ABSTRACT
The regional geology of the area in the state of Arunachal Pradesh is divisible into four distinct physiographic domains: Himalayan Ranges, Mishi Hills, Naga-Patkoi Ranges and Brahmaputra plains. The Himalayan regions consist of rocks ranging in age from Proterozoic to Quaternary and have attained the present height during different phases of orogenic movement. Technically the area is in a complex domain of several tectonic features. The major tectonic features are Main Central Thrust (MCT), Main Boundary Trust (MBT), Main Frontal Thrust (MFT), Mishi Thrust, Lohit Thrust, Bomdila lineament and Brahmaputra lineament, which seems to be tectonically active. The area has experienced several phases of deformation which is exhibited by multiple orientations of the deformation features.
