Question

The Himalayas :- Physiography and rive system

Answer 1

Answer:

Physiography of the Himalayas

Physiography of the HimalayasThe Outer Himalayas comprise flat-floored structural valleys and the Siwalik Range, which borders the Himalayan mountain system to the south. Except for small gaps in the east, the Siwaliks run for the entire length of the Himalayas, with a maximum width of 62 miles (100 km) in the northern Indian state of Himachal Pradesh. In general, the 900-foot (275-metre) elevation contour line marks their southern boundary; they rise an additional 2,500 feet (760 metres) to the north. The main Siwalik Range has steeper southern slopes facing the Indian plains and descends gently northward to flat-floored basins, called duns. The best-known of those is the Dehra Dun, in southern Uttarakhand state, just north of the border with northwestern Uttar Pradesh state.

To the north the Siwalik Range abuts a massive mountainous tract, the Lesser Himalayas. In that range, 50 miles (80 km) in width, mountains rising to 15,000 feet (4,500 metres) and valleys with elevations of 3,000 feet (900 metres) run in varying directions. Neighbouring summits share similar elevations, creating the appearance of a highly dissected plateau. The three principal ranges of the Lesser Himalayas—the Nag Tibba, the Dhaola Dhar, and the Pir Panjal—have branched off from the Great Himalaya Range lying farther north. The Nag Tibba, the most easterly of the three ranges, reaches an elevation of some 26,800 feet (8,200 metres) near its eastern end, in Nepal, and forms the watershed between the Ganges and Yamuna rivers in Uttarakhand.