The North and North Eastern Mountains of India

• It consist of
  • • Himalayas i.e. Northern Mountains of India
    • North eastern hills i.e. Purvanchal

Origin of the Himalayas or Northern Mountains of India

• The main theories about the origin of Himalayas are as under –

The Geosynclinal Origin

• • Main supporters of this theory are Argand, Kober and Seuss.

• • About 200 million years ago there was a supercontinent known as Pangaea and a super ocean known as Panthalsa.
  • Disintegration of Pangaea led to formation of two landmasses namely,
    • • Angaraland or Laurasia – Northern part consist of present day North America and Eurasia (Europe and Asia).
      • Gondwanaland- Southern part consist of present day South America Africa, South India, Australia and Antarctica.

• • Due to disintegration between Laurasia and Gondwanaland, water flows in and a long, narrow and shallow sea known as Tethys Sea was formed.
  • Sediments were brought by rivers from the landmasses and deposited on the bed of the Tethys Sea. These sediments assumed considerable thickness due to sinking nature of the sea bed.
  • Due to the southward movement of Angaraland or due to northward movement of the Gondwanaland, these sediments were subjected to heavy compression.
  • During Cretaceous period, Due to the continuous compression, the sediments got squeezed and series of folds formed one behind the other giving birth to Himalayas.
  • More importantly, the three ranges of the Himalayas were emerged out due to three different phrases followed one after another –
    • • First phase- (Eocene period) commenced about 65 million years ago and resulted in formation of Great Himalayas.
      • Second phase– (Miocene period) took place about 45 million years ago and Middle Himalayas were formed.
      • Third phase- (Pliocene Period) 1-2 million years ago and formed the Shiwaliks range of Himalaya.

Plate Tectonics Origin of Himalayas

• • Introduced by W.J. Morgan in 1967.
  • Based on the concept of Sea floor Spreading of H.H. Hess.
  • According to this theory, about 70-65 million years ago, there was extensive geosyncline called Tethys Sea In Place Of Himalaya.
  • About 60-30 million years ago the Indian plate came very closer to Asian plate and started subducting under Asian plate.

• • This causes lateral compression and due to which the sediments of Tethys Sea squeezed and folded into three parallel ranges of Himalayas.
  • Continent to continent collision of Indian and Asiatic plate started around 65 million years ago and caused Himalaya to rise from geosyncline Tethys.
  • Thus, the first major lift of Himalaya occurred in 65 million years ago which produced the Ladakh and Zaskar range of Trans Himalayan region before the formation of greater Himalayas.
  • The second major lift occurred around 45 million years ago, caused the rapid uplift of Southern mountain front of lesser Himalayas, giving rise to extremely rugged and beautiful and youthful Pir Panjal, Dhauladhar, Karol and Mahabharat ranges.
  • The greater Himalayas and lesser Himalayas are separated by Main Central Thrust.
  • The third uplift occurred around 1.4 million years ago between middle Miocene to middle Pliocene and resulted in the formation of Shiwalik.
  • The lesser Himalayas and Shiwalik are separated by Main Boundary Thrust.
  • The 5000 m shiwaliks dominated by boulders and Conglomerates reflects the progressive uplift of Himalayas.
  • The shiwaliks are separated from the northern plains of India by Himalayan Front Fault.
  • It has been estimated that this convergence has resulted in crustal shortening of about 500 km in Himalayan region and is compensated by sea floor spreading along the oceanic ridges in Indian Ocean region.
  • Since, the Indian plate is still moving North ward, height of Himalayan people still increasing.

Evidence to prove that Himalayas is still rising

• • • Fossil formation found in Shiwalik – similar fossils have been found in Tibetan plateau this indicates that in the past Tibetan plateau and Shiwalik hills shares a common location similar level and thus similar vegetation, climate, life etc. Than Tibetan plateau Got uplifted to present elevation.
    • Desiccation of lakes of Tibet – in Tibet plateau we find deposits that are found in lakes, this indicates that Lakes once existed in Tibet but because of upliftment the water got discharge and deposits remained there.
    • Frequent earthquake in region
    • Youthful nature of rivers – High erosion, V shaped valleys etc.
    • The present rate of upliftment of Himalayas has been calculated at 5 to 10 cm per year.

