华南中生代同熔系列花岗岩类的Nd-Sr同位素特征及成因讨论

本文讨论了华南20个同熔系列花岗岩类的Nd-Sr同位素组成。根据样品的同位素组成及其在￠Nd-T,(87Sr/86Sr)i-T和￠Nd-￠Sr图上的分布特征,认为这些同熔系列花岗岩类是华南上地壳端员和亏损地幔端员按一定比例混合的产物。利用简单二元混合方程计算了这些花岗岩体的壳幔混合比例。根据产出的大地构造环境和物质来源,华南同熔系列花岗岩类可划分为三种类型:大陆边缘型,大陆内部型和断裂拗陷带型。

Nd-Sr Isotopic Characteristics and Genetic Discussion of Mesozoic Granitoids of Syntexis Series in South China

Nd-Sr isotopic compositions for 20 granitoid bodies of syntexis series in South China have been studied in this paper. Based on the isotopic compositions of samples and their distribution characteristics on the _(Nd)-T, (~(87)Sr/~(86)Sr)_i-T, and _(Nd)-_(Sr) diagrams, these granitoids of syntexis series are considered as mixing products of upper crust end-member and depleted mantle end-member in certain proportion. Crust-mantle mixing proportions of these granitoids are calculated by using the two-component mixing equations. According to tectonic environments and material sources, granitoids of syntexis series in South China can be divided into three types: the continental margin type, the continental interior type, and the fault depression zone type.