Page 233 - Microtectonics

7.6 · Problematic Porphyroblast Microstructures 223

Fig. 7.48. Chloritoid crystal with textural sector zoning in hourglass shape, controlled by crystal habit. A shape orientation of S is visible
i
in two sectors, suggesting a relative crystal rotation of 60° with respect to the matrix. Leiden Collection. Width of view 4 mm. PPL

Fig. 7.49. Layered chloritoid schist with almost euhedral chloritoid crystals that show both hourglass zoning and a rhythmic concentric
layer-zoning of inclusion-rich and poor areas. A gentle crenulation has developed by D that is also present in the crystals, indicating that
2
they grew late syn-D 2 . Açunguí, São Paulo, Brazil. Width of view 17 mm. PPL