 

Characteristic Features of Himalaya

• Youngest Mountain Range- Himalayas are the youngest mountain range in the world. They are still rising at a pace of 5-10 cm a year.
• Arcuate Curve to the south the Himalayas form an arcuate curve which is convex to the south this curve shape of Himalaya is result of the maximum force exerted at the two ends on the Indian peninsula during its northward movement.
• Syntaxial bend the east west trend of the Himalayan is suddenly terminated at it Western and Eastern extremities and the Himalayan range take sharp southward bends these bends are called syntaxial bend of the Himalayas.
  • • • Western syntaxial bend – occurs near Naga Parvat where the Indus River has cut a deep gorge.
      • Eastern syntaxial bend – occurs at the eastern extremity of the Himalayas (Namcha Barwa) where the Himalayan range takes a sharp bend in the south direction.
• Varying width – Wider in West then in East due to the compressive forces which was more in East than in west. The Himalayas are wider in west, about 400 km wide in Kashmir and Nehru in East, about 150 km wide in Arunachal Pradesh.
• Topography- Ranges are separated by deep valleys creating a highly dissected topography.
• Slopes- the southern slopes of Himalaya facing India is steeper than the one facing the cavity inside which are generally gentler.
• Altitudinal Variation- The altitude variation in the eastern part is greater as compared to western parts.

Snowlines in Himalaya

• Snowlines – the lower limit of perpetual snow is called snowline. The snowline in Himalaya has different heights in different parts and depending on the latitude, altitude, amount of precipitation, moisture, slope and local topography.
• In Eastern Himalaya and Kumaon Himalaya, the snowlines around 3500 m above sea level whereas in western Himalayas snowlines about 2500 m above sea level.
• While the glacier of Kanchenjunga in Sikkim hardly moves below 4000 m and those of Kumaon and Lahul to 3600 m, the glacier of Kashmir Himalaya may descend to 2500 m above sea level.
• Difference in snowline is due to increase in latitude from 28o N in Kanchenjunga to 36o N in Karakoram.
• But the major factor is precipitation, precipitation in western Himalayas is comparatively low as compared to Eastern Himalayas and occurs as snowfall, where is in Eastern Himalaya precipitation is Greater and occurs in form of rain.
• In Greater Himalaya, snowline is at lower elevation on the southern slope then on Northern slope because southern slopes are steeper and receive more precipitation.

Glaciers in Himalaya

• • About 15000 glaciers in Himalaya.
  • Total area of Himalaya is above 500000 sq. km. About 33000 sq. km covered by snow.
  • The snowline varies in different part of Himalaya depending upon latitude, amount of precipitation and topography.

Glaciers of Karakoram Range

• • • Maximum development of glacier occurs in Karakoram Range.
    • Some of the largest glaciers outside the polar region are found in this range. Southern side of this range has maximum gigantic glaciers.
    • The 75 km long Siachen glacier in Nubra valley has the distinction of being the largest glacier outside the polar and sub polar region.
    • Second largest is the 74 km long Fedchenko glacier (Pamir).
    • Third largest is Hispar glacier 62 km long and occupies the tributary of Hispar River.

Glaciers Pir panjal

• • • They are less numerous and smaller in size as compared to those of Karakoram Range.
    • The longest Sonapani glacier in Chandra valley of Lahaul and Spiti region is only 15 km long.

Glaciers of the Kumaon Garhwal Region

• • • In Kumaon and Garhwal region of Himalaya the largest glacier is Gangotri glacier 30 km long source of river Ganga.
    • Second largest glacier Milam glacier occupies the valley of the Gori Ganga River. It is 20 km long.

