诸广南部岩体群立地区印支期花岗岩地球化学特征及成因

Geochemical Characteristics and Genesis of Indosinian Granite in Qunli Area of the South of Zhuguang Southern Rock Mass

诸广南部岩体是一个复式岩体,结合群立地区花岗岩体元素取样分析结果,讨论了该区印支期花岗岩的地球化学特征及成因。研究表明:(1)印支期花岗岩均以富集大离子元素Rb、Ce、Sm,明显亏损Ba、Sr、Nb、Ta、P、Ti为特征,并经历了较明显的结晶分异作用,其源区为陆壳物质,应属于壳源型S型花岗岩范畴;(2)群立地区的花岗岩体应在该区地壳变薄后,下部泥沙质沉积物熔融形成的花岗质岩浆,在熔体减压驱动机制下发生部分熔融和上升,并沿伸展构造上侵而形成的。

Zhuguang southern rock mass is a compound rock mass, combing with some relate ele- ments analysis results of the samples of Qunli area, the geochemical characteristics and genesis of Indosinian granite are analyzed in detail. The study results show that ：（1）the large ion elements （Rb ,Ce and Sm） is enriched and the elements of Ba, Sr, Nb,Ta,P and Ti are loss of Indosinian granite in Qunli area, the crystallization differentiation Indosinian granite is experienced is obvious, its source region is continental crust materials,which indicated that it is belongs to crustal type and S type granite;（2）after the crustal thinning, the partial melting and rising are of the granitic magma formed by the sediment molten of sediments under the strata in the area is conducted under the influence of melt pressure driving mechanism, the granite rock mass is formed by the upward invasion along the extensional tectonics of granitic magma.