Himalayas and Formation of India

Introduction

Understanding physiography means developing the knowledge about the collective behaviour of a country's climate, history & culture. In the previous chapters, we learned about the geographical extent of India and its frontiers. In this chapter, we will learn about the physical variations of the Indian Subcontinent and how the physiographic division of India, which includes the Himalayas, the Great Plains of North India, the Peninsular Plateau, the Coastal Plains and the major Islands are distributed.

Physiography of India

Physiography is the branch of geography that studies the present relief features of the Earth's surface. The relief features have been continuously shaped by both endogenetic and exogenetic forces across dierent geological periods. India secures a unique position across the world concerning its physiography. There are diverse landforms that spread across the vast dimension of the country, like the lofty young fold mountains, the flat plains, and the oldest plateaus of the world. Approximately 10.7% area is occupied by mountains, 18.5% by hills, 27.7% by plateaus and 43.2% by the plains. The north has a vast expanse of rugged topography consisting of a series of mountain ranges with varied peaks, beautiful valleys and deep gorges. The south consists of stable land with highly dissected plateaus, denuded rocks and developed series of scarps.In between these two lies the vast north Indian plain. However, the geological complexities pose a challenging task of dividing India into various physiographic regions. In general, India is divided into five physiographic divisions:

The Himalayas.
The Great Plains of North India.
The The Peninsular Plateau.
The Coastal Plains.
The Islands.

The internal and external forces resulting in changes in the earth's surface are called geomorphic processes. The geomorphic processes are broadly categorized into endogenic and exogenic forces based on their origin. The endogenetic forces are those forces that are coming from inside the earth. While exogenetic forces are drawing their power from the earth's exterior. In other words, these forces are present at or near the earth's surface.

The Himalayas

The Himalayan Mountains consist of The Himalayas (The Trans Himalayas, Himadri, Himavan, or Himachal and Shivaliks) and the Northeastern hills. The name "Himalaya" means "the abode of snow." The Himalayan Mountain system is the longest and highest young fold of mountains globally. The main Himalayas stretch 2400 kilometers from the Indus gorge to the Brahmaputra gorge in the east. The width of the Himalayas varies from 200 to 500 kilometers. The "Pamir knot" known as the roof of the world, connects the Himalayas with the mountain ranges of Central Asia. The Himalayas are considered to be the loftiest mountains in the world.

14 peaks have a height of more than 8000 meters, and 20 peaks have a height of more than7500 meters.

The Origin and Development of the Himalayas

The Continental Drift theory suggests that the continents were made from a single landmass. The landmass over the period separated to form seven continents that are present today. Around 200 Million years ago from the present, the single landmass that Principles of Indian Geography existed was named Pangea (Pan- All, Gea- Earth). The Pangea broke to form two landmasses named "Laurasia" in the North and "Gondwanaland" in the South. The "Tethys Sea" separated these two lands. The movement of both land masses approaching each other decreased their size. Later 40 to 50 Million years ago from the present, driven by plate movements, the Indian and Eurasian plates collided. The collision resulted in the sediments gathered in the Tethys Sea compressing, and several series of folds were formed. This is how the Himalayas were formed.

Evidence that proves that the Himalayas are rising:

Frequent Earthquakes: Frequent earthquakes reinforce the fact that there is continuous plate movement in the region, and the rise of the Himalayas still in progress.
Similar fossils in the Shivalik and Tibetan Plateau: Similar fossils are found in the Shivalik hills and Tibetan Plateau, thus confirming that in the past, the Tibetan plateau and Shivalik hills shared a common platform having similar altitude, vegetation, and life. Later the Himalayas got uplifted.
Youthful nature of rivers: The Youthful nature of rivers with high vertical erosion and v-shaped valleys confirms the downcutting of mountains by the rivers is in the process. It validates the fact that the Himalayas are still rising.

Division of Himalayas:

Geographically, the Himalayas are classified based on North to South divisions.

The Greater Himalayan Ranges, which includes:
- The Trans-Himalayas.
- The greater Himalayas or the Himadri.
The lesser Himalayas or the Himachal.
The Outer Himalayas or the Shiwalik.

