海南岛小妹韧性剪切带纳米颗粒发育阶段及形成机制

Developmental Stage and Formation Mechanism of Nanoparticles in Xiaomei Ductile Shear Zone on Hainan Island

为了探讨韧性剪切带中纳米颗粒的发育过程和形成机制,进而厘定纳米颗粒对韧性剪切带形成过程和应力机制的指示作用,选取了在小妹韧性剪切带里发育的3种岩石样品(花岗岩、花岗质片麻岩和石英片岩),在扫描电镜下观察其中的纳米颗粒结构及纳米颗粒的聚集形态.观察结果表明:存在2种基本形态——球形的粒状和长条形的柱状,粒状纳米粒子(纳米粒)在3种岩石中都广泛发育,而柱状纳米颗粒(纳米棒)则在花岗质片麻岩中最发育.对纳米颗粒聚集形态研究,可将发育阶段分为:粒化阶段-异化阶段-成层堆积阶段.再次活动时,首先是经过活化阶段,形成复体颗粒,然后再重复上述阶段.结合纳米颗粒形态变化过程,其形成机制可能为脆-韧性变形.

In order to investigate the development process and formation mechanism of nanoparticles in ductile shear zone,three types of rocks were sampled from the Xiaomei ductile shear zone on Hainan island,including granite,granitic gneiss and quartz schist.And the morphology of the nanoparticles was observed by scanning electron microscope（SEM）.The results show that there are two kinds of basic forms of nanoparticles：spherical and columnar,and the nanoparticles（nanograins）are widely developed in all three kinds of rocks.The nanoparticles（nanorods）in granite gneiss are most developed.The aggregated morphology of nanoparticles indicates that the development can be divided into three stages including granulation,alienation and stratification accumulation.The second phase of activity starts with the activation stage which forms complex-nanoparticles,and then repeats the above stage.Combined with the morphological changes of nanoparticles,it is concluded that the formation mechanism is probably brittle-ductile deformation.