Major relief features of the world

social grade 6

1. Mountains are regions of Earth’s surface that are higher than surrounding areas. Long and continuous mountain ranges are called mountain chains. Group of mountain chains are called mountain systems. All mountains have pointed shapes called mountain peaks.

2. Mountains are of three types Fold mountains Volcanic mountains Block mountains

3. FOLD MOUNTAINS

4. Fold mountains are formed due to compression of horizontal layers of rocks. A simple fold mountain has a down fold or valleys called synclines and up folds or ridges called anticlines. Fold mountain are again divided into Young fold mountains Old fold mountains

5. V olcanic mountains

6. V olcanic mountains are formed by deposition of molten material called lava from beneath the crust. The molten material gradually piles up and coools layer after layer over the years to form a conical mountain. Mount fuji , Mount Kilimanjaro https://www.youtube.com/watch?v=iE6vplrtEO8

7. SIGNIFICANCE OF MOUNTAINS. Sources of rivers that bring alluvial deposits and helps in generating hydro elecrticity . Provides timber and other products. Provide habitat to wildlife. Act as climate barriers.

8. Plateaus

9. Plateaus are often caused by internal forces, volcanic eruption or erosion. They are elevated regions, lower than mountains, which have aflat top and steep sides. So Plateaus are called table lands. Plateau of Tibet is the highest Plateau in the world.

10. Significance of Plateaus Rich in minerals Rich in black soil

11. PLAINS

12. A plain is a low lying area, flat land not more than 200m above sea level. most plain are formed by the deposition of materials washed down from mountains and plateaus by rivers. These materials include silt, sand and clay, are called alluvium. So these plains are called alluvial plains. Eg ) Indo Gangetic plain, nile basin of Egypt

13. SIGNIFICANCE OF PLAINS They are fertile, encouraging agricultural practices of different types. Most large cities are situated in plains. Easy to develop roads, railways and canal system for cheap transport.