When urgently sloping layer of permeable rock alteranateS with layers of

When urgently sloping layer of permeable rock

This preview shows page 104 - 107 out of 172 pages.

When urgently sloping layer of permeable rock alteranateS with layers of impermeable rock e) - Some plants have long roots to reach water table - Some have small leaves to reduce transpiration - Some have thick stem/ barks to store water - Some are leaflets to minimize water loss - Some have leathery leaves to reduce water loss 12. a ) Hamada is rocky desert while an erg is sandry desert b) - Deflation – wind remove dry and unconsolidated materials like dust and sand by lifting - Abrasion – wind use materials like sand as erosive tool, where particles are hurled n rock surface causing undercutting - Attrition – materials carried by wind rub against each other and against rocks producing rounded land grains c i) A Barchan
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- An obstacle on path of wind e.g. rock/ bush block wind causing deposition - Materials continue to built until windward side is smooth and leeward side steep forming a moon shaped feature called barchan c ii) c iii) - Pre- existing depression/ localized fault attacked by wind eddies - Depression is excavated by removal of unconsolidated materials/ wind erosion by deflation - When water bearing rock is reached/ aquifer water oozes out to collect in depression and an oasis is formed d) - Alluvial fan - Bajada - Salinas 13. a ii) - Presence of loose unconsolidated gravel/ stones/ soil particles that can easily picked by wind - Presence of little or no vegetation on the surface of desert - Presence of strong prevailing winds in deserts b) - Deflation – it is the blowing away of any dry unconsolidated materials like dust and fine particles by rolling them on the ground and lifting them up in the air - Abrasion – materials carried by wind such as sand scratch and grind rocks and ground surface - Attrition – particles carried by wind hit against each other and rocks and reduce in size in the process Wind eddie Wind Wind Before erosion Resistant Soft Erosion by abrasion greatest near ground level Eddies Water table Oasis Aquifer Water table
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c i) - Rock outcrops with alternate layers of hard and soft layers project above the surface - The softer rocks are eroded by abrasion faster than the hard rock. They are worn out more rapidly than resistant ones. This results in an irregular rock with protruding layers that alternate with hollows called pedestal c ii) - Formed where hard and soft rocks lie horizontally - Weathering attacks the soft layer leading to the formation of cracks - Wind abrasion deepens the cracks deepening them forming furrows - These furrows separate the ridges forming Zengens d) - Desert land forms e.g. Zeugeus, dunes yardang attract tourists who bring foreign exchange -Oases provide water for domestic use/ irrigation/ livestock - Oases attract settlements - Loess provide fertile land for agriculture use - Rocky and sand surfaces can hinder communication and transportation 14. a) - An ocean is a large/ extensive body of salive/ salty water occupying large basins between continents while a sea is a large body of salice/ salty water boarding a continent . b - Volcanic materials from the ocean flour add salts to the water
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