Which one of the following is the oldest mountain range in India ?

1. Major Physiographic Divisions of India (basic)

Welcome to your journey through the diverse landscape of India! To master the mountain ranges of our country, we must first understand the 'big picture'—the broad physical layout. **Physiography** is the study of the surface features and landforms of the Earth. India’s current physical form is the result of millions of years of geological processes, primarily the interplay between **endogenic forces** (internal movements like plate tectonics) and **exogenic forces** (external forces like erosion and weathering) INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Structure and Physiography, p.8.

Geologically, India is divided into three major blocks: the stable **Peninsular Block**, the young and restless **Himalayas**, and the vast **Indo-Ganga-Brahmaputra Plain**. However, for a more detailed study, we categorize the country into **six major physiographic divisions** CONTEMPORARY INDIA-I, Geography, Class IX (NCERT 2025 ed.), Physical Features of India, p.7:

• The Himalayan Mountains: Young, structurally fold mountains that act as a northern barrier.
• The Northern Plains: Formed by the alluvial deposits of the Indus, Ganga, and Brahmaputra rivers.
• The Peninsular Plateau: A tableland composed of old crystalline, igneous, and metamorphic rocks. It is the oldest part of the Indian landmass.
• The Indian Desert: The arid 'Thar' region characterized by sand dunes and low rainfall.
• The Coastal Plains: Narrow strips of land flanking the Peninsular Plateau along the Arabian Sea and Bay of Bengal.
• The Islands: The Lakshadweep and the Andaman & Nicobar groups.

Understanding the contrast between these regions is vital for UPSC. For example, while the Himalayas are high and rugged, the Peninsular Plateau is a highly eroded, stable landmass containing some of the oldest mountains in the world, such as the Aravallis Geography of India, Majid Husain (9th ed.), Physiography, p.54.

Feature	Himalayan Region	Peninsular Plateau
Geological Age	Young and recent	Ancient and stable (part of Gondwanaland)
Rock Type	Mostly Sedimentary	Igneous and Metamorphic
Topography	High peaks, deep valleys	Rounded hills, shallow valleys

Sources: INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Structure and Physiography, p.8; CONTEMPORARY INDIA-I, Geography, Class IX (NCERT 2025 ed.), Physical Features of India, p.7; Geography of India, Majid Husain (9th ed.), Physiography, p.54

2. Classification of Mountains: Fold, Block, and Relict (basic)

To master the geography of India, we must first understand the "blueprints" of how mountains are built. Mountains aren't just piles of rock; they are the result of massive tectonic forces acting over millions of years. Geologists primarily classify them into three types based on their origin and the forces that shaped them: Fold, Block, and Relict.

Fold Mountains are the most common type and are created when two tectonic plates collide, causing the Earth's crust to buckle and fold. We further divide these by age. Young Fold Mountains, like the Himalayas, are geologically recent, exceptionally high, and have rugged, pointed peaks CONTEMPORARY INDIA-I, Physical Features of India, p.7. In contrast, Old Fold Mountains, such as the Aravalli Range, were formed hundreds of millions of years ago. Because they have been exposed to the elements for so long, their peaks are rounded and their elevations are much lower Physical Geography by PMF IAS, Types of Mountains, p.135.

Block Mountains form when the Earth's crust cracks (faults) due to internal tension. Instead of folding, large blocks of the crust are pushed up or sink down. The uplifted blocks are called Horsts (the mountains), and the sunken blocks are Grabens (the valleys). In the Indian context, the Satpura and Vindhya ranges are classic examples of this landscape, where the land between them has often sunk to form rift valleys through which rivers like the Narmada flow Physical Geography by PMF IAS, Types of Mountains, p.132.

Relict (or Residual) Mountains are the "survivors" of the geological world. They aren't currently being pushed up by tectonics; rather, they are the remains of very old mountain systems that have been heavily eroded by wind, water, and ice over eons. The Aravallis are often called thickening relict fold mountains because while they started as fold mountains, today they exist as highly eroded ridges Physical Geography by PMF IAS, Types of Mountains, p.135.

