According to geological history, which of the following Indian mountain ranges is considered the oldest?

Introduction / Context:
India has several important mountain ranges, each with a different geological age and structure. Competitive exams often ask which of these ranges is the oldest according to geological evidence. This tests basic understanding of the geological history of the Indian subcontinent and the relative ages of its main mountain systems. The Aravalli range is particularly significant as one of the oldest fold mountain systems in the world.

Given Data / Assumptions:

• The question asks which listed mountain range is the oldest from a geological point of view.
• The options are Nilgiris, Satpura Range, Vindhyas, and Aravalli.
• We assume standard textbook information about geological ages of these mountain systems.
• Oldest here is interpreted in terms of formation age of the rocks and original folding, not current height or appearance.

Concept / Approach:
The core concept is geological time. The Aravalli range in northwestern India is recognised as one of the most ancient fold mountain ranges, with parts dating back to the Precambrian era. The Vindhyas and Satpuras are younger, largely formed during later geological periods. The Nilgiris in southern India are associated with the Western Ghats and are also comparatively younger in age. Therefore, by comparing the known geological ages of the ranges, one can identify which is the oldest.

Step-by-Step Solution:
Step 1: Recall that the Aravalli range extends roughly from Delhi through Rajasthan to Gujarat and is widely described as one of the world's oldest fold mountain systems.Step 2: Remember that the Vindhya range runs roughly east west across central India and is geologically younger than the Aravallis.Step 3: Note that the Satpura range lies just south of the Vindhyas and was formed later, with different tectonic processes.Step 4: Recognise that the Nilgiris form part of the junction region of the Western and Eastern Ghats in the south and are not as ancient as the Aravallis in geological terms.Step 5: From these comparisons, conclude that the Aravalli range is the oldest among the options.

Verification / Alternative check:
One quick cross check is to recall common textbook statements such as "The Aravalli range is one of the oldest fold mountains in the world." This phrase is repeated in many school books and exam guides. In contrast, the Vindhya and Satpura ranges are usually discussed as younger block or residual mountains that rose after the formation of the Deccan plateau. The Nilgiris are introduced mainly in the context of the Western Ghats and do not carry the label of being among the world's oldest mountains. This difference in how they are described confirms that Aravalli is the correct answer.

Why Other Options Are Wrong:
Nilgiris: These mountains are important but geologically much younger than the Aravallis, and they are not described as among the oldest fold mountains.
Satpura Range: The Satpuras are central Indian ranges formed later than the Aravallis and do not match the description of the very ancient Precambrian fold system.
Vindhyas: The Vindhya range is also younger than the Aravallis and mainly forms a structural feature separating the Indo Gangetic plains from the Deccan plateau.

Common Pitfalls:
Students often confuse "oldest" with "most eroded" or "less high" and may think that any low height range must be older. While erosion does reduce heights over time, reliable answers should be based on established geological age, not appearance alone. Another pitfall is mixing up the Vindhya and Aravalli ranges, since both are in northern or central India. A good way to avoid errors is to remember a simple fact: the Aravalli range is globally cited as one of the world's oldest fold mountains, making it clearly the correct choice here.

Final Answer:
According to geological history, the oldest mountain range among the options given is the Aravalli range.