MOUNTAINS

PRERNA FOR IAS

MOUNTAINS

1. Fold Mountains

Fold mountains are the most common and highest type of mountains on Earth. They are formed when two tectonic plates collide, causing layers of sedimentary rocks to compress, bend, and fold over millions of years. This process creates long mountain chains with rugged peaks and deep valleys. Fold mountains are generally young and continue to rise due to tectonic activity. They play an important role in influencing climate, river systems, biodiversity, and human settlements. Many of the world’s highest peaks are found in fold mountains. Examples include the Himalayas in Asia, the Andes in South America, and the Alps in Europe.

2. Block Mountains

Block mountains are formed due to faulting in the Earth’s crust. When tectonic forces create fractures called faults, large blocks of rock may either rise or sink. The uplifted blocks form block mountains, while the depressed portions become rift valleys. These mountains generally have steep sides and relatively flat tops compared to fold mountains. Block mountains are important geological features that provide evidence of crustal movements and tectonic activity. They often contain valuable mineral deposits and support diverse ecosystems. Famous examples include the Black Forest Mountains in Germany, the Vosges Mountains in France, and the Sierra Nevada in North America.

3. Volcanic Mountains

Volcanic mountains are formed by the accumulation of lava, ash, and other volcanic materials around a volcanic vent. During volcanic eruptions, molten magma rises from beneath the Earth’s surface and cools after reaching the surface, gradually building a mountain. These mountains usually have a cone-shaped structure with a crater at the summit. Volcanic mountains are associated with plate boundaries and hotspots. They are important sources of fertile soil, geothermal energy, and mineral resources. However, active volcanoes can pose serious hazards to nearby populations. Examples include Mount Fuji in Japan, Mount Kilimanjaro in Tanzania, and Mount St. Helens in the USA.

4. Residual (Erosional) Mountains

Residual or erosional mountains are formed through the long-term process of weathering and erosion. Over millions of years, wind, water, temperature changes, and other natural forces wear away softer rocks, leaving behind harder and more resistant rock masses as mountains. Unlike fold or volcanic mountains, residual mountains are not created by tectonic uplift but by the gradual removal of surrounding material. These mountains are generally older and lower in height due to prolonged erosion. They provide valuable information about Earth’s geological history and landscape evolution. Examples include the Aravalli Range in India, the Nilgiri Hills, and the Highlands of Scotland.

Mnemonic: FBVR

F – Fold Mountains → Himalayas, Andes, Alps
B – Block Mountains → Black Forest, Vosges
V – Volcanic Mountains → Mount Fuji, Kilimanjaro, St. Helens
R – Residual Mountains → Aravalli Range, Nilgiri Hills

Easy Memory Trick: FBVR = Fold → Block → Volcanic → Residual.