Structure, relief and physiographic divisions

 

Three Geological divisions:

1. The peninsular block
2. The Himalayas and other Peninsular Mountains
3. Indo-Ganga-Brahmaputra Plain

 

• Peninsualar block is made of gneisses (metamorphic) and granites (igneous).

Six physiographic divisions:

1. The Northern and North-eastern Mountains
2. The Northern Plain
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands

Northern and North-Eastern Mountains

Approximate length of the Great Himalayan range: 2500 KM. Width: 160-400 KM

Impact of Himalayas on the Climate-of-india/”>Climate of India?

It can be divided into five sub-divisions:

1. Kashmir (or Northwestern) Himalayas
2. Himachal and Uttaranchal Himalayas
3. Darjeeling and Sikkim Himalayas
4. Arunachal Himalayas
5. Eastern Hills and Mountains

Kashmir Himalayas

• Ranges: Karakoram, Ladhakh, Zaskar, Pir Pinjal
• Glaciers: Baltoro, Siachen
• Passes: Zoji La (Great Himalayas), Banihal (Pir Pinjal), Photu La (Zaskar) and Khardung La (Ladakh)
• Lakes: (freshwater) Dal and Wular; (saltwater) Pangong Tso and Tso Moriri
• Pilgrimage: Vaishno Devi, Amarnath cave, Charar-e-Sharif
• They are also famous for Karewa formations which are useful for the cultivation of Zafran (a local variety of Saffron). Karewas are the thick deposits of glacial clay and other materials embedded with moraines.
• Kashmir is located on the banks of Jhelum river.
• Meanders is a typical feature associated with the rivers in this region.
• In South, there are longitudinal valleys called duns; Jammu dun and Pathankot dun

 

Himachal and Uttarakhand Himalayas

• Lies between rivers Ravi and Kali
• Drained by two major river systems: Indus and Ganga
• Northernmost part is an extension of the Ladakh desert, lies in Spiti.
• Ranges: Great Himalayan Range, Lesser Himalayas (Dhaoladhar in HP and Nagtibha in Uttarakhand), Shivalik range
• Pilgrimage: Gangotri, Yamunotri, Kedarnath, Badrinath, Hemkund Sahib and the five famous prayags (Refer to Panch Prayag)
• Famous for hill stations: Dharamshala, Mussoorie, Shimla, Kaosani; Cantt.: Kasauli, Almora, Lansdowne, Ranikhet
• The important distinguishing features of this area are the ‘Shivalik’ and ‘Dun formations’.
• Important duns: Chandigarh-Kalka, Nalagarh, Dehra, Harike, Kota
• Dehradun is the largest of all duns: Length – 35-45 KM, Width: 22-25 KM
• Inhabited with the Bhotia They migrate to higher reaches (Bugyals) in summer and return to the valleys during winters.

 

Darjeeling and Sikkim Himalayas

• Between Nepal Himalayas and Bhutan Himalayas.
• Fast flowing rivers such as Tista
• Peaks: Kanchenjunga
• Tribe: Lepcha
• Has a mixed Population of Nepalis, Bengalis and tribals from Central India.
• Importance: Due to the moderate slope, it is best suited for tea plantations. <India produces about 26 pc of tea in the world; second after China. Also, accounts for 12 pc of tea exports; fourth in the world.>
• Duar formations are peculiar to this region.

 

Arunachal Himalayas

• From Bhutan Himalayas to Diphu pass in the east.
• Direction: Southwest to Northeast
• Peaks: Kangtu and Namya Barwa
• Rivers: Brahmaputra, Kameng, Subansiri, Dihang, Dibang and Lohit.
• These rivers are perennial and have the highest hydro-electric power potential in the country.
• Tribes: Monpa, Daffla, Abor, Mishmi, Nishi and Nagas
• These communities practice shifting cultivation known as Jhumming.

