Late andalusite and cordierite growth

A few samples containing rare porphyroblasts of andalusite (C55B, C101, C92A), cordierite (C66, C68A, C68B, C96B, C70, C101) and fibrolitic sillimanite (C55B, C66, C70, C68B, C92A, C96B and C101) generally only showed these phases in one thin section of the 8 to a maximum of 18 that were cut from each sample. Consequently, a FIA could not be measured. Indeed, the porphyroblasts overgrew the matrix with no deflection of the foliation from inside to outside of the porphyroblast, suggesting that they formed after deformation ceased. The location of these samples and the three isograds that they suggest is shown in Fig. 19c, d.