Significance of tourmaline-bearing nanogranite inclusions in garnet from High Himalayan Crystalline sequence, central Nepal

Abstract

Tourmaline-bearing nanogranite inclusions (NIs) are found from the pelitic gneiss collected from the Marsyangdi river area, Nepal Himalayas. Garnet has a rim defined by the discontinuous zoning in Ca and P. The NIs are included throughout the garnet core. ~100μm-sized NIs are composed of Bt+Tur+Chl+Pl+Qtz and Bt+Pl+Qtz, whereas several 10μm-sized NIs are composed of Bt+Ms+Qtz±Chl, etc. Tur-bearing NI is a direct evidence of the presence of B-bearing melt, segregation and ascent of which probably formed the High Himalayan leucogranite bodies.