(a) Describe plucking as a process in glacial erosion. (b) Explain three conditions that lead to glacial deposition. (c) The diagram below shows features resulting from glacial deposition on a lowland area. (i) Name the features marked X, Y and Z

Describe plucking as a process in glacial erosion.

11/2/2021

KCSE Geography Paper 1 2010 Section B Question 8.

pressure from the overlying mass office cause freeze — thaw action.
melting water fills the cracks/joints in the bed rock.
as water freezes it exerts pressure on the cracks enlarging them.
the enlarged cracks lead to disintegration of the rock.
the rock debris are scoured/pulled off the mother rock by the moving ice.
The disintegrated rock eventually gets embedded within the mass of ice.
As the ice moves; it pills out/gorges out the embedded rock from the mother rock.

rising temperatures lead to melting of ice thereby causing the ice to deposit its load.
change of gradient to relatively flat surface will reduce the velocity of the glacial movement which will subsequently lead to deposition of fluvial-glacial materials.
alternating warm and cold periods lead to seasonal melting of ice which allows materials embedded in the ice to be released and deposited.
stagnation/accumulation of glacier leads to pressure at the base of the glacier which in turn leads to melting of ice at the base.
friction at the base and sides of a glacier and a rough surface leads to melting of ice, causing the ice to deposit its load.

Moving ice carries solid materials
Moving ice stagnates
Ice at the snout melts
Melting ice releases its load
Gradually the load piles into a ridge
Over time the ridge forms a horse-shoe shape/block of solid materials called terminal moraine.

Glacial till provides fertile soils which are suitable for arable farming.
Ice sheets in their scouring effect reduce the surface which may expose the minerals making them easy to extract.
Out wash plains comprise of sand and gravel which are used as building materials.
Glacial lakes found in lowland areas can be exploited for various economic uses such as fishing/transportation.
Glaciation forms features such as drumlins/eskers which are tourist attractions.
Glaciated lowlands are generally flat and ideal for establishment of settlements/development of transportation network.