Model Answer
0 min readIntroduction
The Deccan Plateau constitutes a large portion of the Indian Peninsula, covering approximately 40% of the country’s total area. Formed primarily from basaltic lava flows during the Cretaceous and early Tertiary periods, it’s a stable landmass exhibiting a diverse range of relief features. The plateau’s formation is linked to the Deccan Volcanic Province, a massive volcanic event that significantly altered the landscape. Understanding its structure and relief is vital for comprehending the region’s hydrology, soil characteristics, and overall ecological patterns.
Geological Structure and Formation
The Deccan Plateau is largely a volcanic formation, built up over millions of years by successive eruptions. The underlying structure consists of ancient crystalline rocks – Archaean and Proterozoic gneisses and granites – which form the basement. These are overlain by thick layers of basalt, ranging in thickness from 200 to 1500 meters. The basalt flows are interbedded with sedimentary layers like laterites and limestones, particularly towards the eastern and western margins.
The formation of the Deccan Plateau is attributed to the Reunion hotspot, a volcanic hotspot currently located near Réunion Island in the Indian Ocean. Around 66 million years ago, the Indian plate moved over this hotspot, resulting in massive volcanic eruptions that created the Deccan Traps – the extensive basaltic lava flows.
Relief Features
1. Lava Plateaus and Basaltic Plains
The most prominent relief feature is the extensive lava plateau, characterized by flat-topped mesas and undulating plains. These are formed by the accumulation of basaltic lava flows. The plateau’s surface is often covered by black cotton soil (regur), derived from the weathering of basalt. Examples include the Malwa Plateau and parts of the Maharashtra Plateau.
2. Residual Hills and Ranges
Erosion has dissected the lava plateau, leaving behind numerous residual hills and ranges. These are composed of harder rock formations that resisted erosion. Some prominent examples include:
- The Western Ghats: Forming the western edge of the plateau, these are steep, escarpment-like ranges formed by faulting and erosion.
- The Eastern Ghats: Less continuous and lower in elevation than the Western Ghats, these ranges are also formed by erosion and faulting.
- The Satpura Range: A horst (uplifted block) forming a significant barrier between the northern and southern parts of the plateau.
- The Maikal Range: A continuation of the Satpura range, located in Chhattisgarh.
- The Nilgiri Hills: A small, isolated range in the southern part of the plateau, known for its unique biodiversity.
3. River Valleys and Drainage Patterns
The Deccan Plateau is drained by several major rivers, including the Godavari, Krishna, Cauvery, and Narmada. These rivers have carved deep valleys and gorges through the plateau, creating a dendritic drainage pattern. The river valleys are fertile agricultural lands, supporting a large population.
Drainage Systems:
| River | Direction of Flow | Major Tributaries |
|---|---|---|
| Godavari | East | Pranita, Indravati, Penganga |
| Krishna | East | Tungabhadra, Koyna, Musi |
| Cauvery | East | Kabini, Bhavani, Amaravati |
| Narmada | West | Hiran, Tapti |
4. Plateaus and Terraces
Besides the main plateau, several smaller plateaus and terraces are found within the Deccan region. These are formed by differential erosion and faulting. Examples include the Chota Nagpur Plateau (though often considered separate, it shares geological similarities) and the Karnataka Plateau.
5. Black Soil Regions
Large areas of the Deccan Plateau are covered by black soil, also known as regur soil. This soil is highly fertile and ideal for cotton cultivation. It is formed from the weathering of basaltic lava and is rich in iron, lime, and magnesium.
Conclusion
The Deccan Plateau’s structure and relief are a testament to its long geological history and the powerful forces of volcanism and erosion. Its basaltic foundation, residual hills, and river-carved valleys create a unique landscape that supports diverse ecosystems and agricultural practices. Understanding the plateau’s geomorphology is crucial for sustainable resource management and mitigating natural hazards in this vital region of India. The continued study of the Deccan Traps provides valuable insights into Earth’s volcanic past and its impact on climate and life.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.