The Himalayas

India is a land of physical diversities.

According to one estimate, 29.3(hills + mountains) per cent of area of India is occupied by mountains (11%) and hills (18%), 27.7 per cent by plateaus and 43 per cent by plains

From a physiographical point of view, India can be divided into following four regions:

1. Great Northern Mountains
2. Great Northern Plains
3. Great Indian Plateau and
4. Coastal Plains and Islands.

Great Northern Mountains-

• Himalayas run in 2400 km. length with a width of 160 km. to 400 km.
• Their extension is between 22 longitudes. The average height is 6000m.

• They have loftiest peaks of the world. The sedimentary rocks of Himalayas are folded and faulted.

• They have a number of over folds, recumbent folds, nappes, and thrust faults. These are still in the stage of formation

• Their extension is from Nanga Parbat in the west and Namcha Warba in the east.

• Orientation these ranges is from northwest to the southeast direction in the north western part of India

• Himalayas in the Darjeeling and Sikkim regions lie in an east west direction, while in Arunachal  Pradesh they are from southwest to the northwest direction

• In Nagaland, Manipur and Mizoram, they are in the north south direction.

Himalayas are classified into 2 Broad categories

A.Geographical basis

B.Regional basis

A.Geographical basis

Under this group Himalayas are classified on the basis of overall geography of Himalayas and it is further divided as follows

1.The Himalayas
(i) Inner or Great Himalayas/ Himadri
(ii) Lesser or Middle Himalayas/ Himachal
(iii)Sub- Himalayas or Siwalik

2.The Trans-Himalayas
3. Purvachal or the hills of the North-East

• This is the highest mountain range of the world The southern slopes of Himalayas facing India are steeper and those facing the Tibetan side are generally gentler. 

• The Himalayas in the eastern region have a steep rise from the plains of West Bengal and Assam. This proximity to the plains means that two of the tallest peaks in the Himalayas, Mt. Everest (located in Nepal) and Kanchenjunga, are not far from these areas.

• Conversely, in the western region, the Himalayas have a more gradual ascent from the plains.

•  Hence, the higher peaks in this part are farther from the plains and a number of ranges lie between the plains and high peak.

• This is the northern most and the highest range of the Himalayas

• The Inner or Great Himalayas, also known as Himadri, is characterized as the most unbroken(continuous) chain of mountains in the Himalayan range.

•  Its composition consists primarily of granite rocks at its core, with metamorphic and sedimentary rocks forming its flanks.

• The extent of this range is between the Nanga Parbat peak (8126 m.) in the west and Namcha Barva peak (7756 m.) in the east

Peaks -

• It has eight peaks of more than 8000m height. Highest peak is Mt. Everest also known as Queen of mountains

• It is also named as Gauri ShankerKanchenjunga, Makalu, Dhaulagiri, Annapurna are some of the other peaks having a height of more than 8000 metres. Kanchenjunga is the highest peak of Himalayas in India

Passes-

• The Burzil pass and the zoji La in Kashmir

• The Bara Lacha La and shipki La in Himachal Pradesh

• The thag La, Niti pass and Lipu Lekh pass in Uttarakhand

• The Nathu La and Jelop La in Sikkim are important passes through the Himadri.

• It is located southwards of Himadri

• Some of the peaks of this range have a height of more than 5000 metres. The Lesser or Middle Himalayas are characterized by a rugged and fragmented landscape.

• Rocks in this region have undergone metamorphosis due to intense pressure and thrusts. The mountains are primarily composed of Pre-Cambrian and Paleozoic rocks, including slate, limestone, and quartz.

• While the south-facing slopes are typically steep and barren, the north-facing slopes are covered in thick vegetation.

Ranges -

• These Himalayas include a number of ranges like Pir Panjal, the Dhaola Dhar, the Mussoorie Range, the Nag Tiba
• The Pir Panjal is its western extension, and occupies its Position in Kashmir. It is the longest and most important range.

• The beautiful valley of Kashmir extends between the Pir Panjal and Himadri ranges

Passes-

Pir Panjal (3494m) and Banihal (2832m) are two main passes. The Banihal pass is used by Jammu -Kashmir highway

Valleys-

Two open valleys are found between middle and Great Himalayas. 

• In west, Kashmir valley is extended between Pir Panjal and Great Himalayas

• In east, Kathmandu valley is situated in Nepal and in Himachal Pradesh Kangra and Kullu valley

Origin of kashmir valley-

• Kashmir Valley is believed to have been occupied by a lake during the Pleistocene age.
• The basin was filled with sediment and uplifted to form the valley.
• The valley's synclinal basin is covered with diverse alluvial deposits.
• The meanders in the Jhelum River in the valley are caused by the former larger lake's local base level, of which Dal Lake is now a small part.