 

Eastern Hills and Mountains

• Direction: North to South
• Ranges: Patkai Bum, Naga hills, Manipur hills, Mizo or Lushai hills
• These are low hills
• Tribes practice Jhum cultivation
• Rivers: Barak. Most of the Nagaland rivers form a tributary of Brahmaputra. Rivers in eastern Manipur are the tributaries of Chindwin, which in turn is a tributary of the Irrawady of Myanmar.
• Lake: Loktak
• Loktak Lake: is an important lake in Manipur which is surrounded by mountains on all sides. It is the largest freshwater lake in northeastern India. Also called the only Floating Lake in the world due to floating masses of organic matter on it. It serves as a source for hydropower generation, Irrigation and drinking water supply.
• Keibul Kamjao National Park located in the Bishnupur district of Manipur is the only floating park in the world and is an integral part of the Loktak Lake. Home to the endangered Manipur Eld’s Deer or Brow-antlered Deer or Sangai or Dancing Deer.
• Mizoram is also known as the ‘Molassis basin’ which is made up of soft unconsolidated deposits.

The Northern Plains

• Formed by the alluvial deposits of rivers – Indus, Ganga and Brahmaputra.
• Length: 3200 KM; Width: 150-300 KM

Three main zones:

1. Bhabar
2. Tarai
3. Alluvial Plains (Khadar and Bangar)

Bhabar

• Narrow belt. 8-10 KM wide.
• Paralllel to Shivalik at the break-up of the slope. Hence, streams and rivers deposit heavy rocks (and at times disappear) in this zone.

Tarai

• South of Bhabar. 10-20 KM wide.
• Rivers re-emerge and create marshy and swampy conditions known as Tarai.

Alluvial Belt

• South of Tarai.
• Features of mature stage of fluvial erosional and depositional Landforms such as sand bars, meanders, ox-bow lakes and braided channels. Riverine islands in Brahmaputra.
• Brahmaputra takes a turn an almost 90 degree turn at Dhubri (Assam) before entering Bangladesh.

 

Peninsular Plateau

• Bounded by the Delhi ridge, Rajmahal Hills, Gir range and Cardamom hills.
• Made up of a series of patland plateaus: Hazaribagh, Palamu, Ranchi, Malwa, Coimbatore, Karnataka etc.
• One of the oldest and most stable landmass of India.
• Physiographic Features: Tors, Block Mountains, rift valleys, spurs, bare rocky structures, hummocky hills and quartzite dykes offering natural sites for water storage.
• Black Soil in western and northwestern parts.
• Bhima fault in this region has frequent seismic activity (Lathur earthquake)
• NW part also has ravines and gorges: Chambal, Bhind and Morena.

Three broad regions:

1. Deccan Plateau
2. Central Highlands
3. Northwestern Plateau

Deccan Plateau

• Bordered by Eastern Ghats, Satpura, Maikal range and Mahadeo hills
• Important ranges: WG: Sahyadri, Nilgiri, Anaimalai and Caradamom hills; EG: Javadi hills, Palconda range, Nallamala Hills, Mahendragiri hills
• EG and WG meet at Nilgiri hills.
• Highest peak: Anaimudi (2695 m) on Anaimalai hills; Dodabetta (2637 m) on Nilgiri hills.
• Rivers: Mahanadi, Godavari, Krishna, Kaveri etc.

Central Highlands

• Bounded by the Aravali and Satpura range.
• Relic mountains, highly denuded and form discontinuous ranges.
• Near Jaisalmer it is covered by the longitudinal sand ridges and crescent-shaped sand dunes called barchans.
• Elevation: 700-1000 m
• Banas, a tributary of Chambal, originates in the Aravalli. Other tributaries of Yamuna originate from the Vindhyan and Kaimur ranges.
• Minerals in Chotanagpur plateau.

 

Northeastern Plateau

• Extension of the main Peninsular plateau.
• Meghalaya and Karbi Anglong plateau.
• Megahalaya plateau: Garo hills, Khasi hills and Jaintia hills (named after the tribals inhabiting the region)
• Rich in minerals like coal, iron, sillimanite, limestone and uranium.
• Receives maximum rainfall from SW monsoon. Hence, Meghalaya plateau has a highly eroded surface. Cherrapuni and Myswarnam.

