湖南香花岭430花岗岩体Nd同位素特征及岩石成因

Nd isotopic characteristics and genesis of Xianghualing 430 granitic body, Hunan Province

研究了香花岭地区 430花岗岩体由深部到浅部以及线状云英岩、面状云英岩的εNd(t)、t2DM值、fANd值变化特征。Nd同位素特征说明该花岗岩为壳 -幔组分混合的花岗岩 ,同时反映了源自深部的幔源物质加入及其在岩体中分布的不均一性 ,认为地幔物质可能主要是以地幔流体的形式加入 ,在华南中生代岩石圈减薄的背景下 ,幔源流体底侵诱导中元古代地层重熔。

This paper has studied characteristic values and upward changing tendency of ε Nd ( t ), t 2 DM and f A Nd in granitic rocks of 430 granite body as well as the variation of these values in linear_ and planar_greisens of Xianghualing. Nd isotopic characteristics of rocks suggest that the granite resulted from the mixing of the crust material with the mantle material, and that the mantle material derived from the deep source got into and was distributed unevenly in the granite body. The mantle material might have mainly taken the form of mantle fluid to join the process of granitic evolution. Under the Mesozoic background of lithosphere thinning in East China, the mantle fluid underplating induced the remelting of Mesoproterozoic strata, forming granitic magma.