THE DEFORMATION BEHAVIOUR OF HORNBLENDE IN THE FLORENCE SHEAR ZONE,CENTRAL AUSTRALIA

角闪石在低温变形中通常显示脆性变形行为，通过对中澳洲Ｆｌｏｒｅｎｃｅ剪切带的铁镁质糜棱岩的观察研究表明，角闪石在这些高温变形环境形成的糜棱岩中显示出显著的塑性变形行为，表现在角闪石遭强应变后，无碎裂出现，而具明显的晶内塑性应变现象和强烈的晶体优选定向，角闪石的细粒化是由边界重结晶迁移所致。本文探讨了引起角闪石塑性变形的一些因素，认为岩石发生糜棱岩化时的高温环境增强了角闪石的韧性，几何软化对角闪的塑性变形行为也起到一定的作用。

THE DEFORMATION BEHAVIOUR OF HORNBLENDE IN THE FLORENCE SHEAR ZONE,CENTRAL AUSTRALIA

Amphibole minerals usually exhibit brittle behaviour in low temperature deformation. Observation of microstructural features on some mafic mylonites from the Florence Ductile Shear Zone of central Australia has revealed that the hornblende grains within these high temperature mylonites display extensive plastic deformation behaviour characterized by intensely strained, fracture free hornblendes with pronounced intracrystalline strain features and strong crystallographic preferred orientation. Grainsize refinement of hornblende in the mafic mylonites is a result of the local grain boundary migration. The factors responsible for the plastic deformation behaviour of hornblende have been explored and discussed. High temperature during the mylonitization played an important role in enhancing the ductility of hornblendes and geometrical softening also made some contribution.