Structural control on landscape development of Barak Valley, northeast India

Abstract

The Barak Valley, comprising a contiguous region of three south Assam districts of Cachar, Hailakandi and Karimganj, represents a ridge and valley province with meridional to sub-meridional anticlinal hills and synclinal valleys. Thin skinned tectonics resulted in the deformation of Neogene clastics which is manifested in the form of a series of anticlines and synclines. These structural elements have profound control on the development of present-day landscape in Barak valley. Structurally controlled fluvial erosion produced a series of cuesta ridges and strike valleys which were further subjected to erosional dissection leading to development of numerous topographic highs. Along the northern part of Barak valley adjoining Barail range, three terrace levels stand out with topographic offsets of upto ∼10 m. These terraces are linked to tectonic adjustments along Haflong-Disang Thrust that traverse along the Barail foothills. Numerous wetlands linked to fluvial activities and also isolated from the fluvial domain form a significant element of the Barak valley landscape. Some of these wetlands have their origin to tectonic activities of the region. While the trunk channel of the region follows a nearly E-W trend, all the major tributaries join it at nearly orthogonal position following the prevailing structural trend.