• The southernmost range of Himalayas is known as Siwalik.. This chain of hills runs almost parallel to the lesser Himalayas for a distance of 2400km.

• It spreads from the Potwar Plateau in Punjab to the Brahmputra valley in Arunachal Pradesh.

• It varies from 50km in Himachal Pradesh to less than 15km in Arunachal Pradesh.

• These are known by different names, such as Jammu hills in Jammu, Dafla, Miri, Abor and Mishmi hills in Arunachal Pradesh

• The Shivaliks are formed of great thickness of Mio -Pleistocene sands, gravels and conglomerates which have been brought by the rivers flowing from the higher ranges of the Himalayas. These have very high uneven surface.

• The gravel, sand, and mud carried by rivers originating from the Himadri and Himachal ranges were deposited in the Tethys Sea as it rapidly receded.

Valleys–

There are found a number of valleys between, Shiwaliks

• These are like plains called ‘duns’ or ‘Doons’ in the west and ‘Duars’ in the east.

• The Duns are the discontinuous series of longitudinal vales. Dehradun in Uttarakhand is the best example of such plain

• It is covered with boulder and clay deposits. It is a flat-bottomed strike valley. The other Dun v alleys are- Udhampur Kotli in Jammu, Kotah, Patli, Chumbi, Kyarda, Chaukhamba and Kothri in Uttarakhand and Himachal Pradesh.

•  These are also quite typical. The range is covered with thick, tropical west deciduous forests

•  The southern slopes of the range are barren, and highly dissected by several seasonal streams locally called ‘Chaos’.

There are some mountain ranges to the north of the Himadri in Jammu and Kashmir(explained, by Sven Hyden in 1906 for the first time)

Rock-

• These are formed of sedimentary deposits. They have the rocks of Cambrian to Tertiary Period.

Peaks-

• Mt K2 (8611m), the second highest peak of the world, Hidden Peak (8068m), Broad Peak (8047m) and Gasherbrum II (8035m).

Glaciers-

• The largest glaciers are Hispar and Batura of the Hunza Valley and Biafo and Baltoro of the Shigar Valley.The Siachin glacier of the Nubra Valley is the longest one with a length of over 72 km.

Ranges - The Zaskar, Kailesh, Laddakh and Kara-Koram are the main ranges of these Himalayas

A.Zaskar range -

• The mountain range situated north of the Himadri and running parallel to it is referred to as the Zaskar range. Beyond the Zaskar range lies the Ladakh range.

• The Indus River flows in a northwest direction between the Zaskar and Ladakh ranges. Some experts consider the Zaskar and Ladakh ranges to be a constituent of the Great Himalayas and encompass them in the Kashmir Himalayas.

B.Karakoram -

• The Karakoram range is located north of the Ladakh range.
• The range is referred to as Krishnagiri in Sanskrit literature.
•  K2, standing at 8611m, is the highest peak in the Karakoram range.
• The peak is the second-highest in the world, after Mt. Everest.
• Towards the west, the Karakoram range merges into the Pamir Knot.
• Towards the southeast, it is merged into the Kailash Range in Tibet.

C.Ladakh plateau

• It is situated in the north eastern part of the state of Jammu and Kashmir.
• Areas - Lingzi Tang Plains, Lokzhung Mountains, Aksai Chin and Soda Plains etc.

D.Kailash Range

• It is an offshoot of the Laddakh Range. It is extended mainly in Tibbet. North of the Indus is the great Kara -Koram a region of lofty peaks and vast glaciers. Here India’s frontier is joined with China and Afghanistan

• Purvachal refers to the hills located in North East India beyond Brahmaputra gorge.
• The major hilly ranges of this region include Mishmi, Patkoi Bum, Naga, Manipur, Mizo (Lushai), and Tripura.
• The Meghalaya Plateau is also part of the hills of the North Eastern region, including the hills of Garo, Khasi, and Jaintia.
• These hills are known for having the same origin as the Himalayas.
• Patkoi Bum is located in the northern hills, which merge with the Naga Hills in the south.
• The highest peak of Naga Hills is Saramati, which has an elevation of 3826m.
• Structurally, the Meghalaya Plateau is part of the Peninsular India region.
• Barail range separates Naga Hills from Manipur Hills, which are extended in the south of Naga Hills.
• The elevation of eastern hills decreases from north to south

Regional division of Himalayas

The Himalayas can be classified into different sub-divisions based on their relief, alignment of ranges, and other geomorphological features. These sub-divisions are commonly referred to as the regional division of the Himalayas.

(i) Kashmir or Northwestern Himalayas

(ii) Himachal and Uttarakhand/Kumaon Himalayas

(iii) Darjiling and Sikkim Himalayas

(iv) Arunachal Himalayas

(v) Eastern Hills and Mountains.

