Geomorphology of the Indian sub-continent | Geology Optional for UPSC PDF Download

Geomorphology of India

Geomorphic Diversity of India

• India, a vast land, showcases unique geomorphic diversity and stunning landscapes.

Geographic Features

• India is an independent geographic entity, known as the Indian subcontinent.
• The country boasts various geomorphic features like snow-clad folded mountains in the north, plateaus, uplands, and plains.
• Narrow coastal plains line the coastal areas of India.

Formation of Geomorphic Features

• Distinct landforms and landscapes in India are shaped by internal (e.g., volcanic) and external (e.g., glacial, fluvial, aeolian, coastal, lacustrine, karst) geomorphic activities.

Geomorphic Processes in India

• Glacial processes are active in the higher Himalayan regions.
• Aeolian processes dominate the Thar Desert in western India.
• Fluvial processes occur across the country.
• Marine processes shape the eastern and western coastal regions of India.

Geomorphology

Definition

• Geomorphology is the study of the Earth's landforms, their processes, and the factors that shape them.

Impact Craters on the Moon

• Impact craters on the Moon are formed by the collision of celestial bodies such as asteroids or comets with the Moon's surface.
• These craters can vary in size and shape, with some showing distinct features like central peaks and terraced walls.

Dunes on Mars

• Dunes observed in the North polar region of Mars at specific coordinates are formed by wind-driven processes.
• These dunes provide insights into the atmospheric conditions and geological history of the planet.

Layered Rocks on Mars

• Layered rocks within Schiaparelli Crater on Mars reveal the geological history and environmental changes on the planet.
• Studying these rocks helps scientists understand past climates and the presence of water on Mars.

Landforms of India

Formation and Evolution

• The landforms of India have been shaped over millions of years by significant tectonic events and geological processes.
• Two main tectonic events:
  1. The breakup of India from Gondwana during the Jurassic period (170 million years ago).
  2. The collision of India with Asia during the Eocene (55 million years ago).
• Volcanic eruptions from the Reunion mantle plumes during the Upper Cretaceous era led to the formation of the Deccan plateau in peninsular India.
• The collision between India and Asia produced the Himalayas, the world's youngest and highest fold mountain belt.

Major Geomorphic Divisions of India

• India exhibits a wide array of landforms resulting from geomorphological processes, tectonic activities, volcanic eruptions, climatic conditions, and rock types.

Notable Landforms of India

• Deccan Traps: One of the largest igneous provinces in the world.
• Barren Island: The only active volcano in the Andaman and Nicobar Islands.
• Great Rann of Kachchh: A vast saline playa in Gujarat.
• Thar Desert: Home to various types of sand dunes.
• Estuaries and Deltas: Found along the eastern coast of India.
• Western Ghats: One of the great escarpments of the world.
• Kaimur Scarp: Located in the Vindhyan range.
• Megafans: Formed by the rivers Kosi and Gandak.
• Glacial Valleys and Lakes: Abundant in the Himalayas.
• Gulf of Kachchh and Khambhat: Home to large tidal mudflats.
• Granite Landforms: Such as those in Hampi, Karnataka.
• Volcanic Plug: Found in Mount Girnar, Gujarat.
• Lagoons: Examples include Chilika in Odisha and Pulicat in Andhra Pradesh.
• Coral Reefs: Found in Lakshadweep with central lagoons.
• Backwaters: Characteristic of the Malabar Coast.
• Mangrove Swamps: Present in various locations across India.
• Brahmaputra River: Known for its highly braided nature in Assam plains and the riverine island of Majuli.
• Ganga and Brahmaputra Plains: Vast alluvial plains in the Indo-Gangetic plain.
• Lonar Crater: A meteoritic impact crater in Maharashtra.

Basic Concepts of Geomorphology

Key Features

• Rift valleys like Narmada and Tapi.
• Picturesque gorges in the Himalayas, canyons along the Narmada River near Jabalpur, and the Kaveri Canyon.
• Waterfalls, gullies, ravines, and badland topography in regions like Siwalik Foothills, Yamuna-Chambal, and Chotanagpur zone.
• Distinct karst landforms like Borra and Belum caves in eastern India, Kutumsar caves in Chhattisgarh, Mawmluh caves in Meghalaya, and others.
• Additional attractions include Pachmarhi in Madhya Pradesh, Tapkeshwar in Dehradun, and Baratang and Middle Andaman in the Andaman and Nicobar Islands.

Self-Assessment Questions

1. Explain the disparity between landscape and landform.
2. Define the concept of relief in geomorphology.
3. List some prominent landforms in India that serve as major tourist destinations.
4. Describe the field of applied geomorphology and its significance.

Geomorphic Divisions of India

Himalayan Mountains System

• Stretching over 2500 km, it is one of the longest mountain chains globally.
• Features peaks like Mount Everest, Kanchenjunga, Dhaulagiri, and Nanga Parbat.
• Runs from Pamir in the west to Mishmi Hills in the east, forming an arc shape with a width of 150 to 400 km.

Indian Peninsula

• Exhibits a diverse range of geomorphic features and distinct geologic attributes.

Indo-Gangetic Plains

• Comprising fertile plains, this region is vital for agriculture and supports significant population density.

Other Subdivisions

• Includes the Thar Desert, coastal regions, and various islands.

Unit 2: Geomorphology of India

Himalayan Region

• Processes include glacial, fluvial, fluvio-glacial, orographic, and monsoonal rainfall activities.
• Aeolian processes observed in areas like Ladakh.
• Primary river systems: Indus, Ganga, Brahmaputra.
• Features: Cirques, U-shaped valleys, moraines, glacial meltwater streams.

Indian Peninsula

• Enclosed by Vindhyan hills and the Satpura chain.
• Includes Precambrian cratons and mobile belts.
• The Deccan Plateau features basaltic rocks and fluvial erosion.

Indo-Gangetic Plain

• Formed by sediments from the Ganga and Brahmaputra rivers during the Holocene period.
• Features include alluvial fans, floodplains, channels, deltas, meandering rivers, ox-bow lakes.
• Two types of alluvial deposits:
  • Bhangar: Older deposits with clay and calcareous alluvium.
  • Khadar: Younger deposits with fine silt and clay.