Structural Framework and Granite-Induced Contact Metamorphism in the Lesser Himalayan Sequence of Doda District, Jammu and Kashmir

ABSTRACT Geological mapping of the Hambal-Dedni area of Doda District, Jammu and Kashmir, was undertaken to investigate the structural and metamorphic evolution of the Lesser Himalayan Sequence (LHS). The area exposes Proterozoic phyllites of the Salkhala Formation, intruded by the Palaeozoic Dedni Granite and cut by younger aplite veins, gabbro, and quartz veins. The granite-metapelite contact is marked by a 10–15 m wide aureole. Two phases of deformation were identified: an early D1 event that produced regionally developed S0//S1 foliation and tight to isoclinal F1 folds, followed by D2 open folds and crenulation cleavage (S2). π-pole analyses of S0 and S1 confirm a regional syncline with the Dedni Granite occupying the core. Metamorphic assemblages in the Salkhala Formation reflect regional greenschist facies conditions, locally overprinted by contact metamorphism near the granite. Garnet-biotite thermometry, evaluated using seven calibrations, yields peak contact aureole temperatures of 530–560°C from the most consistent formulations, while Ti-in-biotite thermometry provides complementary values of 443–445°C. Together, these results demonstrate localised thermal gradients across the aureole and emphasise the role of granitoid intrusions in modifying the metamorphic architecture of the Lesser Himalayan crust.