Streams and rivers coming from the mountains deposit heavy materials of rocks and boulders in

The Bhabar is a narrow belt, approximately 8-16 km wide, situated at the foothills of the Shivalik range [3]. As rivers descend from the mountains, their velocity decreases due to a lower gradient, causing them to deposit heavy materials such as pebbles, rocks, and boulders [3]. This region consists of coarse debris and alluvial fans that have coalesced over time [1]. Due to the high porosity and permeability of these boulder-strewn beds, smaller streams often disappear underground, only to reappear further south in the marshy Terai region [1]. In contrast, Bhangar represents older alluvium with calcareous 'Kankar' deposits [2], Khadar consists of newer fertile silt in floodplains [2], and Terai is a wet, swampy zone south of the Bhabar [1]. Therefore, the specific zone characterized by the deposition of heavy rock materials at the mountain exit is the Bhabar.

Sources

1. [1] https://www.shivajicollege.ac.in/sPanel/uploads/econtent/cc15cf9bf0ae2213a8754eb93102ce09.pdf
2. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 16: Fluvial Landforms and Cycle of Erosion > Alluvial Fans and Cones > p. 203
3. [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 2: Physiography > 3 The Bhangar Plains > p. 36