Physiography: North and Northeastern Mountains
The Himalayas consist of a series of parallel mountain ranges. The Greater Himalayan range includes the Great Himalayas and the Shiwalik.
Orientation of Himalayan Ranges:
- In northwestern part of India, general orientation is from northwest to the southeast direction.
- In Darjiling and Sikkim regions, Himalayas lie in an eastwest direction.
- In Arunachal Pradesh they are from southwest to the northwest direction.
- In Nagaland, Manipur and Mizoram, they are in the northsouth direction.
The approximate length of the Great Himalayan range, also known as the central axial range, is 2,500 km from east to west, and their width
varies between 160-400 km from north to south.
Due to regional variations within, the Himalayas can be divided on the basis of relief, alignment of ranges and other geomorphological features. These sub-divisions are:
- Kashmir or Northwestern Himalayas
- Himachal and Uttarakhand Himalayas
- Darjiling and Sikkim Himalayas
- Arunachal Himalayas
- Eastern Hills and Mountains.
Kashmir or Northwestern Himalayas
The Kashmir and northwestern Himalayas are well-known for their scenic beauty and picturesque landscape. The landscape of Himalayas is a major source of attraction for adventure tourists.
- Ranges: It comprise a series of ranges such as the Karakoram, Ladakh, Zaskar and Pir Panjal. The northeastern part of Kashmir Himalayas between Greater Himalayas and Karakoram is called a cold desert.
- Kashmir valley: Between Great Himalayas and Pir Panjal lies the valley of Kashmir.
- Glaciers: Important glaciers such as Baltoro and Siachen are also found in this region.
- Karewas: The Kashmir Himalayas are famous for Karewa formations . Karewas are the thick deposits of glacial clay and other materials embedded with moraines and are useful for the cultivation of Zafran, a local variety of saffron.
- Passes: Some of the important passes of the region are:
- Zoji La on the Great Himalayas
- Banihal on the Pir Panjal
- Photu La on the Zaskar
- Khardung La on the Ladakh range
- Lakes: Some important fresh water lakes are Dal and Wular and salt water lakes are Pangong Tso and Tso Moriri. The famous Dal Lake lies between the Great Himalayas and the Pir Panjal. Dal Lake in Srinagar presents an interesting physical feature. Dal Lake is a small part of erstwhile larger lake which provided local base level to Jhelum river causing meanders.
- Rivers: This region is drained by river Indus, and its tributaries like Jhelum and Chenab. Jhelum is in youth stage and yet it forms meanders – a typical feature associated with the mature stage in the evolution of fluvial land form. In Kashmir Valley, the meanders in Jhelum river are caused by the local base level provided by the erstwhile larger lake of which the present Dal Lake is a small part.
- Duns: The southernmost part of this region consists of longitudinal valleys known as ‘duns’. Jammu dun and Pathankot dun are important examples.
- Pilgrimage sites: Some famous places of pilgrimage such as Vaishno Devi, Amarnath Cave, Charar -e-Sharif, etc. are located here.
The Himachal and Uttarakhand Himalayas
This part lies between Ravi in the west and Kali (a tributary of Ghaghara) in the east.
- Rivers: It is drained by two major river systems - Indus and Ganga. Tributaries of Indus and Ganga include:
- Indus: Ravi, Beas and Satluj
- Ganga: Yamuna and the Ghaghara
- Ranges: The northernmost part of the Himachal Himalayas is an extension of the Ladakh cold desert, which lies in the Spiti subdivision of district Lahul and Spiti.
- All the three ranges of Himalayas are prominent in this section also. Great Himalayan range, Lesser Himalayas and Shiwalik range are in parallel from North to South.
- Lesser Himalayas (locally known as Dhaoladhar in Himachal Pradesh and Nagtibha in Uttarakhand) of altitude between 1,000-2,000 m specially attracted British colonialists and subsequently, some of the important hill stations such as Dharamshala, Mussoorie, Shimla, Kaosani and the cantonment towns and health resorts such as Shimla, Mussoorie, Kasauli, Almora, Lansdowne and Ranikhet, etc. were developed in this region.