 

Indian Desert

• Aka Marusthali
• Northwest of the Aravali hills
• Dotted with longitudinal dunes and barchans.
• Low rainfall: >150 mm per year Low vegetation cover
• Evidence that this area was under the sea during the Mesozoic era.
• Features: Mushroom Rocks, shifting dunes and oasis.
• Rivers are ephemeral: Luni. Brackish lakes. Inland drainage.

 

Coastal Plains

Two divisions:

1. Western coastal plains
2. Eastern Coastal Plains

Western Coastal Plains

• Submerged coastal plain. Hence, a narrow belt. Narrow in middle and broader towards north and south.
• Ports: Provides natural conditions for the development of ports and harbours due to submergence. Kandla, Mazagaon (Mumbai), JLN port Navha Sheva, Maramagao, Mangalore, Cochin etc.
• Mumbai has the world’s largest natural harbour.
• May be divided into: Kachchh and Kathiawar coast in Gujarat, Konkan coast, Goan coast and Malabar coast.
• Rivers don’t form delta.
• Kayals (Backwaters): Found in the Malabar coast. Used for fishing and inland navigation. Every year Nehru Trophy Vallamkali (boat race) is held in Punnamada Kayal in Kerala.

 

Eastern Coastal Plains

• Broader
• Emergent coast. Hence, less number of ports and harbours. Chennai, Vizag, Paradwip, Haldia.
• Delta formation

The Islands

Two major Divisions:

1. Andaman and Nicobar
2. Lakshwadeep & Minicoy

 

Andaman and Nicobar

• Two major island groups: Ritchie’s archipelago and the Labrynth island.
• The group is divided into: Andaman in the North and Nicobar in the South.
• Andaman and Nicobar separated by the Ten Degree channel.
• Barren Island
• Peaks: Saddle Peak (N.Andaman – 738 m), Mt. Diavolo (Middle Andaman – 515 m), Mt. Koyob (S Andaman – 460 m) and Mt. Thuiller (Great Nicobar – 642 m)
• Coral deposits found
• Convectional rainfalls and equatorial type of vegetation.

Lakshadweep and Minicoy

• Entire group built of coral deposits.
• Total of 36 islands of which 11 are inhabited.
• Smallest UT
• Minicoy is the largest island
• Separated by the 9 Degree Channel, north of which is the Amini Island and to the south Canannore island.
• These islands have storm beaches consisting of unconsolidated pebbles, shingles, cobbles and boulders.

,

The Earth’s surface is a complex and ever-changing landscape. The structure, relief, and physiographic divisions of the Earth’s surface are all determined by a variety of factors, including the movement of tectonic plates, the weathering and erosion of landforms, and the deposition of sediment.

The Earth’s crust is made up of a number of tectonic plates. These plates are constantly moving, and this movement causes the Earth’s surface to change. The plates can move together, apart, or collide. When plates move together, they can either push up mountains or create subduction zones. When plates move apart, they can create new ocean basins. When plates collide, they can either create mountains or form Volcanoes-2/”>Volcanoes.

The relief of the Earth’s surface is determined by the height and shape of the land. The land can be flat, hilly, or mountainous. The flattest parts of the Earth’s surface are the Oceans. The landmasses are much more hilly and mountainous. The highest mountains on Earth are the Himalayas, which are located in Asia.

The physiographic divisions of the Earth’s surface are determined by the way in which the land is grouped together. The land can be grouped into continents, oceans, and other landforms. The continents are the largest landmasses on Earth. The oceans are the largest bodies of water on Earth. Other landforms include islands, peninsulas, and plateaus.

The Earth’s surface is constantly changing due to the movement of tectonic plates, the weathering and erosion of landforms, and the deposition of sediment. These changes can be slow and gradual, or they can be sudden and catastrophic. The Earth’s surface is a dynamic and ever-changing landscape, and it is constantly being shaped by the forces of nature.

