STRAIN ANALYSIS AND EMPLACEMENT MECHANISM OF GRANITE

This paper introduces the method for a strain analysis of the fabric（fo- liation and lineation）of granite by using the theory of the strain ellipsoid.The axial ratio is usually measured on two of the XY,YZ and XZ planes of a xenoiith（or dioritic melanocratic enclave）,then the K value is calculated,i.e. the deformation features may be judged.The metamorphic tabric（plastic deformation）of granite includes boudinage,pressure shadow,domino,shear structure and C-S fabric. Two mechanisms of granite emplacement may be considered:（1）active （forceful）emplacement,such as diapirism and ballooning;（2）passive empla- cement,such as cauldron subsidence and stoping.A detailed knowledge of the mechanism of formation and evolution of magmas,deformation features and regional tectonic environments may be gained through the strain measurement and calculation of granite fabric.