Correct Option
The correct option is (c) 1 and 3 only.
Explanation
The Aravali range is a classic example of Old Fold Mountains. Unlike Young Fold Mountains (e.g., the Himalayas), which are tectonically active and rising, Old Fold Mountains have undergone extensive denudation over geological time scales, resulting in Relict or Residual Mountains.
Statement-wise Analysis
- Statement 1 is Correct: The Aravali range is one of the oldest fold mountain systems in the world. Its geological origin dates back to the Proterozoic era (Pre-Cambrian period), making it significantly older than the Himalayas.
- Statement 2 is Incorrect: The Aravali range has not grown in height due to recent deposition. Deposition is a process that typically fills low-lying areas (aggradation). Mountains grow primarily through tectonic uplift (endogenic forces). Conversely, the Aravalis have been subjected to degradation for millions of years, reducing their height.
- Statement 3 is Correct: Over millions of years, the Aravali range has been worn down by exogenic forces such as weathering and erosion. Consequently, they now exist as eroded stubs or "relict" mountains, significantly lower in elevation than their original structure.
Key Takeaway
Relict Mountains (or Mountains of Accumulation/Denudation) represent the remnants of ancient mountain systems that have been lowered and sculpted by prolonged erosion.