Tectono-Geomorphic forcing of the Frontal Sub-Himalayan Streams along the Kimin Section in the Arunachal Himalaya

The Kimin section, located on the frontal part of the Arunachal Himalaya, represents a unique feature of the Sub-Himalaya. The north to south flowing streams, the Singra, Kud, Kimin and the Ranga River are forced to follow a NE-SW trend tor a length of 300m to about 1km in the downstream towards the mountain front due to the presence of faults and shutter ridges along their path. These stream deflections are trending more or less along a linear arrangement mostly, indicating the presence of a prominent NE-SW trending fault extending along the frontal region. The stream courses are also mostly controlled by faults and lineaments trending NE-SW, ENE-WSW, and NW-SE directions. The deflected streams take acute angle to right angled turns and follow their original southward journey being guarded by scarps in a NW to SE channel flow The sandstone bedrocks are dipping away from each other, on the northern and southern parts of the NE-SW trending fault of the frontal region. The frontal streams usually deflect its northward to southward draining channels along this trend of NE-SW. A fault scarp trending NW-SE, exhibits en echelon type of faulting with overlying unconsolidated Quaternary deposits and merges with the Brahmaputra alluvium, suggesting presence of a master normal fault towards south beside the Himalayan Frontal Thrust (HFT).