Porphyroblasts-Matrix Microstructural Relationships from the Crystalline Thrust Sheets of Satluj Valley, Himachal Pradesh

The crystalline thrust sheets of the Lesser and Higher Himalayan region of the Satluj valley, Himachal Pradesh, contain porphyroblasts of gamet, chloritoid, staurolite, kyanite and albite. The inclusion trails in the prophroblasts indicate that the porphyroblasts overgrew during various stages of S2 crenulation cleavage development related to D2 deformation. The sites for nucleation and growth of porphyroblasts are provided by deformation partitioning. The dissolution of porphyroblast margins is not common as suggested by other workers. Metamorphism during D1 was low grade.