Features of Himalayan Mountains

If one mindfully observes the shape of the Himalayas, one can find the Himalayas are forming an arcuate curve that is convex to the south. This curvature shape of the Himalayas is because of the maximum push oered at the two ends on the Indian Peninsula during the northward drift of the Indian plate. In the northwest direction, the push was offered by theAravallisand in the northeast, was pushed by the Assam ranges. This led to the formation of syntaxial bends at Nanga Parbat in the northwest and Namcha Barwa in the northeast. In the western syntaxial bend near Nanga Parbat, the Indus river has cut a deep gorge. The Brahmaputra cuts a deep gorge in the eastern syntaxial bend, called the Dihang gorge.
The mountain ranges are separated by deep valleys, gorges, and rivers. These physiographic features mark the youthful stage of the mountains and the rivers. As a result, an uneven and unsymmetrical topography is found in the region.
The Himalayas facing India are steeper than the Himalayas facing the Tibetan side. The Tibetan side of the Himalayas has gentler slopes and a gradual gradient.
The Himalayas can be seen wider in the west than in the east. The width of the mountain ranges varies from 400 kilometres in Kashmir to 150 kilometres in Arunachal Pradesh. The prime reason for the difference is the more significant compressive force in the east than in the west. This is the reason why high mountain peaks like Mount Everest and Kanchenjunga are present in Eastern Himalayas.
The Himadri and Himachal mountain ranges were formed before the formation of the Shivalik ranges. As the Fold Mountains of Himadri and Himachal were formed, the rivers rising from these ranges brought gravel, sand, and mud and deposited them in the shrinking Tethys Sea. As the plate movements caused folding, the freshly deposited sediments folded and gave rise to the loosely consolidated Shivalik Range.

The Great Himalayan Range

The great Himalayan Range can be divided into parallel running ranges, i.e., The Trans Himalayas, Great Himalayas or the Himadri, Lesser Himalayas, and the Shiwaliks.

Trans Himalayas

The Trans Himalayas are also known as Tibetan Himalayas. The mountain ranges lie to the immediate north of the Himadri or Great Himalayas in Jammu and Kashmir.
The major ranges of the Trans Himalayas are the Zaskar, the Ladakh, the Kailash, and the Karakoram.
The northernmost range of the Trans Himalayas is the Karakoram range, which has the biggest glaciers in the world outside the Polar Regions.
To the North of the Zaskar Range lies the Ladakh Range that runs parallel to it.
The Kailash range (Gangdise in Chinese) located in western Tibet is a part of the Ladakh Range.
While a few peaks span over 6000 meters, Mount Kailash stands as the highest peak (6714 m) in the range.
The Karakoram Range is the northernmost range of the Kailash Range and is also known as the Krishnagiri range.
The Karakoram Range extends 800 kilometers eastwards from the Pamirs and houses some of the greatest glaciers.
The elevation of the mountains is 5500 meters and above, while some of the peaks are more than 8000 meters above sea level. K2 or Godwin Austin or Qogir in the Karakoram Range is the second-highest mountain in the world and the highest peak in Indian Union.

Thrust Zones in the Himalayas

Indus-Tango Suture Zone is a belt of tectonic compression that is formed by the thrusting of the Indian plate against the Tibetan mass. It represents the boundary between the Indian and the Eurasian plates. This suture zone stretches from the North-Western Himalayan Syntaxis (Nanga Parbat) to the east till Namcha Barwa. The Karakoram Range and the Ladakh plateau lie to the North of the suture zone and are part of the European plate.
Main Central Thrust Zone separates the inner Himalayas in the north from the middle Himalayas to its south. This thrust zone played an essential role in the formation of these mountains.
Main Boundary Thrust is a reverse fault that extends from Assam to Punjab and serves to separate the outer Himalayas from the lesser Himalayas.
Himalayan Frontal Fault is a series of reverse faults that marks the boundary of the Shiwalik ranges of the Himalayan province from the alluvial expanse of the Indo-Gangetic plains.

The Great Himalayas or the Himadri

The Great Himalayas are also known as the inner Himalayas or Central Himalayas.
The Great Himalayas are the northernmost and the highest range of the Himalayas.
They are the most continuous mountain ranges in the world.
The mountain range terminates abruptly at the syntaxial bends:Nanga Parbat in the northwest and Namcha barwa in the northeast.
The mountains are made up of granite and have an average elevation of 6000 meters with an average width of 25 kilometers.
They are perennially covered with snow for their massive elevation.
All major prominent. Himalayan peaks are in this range, like Mt. Everest, Mr.Kanchenjunga, Mt. Nanga, Parbat, Mt. Namcha Barwa, etc. Major glaciers like the Siachen glacier, the Gangotri glacier, and the Yamunotri glaciers are located here.

