Abstract:
In this study, an inverted metamorphic sequence in the western Arunachal
Himalaya (WAH) is reconstructed using combined structural and metamorphic
analyses of rocks of the Lesser and Greater Himalyan Sequences (LHS and GHS
respectively), which are exposed along the transect, Sessa-Rupa-Bomdila-Dirang-Se
La. Five metamorphic zones from garnet through kyanite, kyanite migmatite, kyanitesillimanite
migmatite to K-feldspar-kyanite-sillimanite migmatites are sequentially
developed in the metamorphosed low-alumina pelites with increasing structural
heights. In the garnet-zone, peak metamorphism is marked by post-D2 garnet growth
through biotite+plagioclase→garnet+muscovite reaction. An even earlier phase of
syn-D1 garnet growth occurred in the chlorite stability field with or without epidote.
