Page 232 - Microtectonics

222 7 · Porphyroblasts and Reaction Rims

Fig. 7.46. Staurolite garnet biotite schist with a staurolite crystal (at left) that shows textural sector zoning and cleavage domes. S i in the
sectors mimics S rotated over about 30°. The foliation is strongly deflected around the garnet crystal without inclusions at the right-hand
e
side of the photograph. Based on the deflection patterns, it can be concluded that garnet grew first, then staurolite and finally biotite (the
dark patches in the matrix), all during the deformation phase that produced the foliation (syntectonic porphyroblast growth). Orós, NE
Brazil. Width of view 10 mm. PPL

Fig. 7.47. Biotite schist with porphyroblasts of chiastolite showing re-entrant zones with feather-edge structures. Density of inclusions is
controlled by crystal habit. Growth inclusions occur in the larger crystal. Laraquete, central Chile. Width of view 16 mm. Polars at 45°