The Shiwaliks or the Outer Himalayas

The Shiwalik is the southernmost range of the Himalayas and is also known as the outermost Himalayas. They are located between the Middle Himalayas and the Great Plains. In ancient times they were regarded as the Manak Parbat.
The altitude of these mountains ranges from 900-to 1100meters. The width varies from 50 kilometers in Himachal Pradesh to less than 15 kilometers in Arunachal Pradesh.
They are primarily composed of unconsolidated sediments brought down by rivers from the northern Himalayas. They form an nbroken chain of low hills except for a gap of 80-90kilometers formed by the valley of Teesta River and Raidak River.

With the rise of Shiwaliks, the rivers flowing were obstructed, and the lakes were formed. The debris brought by these rivers was deposited in these lakes. After the river's course was cut-off by the Shiwalik Ranges and lakes were drained away with due course of time, they left plains known as Duns in the west and Duars in the east.
They are shallow synclinal valleys in the northern end of the Shivalik Hills. They get confined to small parts of valleys like Dehradun, Kotlidun, Patlidun and Udhampur.
The Eastern part of the Shiwalik range extending up to Nepalis covered with thick forests, but the forest cover becomes thin in the west.
The southern slopes of this range are almost devoid of forest cover in Punjab and Himachal Pradesh and are highly frequented by seasonal streams.

Purvanchal or Eastern Hills

Eastern Hills or The Purvanchals are the southward extensions of the Himalayas running along the north-eastern edge of India.
At the Dihang gorge, the Himalayas take a sudden southward bend and form a series of comparatively low hills which are collectively called the Purvanchal.
Purvanchal hills are convex to the west.
They run along the India-Myanmar Border extending fromArunachal Pradesh in the north to Mizoram in the south.
Patkai Bum hills are made up of strong sandstone; elevation varying from 2,000 m to 3,000 m merges into Naga Hills where Saramati (3,826m) is the highest peak. Patkai Bum and Naga Hills form the watershed between India and Myanmar.
South of Naga Hills is the Manipur hills which are generally less than 2,500 meters in elevation.
The Barail range separates Naga Hills from Manipur Hills.
Further south the Barail Range swings to the west into Jaintia, Khasi, and Garo hills which are an eastward continuation of the Indian peninsular block. They are separated from the main block by Ganga and Brahmaputra rivers.
South of the Manipur Hills is the Mizo Hills (previously known as the Lushai hills) which have an elevation of less than 1,500 meters. The highest point is the Blue Mountain (2,157 m) in the south.

Longitudinal Divisions Of The Himalayas

Sir S. Burrad, divided the Himalayas longitudinally into 4 sub-divisions on the basis of river valleys which are as follows:

Kashmir Himalayas

The part of Himalayas lying between Indus and Sutlej known as Kashmir or Punjab Himalayas which stretches for 560 km. Himalayas acquired height gradually. It is the widest part of Himalayas with an extension of 250 to 400 km. This region is drained by the river Indus and its tributaries such as the Jhelum and the Chenab.
Jhelum in the valley of Kashmir is still in its youth stage and yet forms meanders - a typical feature associated with the mature stage in the evolution of fluvial landform.
It spread in the states of Kashmir and Himachal Pradesh which includes Zaskar, Ladakh, Karakoram. Pr Panjal and Dhauladhar ranges. Shimla is located in the Dhauladhar range.
The famous glaciers of South Asia like Siachen and Saltara,are located in this region. Fresh water lakes like Dal and Wular and salt water lakes like Pangong Iso and Tsu Moriri are found in this region.
Kashmir Himalayas are also famous for Karewas.

Kumaon Himalayas

It has wide area of 320 km between the Sutlej and Kali rivers in Uttarakhand. Its highest peak is Nanda Devi(7,817 m).
Its western part is known as Garhwal Himalays and the eastern part is known as Kumaon Himalayas. The altitude of Kumaon Himalayas is more as compared to the Punjab Himalayas.
Badrinath, Kedarnath, Trishul, Mana, Gangotri, Nanda Devi, Kamet etc. are its major peaks The origin place of most of the Ganga and Yamuna rivers i.e. Gangotri and Yamunotri numerous Glaciers are located in this range. Lakes like Nainital, Bhimtal and Sattal near Nainital (Uttarakhand) are located in this region. Passes like Mana and Niti are also located here.