Comparison of Mountain Types

Feature	Fold Mountains	Block Mountains	Relict Mountains
Primary Force	Compression (Pushing)	Tension/Faulting (Cracking)	Denudation (Erosion)
Appearance	Folded layers, ridges	Flat tops, steep sides	Rounded, low ridges
Indian Example	Himalayas (Young)	Satpura Range	Aravallis (Old)

Sources: CONTEMPORARY INDIA-I, Geography, Class IX . NCERT(Revised ed 2025), Physical Features of India, p.7; Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.), Types of Mountains, p.135; Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.), Types of Mountains, p.132

3. The Himalayan System: Young Fold Mountains (intermediate)

The Himalayas are the world's highest and most iconic example of Young Fold Mountains. To understand why they are called 'young,' we must look at the geological clock. While mountains like the Aravallis date back billions of years, the Himalayas began forming only about 65 million years ago — a mere 'yesterday' in geological terms! Their formation is the result of a massive tectonic collision between the Indian Plate (part of the ancient Gondwanaland) and the Eurasian Plate (Angaraland). As these two massive landmasses converged, the Tethys Sea that lay between them disappeared. The thick layers of marine sediments deposited on the sea floor were compressed and squeezed upward, folding like a giant rug to form the peaks we see today Geography of India, Majid Husain, Physiography, p.3.

This process of mountain building, known as orogeny, didn't happen all at once. It occurred in three distinct pulses or 'upheavals,' each creating a different parallel range within the Himalayan system. The first pulse pushed up the Greater Himalayas (Himadri), followed millions of years later by the Lesser Himalayas (Himachal), and finally the Shiwaliks (Outer Himalayas). Interestingly, the Main Central Thrust (MCT) acts as the major boundary separating the Greater and Lesser ranges Geography of India, Majid Husain, Physiography, p.8.

What makes the Himalayas truly 'young' and 'restless' is that they are still rising. Because the Indian Plate continues to move northward and push against Eurasia, the mountains grow by a few centimeters every year. This ongoing tectonic activity is the reason why the Himalayan region is so prone to frequent earthquakes. Unlike 'relict' or 'old' mountains that have been leveled down by millions of years of erosion, the Himalayas retain their high, jagged peaks and deep, V-shaped valleys, characteristic of a youthful stage Geography of India, Majid Husain, Geological Structure and formation of India, p.22.

Sources: Geography of India, Majid Husain, Physiography, p.3; Geography of India, Majid Husain, Physiography, p.8; Geography of India, Majid Husain, Geological Structure and formation of India, p.22

4. The Peninsular Plateau: Vindhyas and Satpuras (intermediate)

While the Himalayas represent the youthful energy of folding, the Vindhya and Satpura ranges tell a story of faulting and structural shifts. Geologically, these are classified as Block Mountains (or Horsts). They were formed when the earth's crust underwent intense tension, causing large blocks of land to rise or the surrounding land to subside, creating massive graben (rift valleys) in between Physical Geography by PMF IAS, Types of Mountains, p. 133. These ranges act as the great geographical divide of India, effectively separating the Indo-Gangetic Plains of the north from the Deccan Plateau of the south.

The Vindhyan Range is not a single continuous chain but a series of broken plateaus and escarpments. It stretches for about 1,050 km, starting from Jobat in Gujarat and extending all the way to Sasaram in Bihar Geography of India, Majid Husain, Physiography, p. 54. It forms a massive water divide; the rivers to its north (like the Chambal, Ken, and Betwa) flow toward the Yamuna/Ganga, while the Narmada flows immediately to its south. The eastern part of the Vindhyas includes the Kaimur Hills, while the Maikal Range acts as a physical bridge connecting the Vindhyas with the Satpuras Geography of India, Majid Husain, Physiography, p. 54.

Parallel to the Vindhyas lies the Satpura Range (meaning 'Seven Folds'). It is a complex system composed of the Rajpipla Hills in the west, the Mahadev Hills in the center, and the Maikal Range in the east Geography of India, Majid Husain, Physiography, p. 55. The Satpuras are higher and more rugged than the Vindhyas. The highest point of the entire range is Dhupgarh (1,350 m), located near the beautiful hill station of Pachmarhi in the Mahadev Hills. Another crucial peak is Amarkantak, which is the famous source of the Narmada and Son rivers Geography of India, Majid Husain, Physiography, p. 55.

Feature	Vindhya Range	Satpura Range
Location	North of the Narmada River	Between Narmada and Tapi Rivers
Highest Peak	Sadbhawana Shikhar (Goodwill Peak)	Dhupgarh (1,350 m)
Key Hills	Kaimur, Rewa, Bharner	Rajpipla, Mahadev, Maikal

The positioning of these ranges creates a unique Rift Valley system. The river Narmada flows in a narrow trough between the Vindhyas and Satpuras, while the Tapi river flows in a constricted rift valley south of the Satpuras, between the Satpuras and the Ajanta Range Geography of India, Majid Husain, The Drainage System of India, p. 20.

