Two process through which wind erodes the surface

KCSE Geography Paper 1 2003 Section B Question 9.

​a)(i)Two process through which wind erodes the surface

• Deflation
• Abrasion
• Attrition

​(ii) Three ways through which wind transports its load

Suspension

• The fine dust particles are lifted and suspended in the air 
• Eventually they are blown away by wind currents 

Saltation

• Larger fragments/sand particles are lifted from the ground by eddy action
• They are moved in a series of hop(s)/ along with wind currents

Surface Creep

• The heavy materials/small stones.  Pebbles are dragged along the ground by wind currents

​b)(i)How an oasis is forced

• A pre-existing depression formed through faulting or otherwise is exposed to wind erosion
• Wind eddies removes unconsolidated materials through deflation
• As deflation continues, the depression is deepened and enlarged
• The process of deflation is aided by weathering
• With continued deflation, the level of the water table is reached.
• After oozes out of the ground and collects into the depression to form an oasis

​(ii) How zeugens are formed

• Zeugens are formed in desert area where alternating horizontal layers of hard and soft rocks occur
• The top layer of hard rock is jointed has cracks
• Weathering opens up the joints deepening them to reach the soft layer of rocks
• Abrasion continues, furrows are formed and gradually widened.
• The hard/resistant rock forms ridges separating the furrows
• This process creates a ridge-furrow landscape.

​You are supposed to carry out a field study of a semi-arid area in Kenya.
c)(i)Two ways of preparing for the Field study

• Reading from relevant written materials
• Assembling relevant tools/ equipment / materials for the study.
• Formulating hypothesis / objectives
• Grouping / appointing group leaders
• Planning a schedule of activities
• Carrying out reconnaissance
• Studying / drawing a route map
• Identifying methods of data collection.

​(ii)Information that would be collected through observation of the arid area

• Sparse vegetation / large patches of bare soil
• Sparse settlements
• Presence of drought resistant crops
• Stunted trees / tuffs of grass
• Dust storms / sand storms
• Evidence of wind erosion.

​(iii)Measures to be recommended for controlling desertification.

• Planting of trees
• Controlling overgrazing
• Avoiding bush fires
• Controlling tree cutting
• Practicing appropriate methods of cultivation / planting cover crop / irrigation / mulching / terracing strip cropping / contour farming.

​Related Geography Searches on Action of Wind and Water in Arid Areas Form 3 Level

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