Variability of orographic architecture of Indo-Burmese Ranges (NE India) : constraints from morphotectonic and lineament analysis

Activeness of the tectonic and related sub-surface processes control the surface features that lead to variations in topography and lithostratigraphy. To understand the role of active tectonis in shaping the topography, morphotectonic and lineament studies are important. In this study, geological categorization has helped understand the orogenic evolution of the Indo-Burmese Range (IBR), NE India. This is an arcuate hill range that shows many unique topographic characteristics that incited to categorise the entire IBR into different tectonically active domains: Northern (Changlang district of Arunachal Pradesh); Naga Hills; Cachar and Manipur; and Southern (Mizoram). The Northern and Southern domains are more active than the others. Lineament analysis also indicates the presence of active features in the region with NW-SE, NE-SW, ESE-WNW trends are being common. The Northern and Naga Hills domains have mostly E-W younger lineaments whereas the Cachar and Manipur domains rather show N-S younger trends. The Southern Mizoram domain shows a dominance of older N-S lineaments with younger NW-SE lineaments. These variations result from differential stress conditions, i.e. Indian Plate movement and westward stress from the Burma Plate. This study shows how overall variations in tectonic settings can be related to the orogenic evolution.