Nepal Himalayas

It extends for 800 km between the Kali river and the Tista river, which is higher in altitude as compared to the Kumaon Himalayas. It is relatively small, but it is the most significant part of the Himalayas.
Its area is around 1,16,800 km'. This range is known as Sikkim Himalayas in Sikkim, Darieeling Himalayas in West Bengal and Bhutan Himalayas in Bhutan.
The highest peaks are Annapurna (8,073 m), Dhaulagiri 8,167 m), Gosaithan (8,013 m), Kancheniunga (8,598m), Cho Oyu (8,152 m), Makalu (8,470 m) and Mount Everest (8,848.86 m).

Assam Himalayas

It extends upto 720 km between Tista river and Brahmaputra river, which has less altitude as compared to the Nepal Himalayas. It is spread in the Indian states of Assam, Arunachal Pradesh, Sikkim and Bhutan.
Jomolhari and Jang Sargla, Kangtu, Kula Kangri, Pauhri, Namcha Barwa are the prominent peaks here, whereas Dibang-Dihang, Lohit, Kameng, Subansiri and Brahmaputra are the major rivers. The easternmost peak of the Himalaya is Namcha-Barwa (7,756 m). It is located on the boundary of Arunachal Pradesh and Tibet.
Jelep La, Bomdi La, Sela, Yangyap and Karpo La are the important passess of this region.

The Importance of Himalayan Region

Influence on Indian Climate: The Himalayan mountains influence Indian climate by standing across the path of the southwest monsoon winds and preventing them from escaping to the north. The moisture-laden winds collide with the mountain's southern slopes, resulting in orographic rainfall which is responsible for assisting India in growing a diverse range of crops.
The mountains also prevent cold winds from Central Asia from entering the Indian subcontinent, making the northern part of the country less cold and more comfortable in the winter.
Defence: Since time immemorial, the Himalayas have also provided protection and security from intruders. As a result, it acts as an important defence barrier. Despite the changing perception of modern warfare (aviation and cyber technology), the Himalayas' role as a defensive barrier cannot be overlooked.
Source of Rivers: The Himalayas also acts as a source of several rivers in India.Abundant rainfall, vast snowfields and huge glaciers are the feeding grounds of the mighty rivers of India. Melting snow during summer provides water to these rivers even during the dry season, and hence these are perennial rivers.
Hydroelectricity Potential: The Himalayan region also provides several sites that can be used for the production of hydroelectricity. Natural waterfalls can be found in some areas, and dams can be built across rivers in others. The recent investigations on the status of hydropower in the Hindukush Himalayan regions show that it has a hydroelectric potential of over 334 Gigawatts.
Forest Wealth: The Himalayan Mountains are abundant in forest resources. The Himalayan ranges exhibit a succession of vegetal cover from the tropic to the Alpine as they rise in elevation. The forests provide abundant wood used as fuel in industries and homes. The forest is also endowed with different kinds of trees, which act as raw materials for various industries that require timber, tree barks, and leaves as their raw materials. It is also important to note that several medicinal plants grow in the Himalayan regions. It serves as an essential source for herbal medicine, some of which the pharmaceutical industries manufacture can't manufacture. The forests here play a crucial role in providing shelter to various wild animals; the wild animals are important as they balance the ecosystem. The woods are also of agricultural significance as they oer vast pastures for grazing animals as several patches are covered with grass.
Agriculture: The fertile soils deposited by the Himalayan rivers have promoted agriculture in the plains. Several crops are grown and, in turn, provide food for the farmers. The crops grown are also a source of income, and, in turn, it contributes to India's economy. Some of the important crops grown include rice, wheat, ginger, maize, tobacco, potatoes etc. We can also find peaches, walnut, mulberries etc here.
Tourism: the Himalayas provide a huge tourism scope due to its scenic beauty and healthy environment. Several tourist spots are found in the Himalayas, such as Mussoorie, Shimla, Kulu, Manali, Nainital, Chamba, Ranikhet, Almora, Darjeeling, Mirik, Gangtok, etc. The interest in these spots is due to the calm and pleasant weather conditions and increasing craze for winter sports.
Pilgrimage: The Himalayas is studded with sanctified shrines which are said to be homes of the gods. They are home to several important pilgrimage Tibetan Plateau sites like Kailash, Amarnath, Badrinath, Kedarnath, Tungnath, Vaishnu Devi, Jwalaji, Uttarakashi, Gangotri, and Yamunotri.
Minerals: The Himalayas, as we know, are the result of sediments deposited by rivers in the Tethys Sea. Along with this deposition, thousands of fossils are buried, which exist today in the form of minerals. The Himalayan region contains many valuable minerals. The tertiary rocks are endowed with massive potential mineral oils. Other minerals such as copper, limestone gold, nickel, and silver, among others, are known to be abundant.