(a) What is a plateau? (b) Describe the mode of formation of: (i) Tectonic plateau (ii) Dissected plateau. (c) Outline three ways in which plateau are impor...

(a) What is a plateau?

A plateau is an extensive area of elevated, fairly level or gently undulating highland that stands above the surrounding land and usually has at least one steep side. It is also called a tableland.

(b) Mode of formation:

(i) Tectonic plateau: Formed by earth movements (crustal forces). A large block of the earth's crust is uplifted more or less evenly by vertical forces, or is left standing between two faults (a raised block), so that a broad surface is raised to a high level without much folding. Some are formed by outpourings of lava (basalt) that build up flat-topped lava plateaux.

(ii) Dissected plateau: Formed when an existing plateau is deeply eroded by rivers and other agents. Streams cut deep valleys and gorges into the raised surface, breaking it into a rugged mass of ridges, hills and valleys. What remains of the original level surface is seen only in the accordant hill tops.

(c) Three ways plateaux are important to man:

• Mining: many plateaux are rich in minerals (e.g. tin and coal on the Jos Plateau), supporting the mining industry.
• Hydro-electric power: rivers descending the plateau edge provide waterfalls and rapids used to generate HEP.
• Settlement, farming and grazing: the cooler, healthier climate of high plateaux favours settlement, arable farming and livestock rearing, and can attract tourism.