Sources: Physical Geography by PMF IAS, Types of Mountains, p.133; Geography of India, Majid Husain, Physiography, p.54-55; Geography of India, Majid Husain, The Drainage System of India, p.20

5. The Western Ghats and Nilgiri Hills (intermediate)

The Western Ghats, also known as the Sahyadris, are one of India’s most significant geographical features. Unlike the Himalayas, which are tectonic fold mountains, the Western Ghats are technically the faulted edge of the Deccan Plateau. Imagine the Indian peninsula as a giant tilted block; the Western Ghats represent the high, uplifted western rim of that block. They run parallel to the western coast for about 1,600 km, starting from the Tapi valley down to Kanyakumari INDIA PHYSICAL ENVIRONMENT, Geography Class XI, p.12.

One of the defining characteristics of the Western Ghats is their continuity. Unlike the Eastern Ghats, which are highly dissected by rivers, the Western Ghats can only be crossed through specific mountain passes (ghats) such as the Thal Ghat (connecting Mumbai to Nashik), the Bhor Ghat (connecting Mumbai to Pune), and the Palghat Gap CONTEMPORARY INDIA-I, Geography, Class IX, p.12. They also act as a massive climatic barrier, forcing moisture-laden monsoon winds to rise and shed heavy orographic rainfall on the western slopes, while the eastern side remains a rain-shadow area.

As we move south, the range becomes more complex. In the state of Tamil Nadu, the Western Ghats meet the Eastern Ghats to form a massive mountain knot known as the Nilgiri Hills (the 'Blue Mountains') Geography of India, Majid Husain, Chapter 2, p.58. South of the Nilgiris, separated by the Palghat Gap, the range continues as the Anaimalai Hills and the Cardamom Hills. It is here that we find Anaimudi (2,695 m), which is the highest peak in both the Western Ghats and the entire Peninsular India Geography of India, Majid Husain, Chapter 2, p.58.

Feature	Western Ghats	Eastern Ghats
Continuity	Continuous; crossed via passes.	Discontinuous; eroded by rivers.
Elevation	Higher (900–1600 m).	Lower (Average 600 m).
Rainfall	Heavy Orographic rain.	Less rainfall; parallel to monsoon.

Sources: Geography of India, Majid Husain, Physiography, p.58, 61; CONTEMPORARY INDIA-I, Geography, Class IX, Physical Features of India, p.12; INDIA PHYSICAL ENVIRONMENT, Geography Class XI, Structure and Physiography, p.12

6. Precambrian Shield and Ancient Rock Systems (exam-level)

To understand the geological backbone of India, we must look at the Precambrian Shield. Think of a 'shield' as the ancient, stable core of a continent that has remained tectonically calm for billions of years. In India, this is the Peninsular Plateau. The most ancient part of this shield is the Archaean System, often called the 'Basement Complex' or 'Fundamental Gneiss' because it forms the foundation upon which all later geological layers were built Geography of India, Geological Structure and formation of India, p.4. These rocks, including granite and gneiss, are unfossiliferous (containing no fossils) because they formed long before complex life appeared on Earth.

As these early Archaean rocks eroded, their debris settled and underwent intense heat and pressure to form the Dharwar System (approx. 2500 to 1800 million years ago). These are significant because they are the first metamorphosed sedimentary rock systems in India Geography of India, Geological Structure and formation of India, p.7. This system is the 'treasure house' of India's minerals, containing massive reserves of iron ore in the Singhbhum and Keonjhar regions, and copper in the Malanjkhand belt Geography of India, Geological Structure and formation of India, p.10.

The Aravalli Range stands as the most iconic representative of this ancient era. While we often think of mountains as tall and jagged like the Himalayas, the Aravallis are Relict Mountains. Formed during the Proterozoic Eon as majestic fold mountains, they have been ground down by hundreds of millions of years of wind and water. While the Himalayas are 'Young Fold Mountains' formed only 40–50 million years ago during the collision of the Indian and Eurasian plates Physical Geography by PMF IAS, Convergent Boundary, p.121, the Aravallis are among the oldest mountain systems in the world, stretching back over 2.5 billion years.

