩石地球化学及同位素地球化学研究  

Petrology and Isotopic Geochemistry of Jinxi-Nancheng Migmatites and Granites, Jiangxi Province

作　　者：胡恭任[1] 于瑞莲[1] 刘丛强[2] 

机构地区：[1]华侨大学材料科学与工程学院,福建泉州362011 [2]中国科学院地球化学研究所,贵州贵阳550002

出　　处：《岩石矿物学杂志》2001年第2期103-111,共9页Acta Petrologica et Mineralogica

基　　金：福建省自然科学基金! (D9910 0 16 );南京大学内生金属矿床成矿机制研究国家重点实验室开放基金;华侨大学科研起动资金资助

摘　　要：在研究金溪—南城变质混合岩带中混合岩、花岗岩的矿物岩石学基础上 ,详细研究了它们的Nd、Sr、Pb、O同位素组成。混合岩、花岗岩初始钕同位素组成 (14 3Nd/14 4 Nd) i=0 .5116 89～0 .511853,在εNd -T图中位于该地区结晶基底变粒岩、片岩Nd同位素演化域上方 ,褶皱基底绢云千枚岩Nd同位素演化线下方 ;初始锶同位素组成 (87Sr/86 Sr) i=0 .74 86 4～ 0 .752 57;氧同位素组成δ18O为 10 .2 3‰～ 14.89‰ ,相当于高氧花岗岩的氧同位素变化范围 (>10‰ ) ;放射性成因铅较低 ,μ =10 .0 7～ 10 .4 ,变化范围小 ,铅同位素组成位于上部地壳演化线上方。这表明混合岩、花岗岩是由成熟度高、富氧的变粒岩及片岩等变质沉积岩经部分重熔形成的。Jinxi-Nancheng metamorphic migmatite zone composed mainly of Jinxi igneous mass amd controlled by various ductile shear zones is a multi-facies, multi-type and progressive metamorphic zone. On the basis of a comprehensive petrological and mineralogical study of Jinxi-Nancheng metamorphic migmatite zones, their Nd-Sr-Pb-O isotopic geochemistry has been investigated in detail. The initial Nd and Sr isotopic compositions of migmatites and granites are 0.511689～0.511853 and 0.74864～0.75257 respectively. δ 18O values of migmatites and granites are 10.23‰～14.89‰, similar to the δ 18O values of high O granites(>10‰). Below the evolution line of sericite schist of folded-basement in the εNd-T evolution diagram, initial Nd isotopic composition of migmatites and granites is apparently located in the evolution area of granulitite and schist of crystalline-basement. Their contents of radiogenic Pb are relatively low, with μ being 10.07～10.4, and their Pb isotopic compositions are above the evolution line of the upper crust. The above features show that migmatites and granites in Jinxi-Nancheng migmatite zone are formed by partial remelting of O-rich and highly-matured granulitite and schist.

关 键 词：岩石学 花岗岩 同位素地球化学 钕 锶 铅 氧 金溪-南城变质混合岩带 江西 

分 类 号：P588.3[天文地球—岩石学] P588.121[天文地球—地质学]