What is an ice sheet?

KCSE Geography Paper 1 2006 Section B Question 8.

(a) (i) What is an ice sheet? 

• It is a continuous mass of ice covering a large area/ surface 

​(ii) Give two reasons why there are no ice sheets in Kenya 

• Kenya experience  high temperatures  under which  ice- sheets cannot from
• Most parts of Kenya have low  altitudes
• Kenya is found  at low  latitudes

​(iii) Explain three factors that influence the movement of the ice from the place where it has accumulated 

• Gradient of the  land- Ice moves faster  when the  slope is steep
• Temperatures/ seasonal changes-Higher temperatures result into thawing, leading  to faster movement of ice
• Nature of the surface – when the surface on which  ice is moving is rough, it causes friction lowering  the speed  of the  movement of ice
• Size/ thickness  of glacier – large  masses of ice  exert pressure  which  lead to melting  of ice  underneath. This  increases  the speed of ice movement

​(b) Describe how an arête is formed 

• Two adjacent cracks/ hollows exists  on a mountain  side
• The two  hollows/ cracks are filled with  ice
• The ice erodes the sides  through plucking and deepens the hollow through abrasion
• Through erosion, the  back walls  of the  hollows slowly recede
• Eventually the hollows/ ciques are separated  by a knife- edged ridge 
• The ridges called  an arête

​(b) The diagram below shows types of moraines in a valley glacier

(i) Name the type of moraines marked S, T and V 

• S- Medial
• T- Lateral
• V- Terminal

​(ii) Explain four positive effects of glaciation in lowland areas. 

• Glacial  till provides fertile  soils for arable farming
• Ice sheets, in  their scouring effect reduce the  land  surface and  depth to expose  mineral seams  which become easy  to extract
• Outwash  plains comprises  of sands and  gravel which are used as materials for building  and  construction
• Lakes formed though  glaciation can be exploited for various economic uses such as fishing, transportation or as tourist attraction.
• Ice  melts into rivers exploited for domestic use
• Glaciated  features are tourists attractions
• Glaciated lowlands are generally flat due  to erosion  and  deposition and are ideal for construction of  buildings and communication lines

​Related Geography Searches on glaciation Form 3 Level

Read More