Glaciers of Central Nepal

• • • Glaciers of this region are confined to the surrounding of Gosainthan, Manaslu, Annapurna and Dhaula Giri mountains.
    • The 13.5 km long Yepokangara glacier is in the Gosainthan Mountain.
    • Two 11 km long glaciers are in Lidanda and Chhuling glaciers both on south eastern side of Manaslu.

Glaciers of the Kanchenjunga Everest Region

• • • Rongbuk glacier is in the Northern side of the Mount Everest it is 52 km long.
    • Khumbu glacier 20 km lies south to the Mount Everest.
    • Zemu (25 km) and Kanchenjunga (21 km) are other major one.

Significance of Himalaya or Northern Mountains of India

1. 1. Influence on Indian climate

• • • They intercept the summer monsoon coming from Bay of Bengal and Arabian Sea causing precipitation in entire Ganga plain and North Eastern Hills.
    • Redirect the monsoon winds towards North Western India.
    • They protect Northern Plains from cold continental Air masses of Central Asia.
    • The Himalayas influence the path of subtropical jet stream flowing in the region. They split the jet stream and this split Jetstream plays an important role in bringing of Indian monsoon.
    • If there was no Himalaya, the whole of India would have been desert and its winters would have been very sever.

1. 2. Defence

• • • Natural defence barrier for India but Chinese aggression of 1962 has reduced the significance.

1. 3. Source of Rivers

• • • Rivers that feed nearly half a billion population of India originates from Himalaya.
    • The Himalayan River are perennial in nature and supply water all year around.
    • Most of the glaciers lies in the Himalaya.

1. 4. Fertile Soil

• • • The swift flowing river from Himalayas bring enormous amount of silt which constantly enrich the Ganga and Brahmaputra region.
    • This silt (alluvial soil) is very fertile in nature and helps in feeding the population.

1. 5. Hydroelectricity

• • • Due to its natural topography and Swift flowing natural perennial rivers, the Himalayan region offers several natural sites with great hydroelectricity power generation potential.
    • Many hydroelectricity power plants have already been constructed.

1. 6. Forest Wealth

• • • Due to its natural topography the Northern Mountains of India host rich coniferous evergreen forest. Lower levels have tropical evergreen forest and higher levels have alpine vegetation.
    • The Himalayan forest provides fuel wood and a large variety of timber for industries.
    • Himalayan forest most wide varieties of medicinal plants.
    • Several 50 are covered with grass offering rich postures for grazing.

1. 7. Agriculture

• • • Due to the rugged and sloped terrain, the Himalayas are not potential agricultural sites.
    • Some slopes are terraced for cultivation. Rice is the main crop on the terraced slope. Other crops are wheat maize potatoes etc.
    • Tea is a unique crop which can only be grown in Shiwalik hill region.
    • Fruit cultivation is major occupation. Wide variety of fruits such as apple, pear, grapes, mulberry, walnut, cherry, apricot etc. are also grown.

1. 8. Tourism

• • • Himalaya have a large number of tourist spot. The hilly area of Himalaya is not affected by hot winds like loo. Hence they offer cool and comfortable climate.
    • Dalhousie, Srinagar, Dharamshala, Shimla, Kullu, Manali, Nainital, Darjeeling etc. are important tourism centre cities.

1. 9. Cultural tourism

• • • Himalaya hosts many Hindu and Buddhist shrines.
    • Kailash, Amarnath, Badrinath, Kedarnath, Vaishno Devi, Gangotri, Yamunotri etc. all-important centres.

1. 10. Mineral deposits in Himalaya

• • • Geosynclinal deposits in tertiary rocks are regions of potential coal and oil reserves.
    • Coal is found in Kashmir, copper lead zinc gold silver limestone and precious and semi-precious stones occurs at some places in Himalaya.
    • But exploitation of these resources required at advanced technology which is not yet available.
    • Also disturbing such a fragile environment leads to more pain than gain.

So, this was all about The Northern Mountains of India – Origin, Features and Significance.

In the Next Post (Click Here), we are going to discuss The Northern Mountains of India – Physiographic and Regional Division.