- The two distinguishing features of this region from the point of view of physiography are the ‘Shiwalik’ and ‘Dun formations’. Some important duns located in this region are the Chandigarh-Kalka dun, Nalagarh dun, Dehra Dun, Harike dun and the Kota dun, etc. Dehra Dun is the largest of all the duns.
- People: In the Great Himalayan range, valleys are mostly inhabited by the Bhotia’s. These are nomadic groups who migrate to ‘Bugyals’ (the summer glasslands in the higher reaches) during summer months and return to the valleys during winters.
- Famous sites: The famous ‘Valley of flowers’ is situated in this region.
- Pilgrimage sites: The places of pilgrimage such as the Gangotri, Yamunotri, Kedarnath, Badrinath and Hemkund Sahib are also situated in this part. The region is also known to have
five famous Prayags (river confluences).
The Darjiling and Sikkim Himalayas
It is relatively small but is a most significant part of the Himalayas. They are flanked by Nepal Himalayas in the west and Bhutan Himalayas in the east. They are also known for their scenic beauty and rich flora and fauna, particularly various types of orchids.
- Rivers: Known for its fast-flowing rivers such as Tista.
- Ranges: It is a region of high mountain peaks like Kanchenjunga (Kanchengiri), and deep valleys. As compared to the other sections of the Himalayas, these along with the Arunachal Himalayas are conspicuous by the absence of the Shiwalik formations. In place of the Shiwaliks here, the ‘duar formations’ are important, which have also been used for the development of tea gardens.
- People: The higher reaches of this region are inhabited by Lepcha tribes while the southern part, particularly the Darjiling Himalayas, has a mixed population of Nepalis, Bengalis and tribals from Central India.
- Tea gardens: The British, taking advantage of the physical conditions such as moderate slope, thick soil cover with high organic content, well distributed rainfall throughout the year and mild winters, introduced tea plantations in this region. Duar formations are important for the development of tea gardens.
The Arunachal Himalayas
These extend from the east of the Bhutan Himalayas up to the Diphu pass in the east. The general direction of the mountain range is from southwest to northeast.
- Rivers: These ranges are dissected by fast-flowing rivers from the north to the south, forming deep gorges.
- Bhramaputra flows through a deep gorge after crossing Namcha Barwa.
- Some of the important rivers are Kameng, Subansiri, Dihang, Dibang and Lohit.
- These are perennial with the high rate of fall, thus, having the highest hydro-electric power potential in the country.
- Ranges: Some important mountain peaks of the region are Kangtu and Namcha Barwa.
- People: An important aspect of the Arunachal Himalayas is the numerous ethnic tribal community inhabiting in these areas.
- Some of the prominent ones from west to east are the Monpa, Abor, Mishmi, Nyishi and the Nagas.
- Most of these communities practise Jhumming. It is also known as shifting or slash and burn cultivation.
- This region is rich in biodiversity which has been preserved by the indigenous communities.
- Transportation: Due to rugged topography, the inter-valley transportation linkages are nominal. Hence, most of the interactions are carried through the duar region along the Arunachal-Assam border.
The Eastern Hills and Mountains
These are part of the Himalayan mountain system having their general alignment from the north to the south direction.
- Rivers: Most of these ranges are separated from each other by numerous small rivers.
- The Barak is an important river in Manipur and Mizoram. Two rivers of Mizoram and Manipur are the tributaries of the Barak river, which in turn is the tributary of Meghna.
- The rivers in the eastern part of Manipur are the tributaries of Chindwin, which in turn is a tributary of the Irrawady of Myanmar.
- Most of the rivers in Nagaland form the tributary of the Brahmaputra.
- Ranges: They are known by different local names.
- In the north, they are known as Patkai Bum, Naga hills, the Manipur hills and in the south as Mizo or Lushai hills.
- These are low hills, inhabited by numerous tribal groups practising Jhum cultivation.
- Lakes: Loktak lake is a large lake at the centre of Manipur surrounded by mountains
from all sides.
- Molassis basin: Mizoram which is also known as the ‘Molassis basin’ which is made up of soft unconsolidated deposits.