Figure 6.22h. Garnet Reaction Bands. Reaction bands of garnet (Grt) and clinnopyroxene (Cpx) separating plagioclase (Pl) and orthopyroxene (Opx) in an Opx gneiss are evidence for the reaction Opx + Pl + Qz = Grt + Cpx. Producing this texture requires nearly isobaric cooling. The field of view is 4 mm across. J.T. Cheney photo.
