Correct Option
The correct option is 1 and 2.
[as per provisional answerkey]
Explanation
The Peninsular Block of India is one of the oldest and most stable landmasses on Earth, primarily composed of ancient gneisses and granites. Unlike the Himalayas, it is characterized by relict features, senile topography, and tectonic stability, though it has undergone vertical movements and fracturing.
- Statement 1 is Correct: The western coast of India has experienced submergence and emergence due to tectonic activity and eustatic changes in sea level. The Arabian Sea coast, particularly the Konkan and Malabar regions, shows evidence of submergence, which has resulted in the formation of natural harbors and the straight coastline of the Western Ghats.
- Statement 2 is Correct: The Peninsular Block is home to several residual or relict mountain ranges. These are the remnants of older mountain systems that have been subjected to prolonged denudation. Examples include the Veliconda hills (Andhra Pradesh), Mahendragiri hills (Odisha), Nallamala hills, and the Javadi hills.
- Statement 3 is Incorrect: Deep, V-shaped valleys are characteristic features of youthful river systems, typically found in the Himalayan region where rivers are fast-flowing and actively eroding vertically. In contrast, the rivers of the Peninsular Block are in a mature stage, characterized by broad, shallow valleys with low gradients and lateral erosion.
Key Takeaway: The Peninsular Block is defined by stable, ancient geological structures and mature topography (broad valleys and residual hills), whereas youthful features like V-shaped valleys are exclusive to the Himalayan mountain system.