(a) Name three types of mountains and give a good example of each
(b) Describe the process of formation of any type of mountains
(c) In what four ways are mountains of great importance to man?.
(a) Three types of mountains with an example of each
- Fold mountains – the Atlas, Alps or Himalayas.
- Block (fault) mountains / horst – the Ruwenzori (or the Vosges).
- Volcanic mountains – Mount Cameroon (or Kilimanjaro).
(Residual mountains, such as inselbergs on the Jos Plateau, are also acceptable.)
(b) Process of formation of fold mountains
Fold mountains are formed by compression (lateral squeezing) of the earth's crust. Over long periods, thick layers of sediment collect in a large downwarp of the crust called a geosyncline, usually beneath a sea. When two crustal plates move towards each other, the intervening sediments are squeezed from both sides. Because they cannot escape, the rocks are buckled and folded into a series of upfolds (anticlines) and downfolds (synclines). Continued pressure raises these folds high above sea level to form fold mountains; where pressure is very great the folds may become overfolded or overthrust. The Himalayas, formed by the collision of the Indian and Asian plates, are a good example.
(c) Four ways mountains are of great importance to man
- They act as sources of rivers (water towers), feeding streams used for water supply, irrigation and hydro-electric power.
- They influence climate and rainfall, causing relief rainfall on their windward slopes and creating cooler, healthier highland areas.
- They are storehouses of minerals, forests and good grazing/farming land on their slopes and provide sites for tourism and mountaineering.
- They serve as natural boundaries and defensive barriers between peoples and countries.