Explanation: The Aravalli Range is a significant geological feature in India, particularly in the state of Rajasthan. It is one of the oldest mountain ranges in the world, with its formation dating back to the Proterozoic era, approximately 1.8 billion years ago. This makes the Aravalli Range an old fold mountain range, characterized by its ancient geological history and the folding of the Earth's crust that occurred during its formation.
The term "old fold mountain range" refers to mountains that were formed by the folding of the Earth's crust due to tectonic activity in the distant past. The Aravalli Range is a prime example of such a formation, where the Earth's crust was compressed and folded, leading to the creation of these mountains. This process is different from the formation of younger mountain ranges like the Himalayas, which were formed by the collision of tectonic plates in more recent geological times.
The Aravalli Range stretches from the northwest to the southeast across Rajasthan, extending into Gujarat and Haryana. It plays a crucial role in the geography and ecology of the region, acting as a natural barrier that influences the climate and water resources of Rajasthan. The range is also rich in mineral deposits, including marble, limestone, and copper, which have been mined for centuries.
Understanding the Aravalli Range is essential for comprehending the geological history of Rajasthan and its impact on the region's landscape and resources. The range's ancient formation and its role in shaping the geography of Rajasthan make it a key feature in the study of Indian geology and geography.
In contrast, the other options listed do not fit the criteria of being an old fold mountain range. The Nilgiris and the Eastern Ghats are part of the Western Ghats system and are much younger, formed by the collision of the Indian and Eurasian tectonic plates. The Himalayas, while a significant mountain range, are relatively young, having formed about 50 million years ago. Therefore, the Aravalli Range is the correct answer as it is the oldest and most ancient mountain range among the options provided.