Flow mixing, object-matrix coherence, mantle growth and the development of porphyroclast tails

The kinematic ‘stability fields’ of common porphyroclast types have been defined using a computer program that simulates low Reynolds number Newtonian shearing flow in the vicinity of a rigid spherical object. The principal variables governing the geometry of porphyroclast tails at a given finite shear strain are: (1) porphyroclast-matrix coherence, and (2) mantle recrystallization history, both of which affect the extent to which mantle material becomes mixed with the matrix as deformation progresses.