Feature	Precambrian Systems (e.g., Aravallis/Dharwar)	Tertiary Systems (e.g., Himalayas)
Age	Ancient (Billions of years old)	Young (Millions of years old)
Rock Type	Crystalline, Metamorphic (Gneiss, Schist)	Sedimentary and Metamorphosed Sediments
Nature	Relict/Residual (highly eroded)	Active/Tectonic (still rising)

Sources: Geography of India, Geological Structure and formation of India, p.4; Geography of India, Geological Structure and formation of India, p.7; Geography of India, Geological Structure and formation of India, p.10; Physical Geography by PMF IAS, Convergent Boundary, p.121

7. The Aravalli Range: The Oldest Orogenic Belt (exam-level)

The Aravalli Range is not just a collection of hills; it is a geological ancestor. Formed during the Proterozoic Eon, these mountains are among the oldest fold mountain systems in the world, with some formations estimated to be 2.5 billion years old Exploring Society: India and Beyond, Chapter 1: Geographical Diversity of India, p.14. While the Himalayas are "Young Fold Mountains" still rising today, the Aravallis are relict (or residual) mountains — the worn-down remnants of a once-towering range. Over eons, extensive denudation and erosion have scrubbed them down, leaving behind highly eroded ridges that stretch for about 800 km from Delhi, through Haryana and Rajasthan, to Palanpur in Gujarat Geography of India, Chapter 2: Physiography, p.54.

Geologically, the range is part of the Dharwar System, representing the first metamorphosed sedimentary rock systems in India. It is primarily composed of Precambrian rocks such as quartzites, gneisses, and schists Geography of India, Chapter: Geological Structure and formation of India, p.7. These hard, crystalline rocks are the reason the range still stands today despite billions of years of weathering. The highest point is Guru Shikhar (1,722 m) on Mount Abu. Interestingly, while the main range is fairly continuous, it is punctuated by passes like the Goran Ghat, which connects Udaipur with the districts of Sirohi and Jalore Geography of India, Chapter 2: Physiography, p.59.

Structurally, the Aravallis serve as a major transition zone. They are separated from the Vindhyan Mountains by a massive tectonic feature known as the Great Boundary Fault (GBF) Geography of India, Chapter 2: Physiography, p.54. Understanding this range is critical for UPSC because it acts as a climate barrier, checking the eastward spread of the Thar Desert and influencing the rainfall patterns of Northwest India.

Feature	Aravalli Range	Himalayan Range
Type	Old Fold (Relict) Mountains	Young Fold Mountains
Geological Age	Precambrian (~2.5 billion years)	Tertiary (~50 million years)
Rock Composition	Quartzites, Gneisses, Schists	Sedimentary rocks (mostly)

Sources: Exploring Society: India and Beyond, Chapter 1: Geographical Diversity of India, p.14; Geography of India, Chapter 2: Physiography, p.54, 59; Geography of India, Geological Structure and formation of India, p.7

8. Solving the Original PYQ (exam-level)

This question brings together your understanding of geological time scales and the physiographic divisions of India. While you have recently studied how the Indian plate collided with the Eurasian plate to create the Himalayas, this question asks you to look much further back into Earth's history to the Precambrian era. By applying the concept of orogeny (mountain building), you can see that the Aravali range represents the earliest orogenic belt in the Indian subcontinent. As highlighted in Geography of India, Majid Husain, these are classic Old Fold Mountains that have been transformed into relict mountains through eons of erosion.

To arrive at the correct answer, (B) Aravali, you must systematically eliminate the other options based on their chronological formation. A common trap for students is to choose the Himalayas because of their scale; however, geologically speaking, they are Young Fold Mountains formed only during the Tertiary period. While the Satpura and Nilgiri ranges are indeed ancient parts of the Peninsular Plateau, they do not predate the 2.5 billion-year-old formations found in the Aravalis. According to Physical Geography by PMF IAS, the Aravalis were already a weathered system by the time the other ranges even began to take shape.

In the UPSC context, it is crucial to distinguish between morphology (the physical appearance) and geological age. The Aravalis may appear as humble, highly eroded ridges today, but their rock composition of quartzites, gneisses, and schists reveals their ancient origin. As noted in Exploring Society: India and Beyond, NCERT, understanding this Geographical Diversity allows you to see the Aravalis not just as hills in Rajasthan, but as the foundational pillars of the Indian landmass. Always remember: the most prominent feature is rarely the oldest.