Geometric Shape and Variation in Dynamic Nature of the Depositional Geomorphic Surface under Neotectonic Settings in the North Bengal Foothill of the Eastern Himalayas, India

High surface runoff due to monsoonal precipitation and glacier melting water of the greater Himalayas causes perennial conditions of the streams of the eastern Himalayas. The basins of the streams of the study area show highly weathered geological formations that are prone to erosion under a neo-tectonic environment and the resultant production of huge sediments that form a colony of depositional geomorphic surfaces in a triangular or almost triangular shape at the foothills. FCi analyses that the depositional geomorphic surfaces of the study area are alluvial fans. TCo & FCo analysis advocates for a higher dynamic nature of the alluvial fansin the east of the study area than west under relatively stable neo-tectonic conditions.As a result, the large alluvial fans are found in the east of the study area.