UPSC CSE Prelims
Major Mountains Previous Year Questions (PYQs)

Detailed Explanation:

Correct Answer: ✅ Option 3 (Only Four)

The Andes Mountains, the world's longest continental mountain range, extend along the western edge of South America. Among the given countries, the Andes pass through Bolivia, Colombia, Ecuador, and Venezuela. They do not pass through Brazil or Paraguay.

✅ Statement I is Correct: The Andes pass through Bolivia and include the famous Altiplano Plateau.

❌ Statement II is Incorrect: Brazil lies mainly on the Brazilian Highlands (Brazilian Plateau), not in the Andes region.

✅ Statement III is Correct: In Colombia, the Andes split into three parallel mountain chains (Cordilleras).

✅ Statement IV is Correct: The Andes run through Ecuador from north to south.

❌ Statement V is Incorrect: Paraguay lies in the interior lowlands east of the Andes.

✅ Statement VI is Correct: The Venezuelan Andes (Cordillera de Mérida) form the northern extension of the Andes.

Short Notes: Andes Mountains

• Andes are the longest continental mountain range in the world.

• Length: approximately 7,000 km.

• Highest peak: Aconcagua (6,961 m) in Argentina.

• The Andes extend through Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina.

• The Altiplano Plateau lies mainly in Bolivia and Peru.

• Formed by the subduction of the Nazca Plate beneath the South American Plate.

• Rich in minerals such as copper, silver, and tin.

Detailed Explanation:

Answer: Option 2 — Only two

This question tests the correct matching of mountain ranges with their regions and types. Out of the four given rows, only two contain completely accurate information regarding the region, name, and type of mountain range.

❌ Row 1 – Incorrect: The Vosges are located in Europe (eastern France), not Central Asia, and they are block mountains, not fold mountains.

❌ Row 2 – Incorrect: The Alps are correctly placed in Europe, but they are fold mountains formed by the collision of the African and Eurasian plates, not block mountains.

✅ Row 3 – Correct: The Appalachian Mountains are located in North America and are old fold mountains formed during the Paleozoic era.

✅ Row 4 – Correct: The Andes are located in South America and are young fold mountains formed by the subduction of the Nazca Plate beneath the South American Plate.

📝 Short Notes: Mountain Types and Formation

• Young Fold Mountains: Himalayas, Alps, Andes, Rockies — formed during the Tertiary period (66-2.6 million years ago); characterized by high peaks, sharp ridges, and active tectonic activity.
• Old Fold Mountains: Appalachians, Urals, Aravallis — formed during Paleozoic or earlier eras; extensively eroded with rounded peaks and lower elevations.
• Vosges and Black Forest: Classic examples of block mountains in Europe, formed by the same faulting process that created the Rhine Rift Valley between them.
• Plate Tectonics and Mountains: Most major mountain ranges are associated with convergent plate boundaries (fold mountains) or divergent boundaries with rifting (block mountains).