滇西复式花岗岩体的时代及地质意义研究

Study on Geological Age and Implications of Composite Granite in Western Yunnan

对全岩Rb-Sr等时线年龄的研究,得到来利山复式岩体中不同期次岩石的同位素地质年龄:含紫苏辉石斑状黑云母二长花岗岩为84Ma,含斑黑云母钾长花岗岩为77Ma,等粒黑云母钾长花岗岩为52Ma表明来利山复式岩体形成于中生代晚期到新生代早期,说明其演化的比较充分,岩石化学成分的特征反映其物质来源于硅铝的熔融,在成因类型上相当于壳型、S型或改造型。

On the basis of whole rock Rb-Sr isochron ages analysis, isotopic geological ages of the composite granitic rock body from Mountain Lailishan in Western Yunnan were obtained. Age of hypersthene-bearing speckled biotite monzonific granite is 84Ma, age of speckled biotite rnoyites is 77Ma, and age of consertal fabric biotite moyites 52 Ma. The results show that the composite granitic rock body from Mountain Lailishan is formed during late Mesizoic and early Cenozoic. Evolution of the rock mass is sufficient. The chemical composition of the rock mass indicates that substance source of the rocks is melted silicon and calcium. The genesis style of the rock mass belongs to shell style, S style or reform style.