• The region known as Kashmir or Northwestern Himalayas comprises several ranges including Karakoram, Ladakh, Zaskar, and Pir Panjal.
• The southernmost part of this region has longitudinal valleys called 'duns,' with Jammu dun and Pathankot dun being notable examples.
• Srinagar, the capital city of Jammu and Kashmir, is situated on the banks of the Jhelum river. The Dal Lake in Srinagar is a unique physical feature.
• The Jhelum river in the Kashmir valley is still in its youth stage, but it forms meanders, which is a typical feature associated with the mature stage in the evolution of fluvial landforms.

 Glaciers -

• Important glaciers of South Asia such as the Baltoro and Siachen are also found in this region.

Karewa -

• The region of Kashmir Himalayas is well-known for its Karewa formations that provide favorable conditions for cultivating Zafran, a type of saffron grown locally.

Passes -

• The region boasts several significant mountain passes, including Zoji La in the Great Himalayas, Banihal in the Pir Panjal range, Photu La in the Zaskar range, and Khardung La in the Ladakh range.

Lakes-

• The region is home to several significant lakes, including freshwater lakes like Dal and Wular, as well as saltwater lakes such as Pangong Tso and Tso Moriri.

Rivers-

• This region is drained by the river Indus, and its tributaries such as the Jhelum and the Chenab.

• The region of Himachal and Uttarakhand Himalayas is drained by two major river systems in India- the Indus and the Ganga.
• Geographically, this area lies between the Ravi river in the west and the Kali river (a tributary of Ghaghara) in the east.
• The northernmost part of the Himachal Himalayas is an extension of the Ladakh cold desert in the Spiti subdivision of district Lahul and Spiti.
• The Great Himalayan range, the Lesser Himalayas (known locally as Dhaoladhar in Himachal Pradesh and Nagtibha in Uttarakhand), and the Shiwalik range are all prominent in this area.
• The region is characterized by two distinctive features in terms of physiography- the Shiwalik and Dun formations.
• Some significant duns present in this region include the Chandigarh-Kalka dun, Nalagarh dun, Dehra Dun, Harike dun, and the Kota dun.
• The largest of all the duns in this region is Dehra Dun.

• Bhotia’s -The Bhotia people reside in the valleys of the Great Himalayan range. They are nomadic groups who move to the higher reaches, known as "Bugyals," during the summer months to graze their livestock and then return to the valleys in the winter.

• The famous ‘Valley of flowers’ is also situated in this region.

Extension-

• The region located between Nepal Himalayas in the west and Bhutan Himalayas in the east is considered to be a crucial part of the Himalayas.

• It is Known for its fast-flowing rivers such as Tista,

• Despite being relatively small in size, it is known for its impressive high mountain peaks such as Kanchenjunga (Kanchengiri).

Lepcha tribes -

• The upper areas of this locality are populated by the Lepcha community, while the southern region, specifically the Darjeeling Himalayas, has a diverse populace consisting of Nepalis, Bengalis, and tribes originating from central India.

Favorable conditions for tea plantation-

• Moderate slope, 

• Thick soil cover with high organic content, 

• Well distributed rainfall throughout the year and mild winters are found in this region.

In place of the Shiwaliks here, the ‘duar formations’ are formed, which have also been used for the development of tea gardens.

Extension-

• 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.

Important mountain peaks -

• Kangtu and Namcha Barwa.

• Bhramaputra flows through a deep gorge after crossing Namcha Barwa.

Important rivers -

• The Kameng, the The Shiwalik , Subansiri, the Dihang, the Dibang and the Lohit  

• Due to their consistent water flow and frequent rainfall, these areas have the greatest potential for hydro-electric power in the country.

Tribes

• 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
•  

General alignment

• From the north to the south direction. They are known by different local names.

Hills-

• These are low hills, inhabited by numerous tribal groups practising Jhum cultivation

• In the north, they are known as Patkai Bum, Naga hills, the Manipur Loktak Lake hills and

• In the south as Mizo or Lushai hills. Most of these ranges are separated from each other by numerous small rivers.

Loktak lake-

• The topography of Manipur is distinguished by the existence of a sizable lake named the "Loktak" lake, situated in the middle, and encompassed by mountains on all sides.

Molassis basin-

• Mizoram, a state in northeastern India, has been referred to as the "Molassis basin" due to its geological composition of soft and unconsolidated deposits.

Rivers-

• The Barak River holds significant importance in Manipur and Mizoram.
• The majority of rivers in Nagaland serve as tributaries of the Brahmaputra River.
• Two rivers in Mizoram and Manipur act as tributaries of the Barak River.
• The Barak River, in turn, acts as a tributary of the Meghna River.
• The eastern rivers in Manipur are tributaries of the Chindwin River.
• The Chindwin River, in turn, acts as a tributary of the Irrawady River in Myanmar.