Sir Benjamin Geography Notes

GLACIATION  Glaciation refers to the process whereby a certain area on the earth’s surface is affected by glaciers (moving ice). Glaciation also refers to the process that takes place due to the influence of moving ice. Glacial erosion Glacial erosion, which predominates in the highlands, consists of the following mechanism or processes: Sapping:  This refers to the breaking up of rocks by alternate freezing and thawing of water at the bottom of cracks between a mass of ice and the side and floor of a valley, or the side of a mountain. Plucking:  This is the tearing away of the blocks of rock which have been frozen into the sides or bottom of a glacier.  Abrasion:  This is the wearing away of rocks beneath a glacier by the scouring (scrapping) action of the rocks embedded in the glacier.  Feature produced by glacial erosion i.  Cirque (corrie) : A semi-circular, steep-sided basin cut into the side of a mountain, or at the head of a valley. It is formed by the process o

WIND ACTION AND THE FEATURES IT PRODUCES Wind refers to the air in motion from high pressure to low pressure belt. Wind action is very powerful in arid and semi–arid regions. Examples of deserts include the Sahara, in North Africa, Namib, Kalahari and Gobi deserts. Types of desert surfaces Sandy Desert (Erg) : This is undulating plain of sand whose surface is blown into sand dunes and nipples. The Sand Sea of Egypt and Libya is a good example of an erg.   Stony Desert (Reg) : This is a desert surface covered with boulders and stones produced by daily temperature changes. Most of stony deserts are formed in Algeria, Libya and Egypt.   Rocky Desert (Hamada) : This consists of extensive areas of bare rock from which all fine materials have been removed by deflation. Abrasion by the fine materials polishes and smooths the rock surfaces. One of the largest hamada is Hamada el Hamra, in the Sahara of Libya.   Badlands : This is a land broken by extensive gullies, separated by st