The Earth’s surface is divided into seven continents: Africa, Antarctica, Asia, Australia, Europe, North America, and South America. The continents are the largest landmasses on Earth, and they are separated by the oceans. The continents are home to a wide variety of Plants and animals, and they have been shaped by the forces of nature over millions of years.

The Earth’s surface is also divided into five oceans: the Arctic Ocean, the Atlantic Ocean, the Indian Ocean, the Pacific Ocean, and the Southern Ocean. The oceans are the largest bodies of water on Earth, and they cover about 71% of the Earth’s surface. The oceans are home to a wide variety of plants and animals, and they play an important role in the Earth’s climate system.

The Earth’s surface is a complex and ever-changing landscape. It is divided into continents, oceans, and other landforms. The Earth’s surface is constantly being shaped by the forces of nature, and it is a dynamic and ever-changing Environment.

Here are some frequently asked questions about the Earth’s structure, relief, and physiographic divisions:

• What is the Earth’s structure?
  The Earth’s structure is divided into four main layers: the crust, the mantle, the outer core, and the inner core. The crust is the outermost layer and is made of solid rock. The mantle is the next layer down and is made of molten rock. The outer core is the next layer down and is made of liquid iron. The inner core is the innermost layer and is made of solid iron.

• What is the Earth’s relief?
  The Earth’s relief is the variation in elevation of the Earth’s surface. The Earth’s relief is caused by the movement of tectonic plates. Tectonic plates are large pieces of the Earth’s crust that move around on the Earth’s surface. The movement of tectonic plates causes the Earth’s surface to rise and fall, creating mountains, valleys, and other landforms.

• What are the Earth’s physiographic divisions?
  The Earth’s physiographic divisions are the major landforms on the Earth’s surface. The Earth’s physiographic divisions are the continents, the oceans, the islands, and the polar regions. The continents are the large landmasses on the Earth’s surface. The oceans are the large bodies of water on the Earth’s surface. The islands are the smaller landmasses that are surrounded by water. The polar regions are the coldest regions on the Earth’s surface.

Here are some short answers to the questions above:

• The Earth’s structure is divided into four main layers: the crust, the mantle, the outer core, and the inner core.
• The Earth’s relief is the variation in elevation of the Earth’s surface.
• The Earth’s physiographic divisions are the major landforms on the Earth’s surface.

Sure, here are some MCQs without mentioning the topic Structure, relief and physiographic divisions:

1. Which of the following is the largest continent in the world?
   (A) Asia
   (B) Africa
   (C) North America
   (D) South America

2. Which of the following is the largest ocean in the world?
   (A) Pacific Ocean
   (B) Atlantic Ocean
   (C) Indian Ocean
   (D) Arctic Ocean

3. Which of the following is the highest mountain in the world?
   (A) Mount Everest
   (B) K2
   (C) Kangchenjunga
   (D) Lhotse

4. Which of the following is the longest river in the world?
   (A) Nile River
   (B) Amazon River
   (C) Yangtze River
   (D) Mississippi River

5. Which of the following is the largest desert in the world?
   (A) Sahara Desert
   (B) Arabian Desert
   (C) Gobi Desert
   (D) Atacama Desert

6. Which of the following is the largest rainforest in the world?
   (A) Amazon rainforest
   (B) Congo rainforest
   (C) Indonesian rainforest
   (D) Malaysian rainforest

7. Which of the following is the largest island in the world?
   (A) Greenland
   (B) New Guinea
   (C) Borneo
   (D) Madagascar

8. Which of the following is the largest lake in the world?
   (A) Caspian Sea
   (B) Lake Superior
   (C) Lake Victoria
   (D) Lake Baikal

9. Which of the following is the largest city in the world?
   (A) Tokyo
   (B) Delhi
   (C) Shanghai
   (D) Mexico City

10. Which of the following is the most populous country in the world?
    (A) China
    (B) India
    (C) United States
    (D) Indonesia

I hope these questions were helpful!