| Summary: | The Bhagirathi leucogranite forms a series of low-angle en echelon, lensoidal intrusions at the top of the High Himalayan slab in the central Himalaya of Garhwal, northern India. The Bhagirathi leucogranite is situated structurally above the kyanite and sillimanite gneisses of the Vaikrita Group which, in turn, overlie the north-dipping Main Central Thrust zone of inverted metamorphic isograds. Various shear criteria in the gneisses immediately below the granite document the existence of a major zone of ductile NNE-SSW-directed extension across a northeastward dipping, low-angle normal fault zone. The northward-dipping Bhagirathi leucogranite was intruded syn-tectonically during the ductile to brittle transition and has been deformed into linked, en echelon bodies within the extensional shear zone at the interface between the Vaikrita Group gneisses and the Tethyan sedimentary cover. During extension, sub-orthogonal dilatational forces exceeded sub-horizontal shear stresses thus facilitating the repeated emplacement of sheeted granite melt, a process analogous to low-angle tension gash development. -from Authors
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