同构造花岗岩的一种显微构造标记  

A microstructure marker of syntectonic granitoids

作　　者：谢才富[1] 

机构地区：[1]中国地质调查局花岗岩地质研究室,湖北宜昌443003

出　　处：《岩石矿物学杂志》2002年第2期179-185,共7页Acta Petrologica et Mineralogica

基　　金：中国地质调查局国土资源大调查资助项目 (2 0 0 1390 0 0 18)

摘　　要：在许多同构造花岗岩中 ,发现一种不同于糜棱基质的微细粒矿物集合体———微粒交生体 ,充填于大粒级矿物的三结点和接合缝内 ,体积分数一般为 2 %～ 6 % ,由微粒石英、斜长石、钾长石、蠕状石等组成 ,成分上与花岗质岩浆的晚期结晶产物相当。根据其产状、成分、岩相学特征及有关实验资料 ,认为它是较强应力作用下岩石所含少量残余熔体 (质量分数约小于 3%～ 5 % )的结晶产物 。In many syntectonic granitoids, micro_intergrowth, a kind of micrograined mineral aggregates different from mylonization matrix, has been found. It fills in the seams and triple junction channels among the larger mineral grains, generally with a content of 2%～6% in the rocks. It consists mainly of micrograined quartz, albite, potassic feldspar, myrmekite, etc., and can be divided into two types: granular and myrmekitic intergrowth. In composition, it is just like a late crystallized product of granitic magma. According to the characteristics of its occurrence, composition, petrography and the experimental conclusion that the dominant deformation mechanism will change into dislocation creep when the melt content in the rock is lower than 3%～5%, it is suggested that micro_intergrowth is a crystallization product of a small amount of residual melt (about <3%～5%) in rocks under strong stress. So it can be considered generally as a microstructure marker of synkinematic crystallization in intrusions.

关 键 词：微粒交生体 花岗质岩石 塑性变形 熔体结晶 变形机制转变 同构造 

分 类 号：P588.121[天文地球—岩石学]