GEOGRAPHY AND HISTORY

  Processes of Glacial Erosion 1. Plucking: This is a process of glacial erosion where the glacier freezes in the joints and beds of the underlying rocks, tears out individual blocks and drags them away. Glacial landforms include; landforms of Highland glaciation Landforms of Glaciated Lowlands. 2. Abrasion: In this process of glacial erosion, the glacier scratches, scrapes, polishes and scours the floor and sides of the valley with the debris embedded in it. The Importance of Glaciation to Man The old glacial lake beds with their alluvium support agricultural activities   Large lakes formed by former glaciation, e.g. the Great Lakes of North America, are used for navigation Large lakes formed by glaciation also cut deep overflow channels while draining off, making natural route ways across a mountainous terrain, e.g the Hudson-Mohawk Gap that links the interior with the Atlantic Seaboard of U.S.A. In the out-wash plains, eskers and kames have been excavated by...

  CIRQUES/CORRIE/TARNS/CWMS . These are semi-circular steep sided rock basins which have been cut into the sides of a glaciated mountain.  It is formed when water enters the rocks and freezes breaking them down. The joints become enlarged. Abrasion drags the debris over the rock floor deepening the depression, back wall cutting or recession also enlarged the depression as well as steepening the sides. Plucking also steepens the cirque, when filled with water, it forms a tarn (lake) such as teleki and mawenzi on mountain Kenya and Kilimanjaro respectively. Others are Lac du Noah, Lac du Catherin and Lac du vent on mountain Rwenzori. Pyramidal peak /horn this is a jagged peak formed by the steepening of the back walls of several cirques which lie on the sides of a glaciated mountain. Two or more cirques cut back into the original mountain sides leaving an isolated peak called a pyramidal peak.  These peaks become shaped by frost action. Examples include kibo, mawenzi on mou...