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(143Nd/144Nd)i=0.511689～0.511853,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/86Sr)i=0.74864～0.75257;氧同位素组成δ18O为10.23‰～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=10.07～10.4,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. δ18O values of migmatites and granites are 10.23‰～14.89‰, similar to the δ18O 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.
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