Fractured Clast

Thin section of fractured porphyroclast within a ductile shear zone. The fractured clast shows top to the right sense of shear. The microfaults cutting the clast are at a relatively low angle to the foliation (oriented approximately left-right) in the shear zone. Thus, the fractured clast has the same sense of shear as the shear zone (i.e., it is synthetic). Image from website by M. Jessell, P. Bons & P. Rey: http://www.earth.monash.edu.au/Teaching/mscourse/index.html