2002 WAEC Geography Theory (a) Define the term mass wasting (b) Describe two types of mass wasting (c) State...

(a) Define the term mass wasting

(b) Describe two types of mass wasting

(a) Definition - movement of weathered material (debris) under the force of gravity usually down slope

(b) Types;
- Soil creep
- Solifluction
- Landslide, Slumping, etc.

(i) Soil Creep;

It occurs in areas of deep chemical weathering on moderate slopes.
It is caused by rain drop impact and thaw and freeze of ice.
It is also caused by expansion and contraction of soil aggregates.
It is responsible for down slope tilting of trees on slopes and the movement is slow and not noticeable.

Identifying mass wasting - Description

(ii) Solifluction

It occurs in temperate and sub-polar regions *Its soil is usually saturated
Its soil and rock fragments move downslope.
Freezing and thawing alternate to supply the kinetic energy required for the debris transfer.
It is frozen creep.
Movement is not restricted to definite channels.

Identifying mass wasting - Description
(iii) Landslide:

Various forms such as shrimping, debris fall involves dry mass of earth's debris rock shrimping.
Movement of large rock debris
Over underlying weak rock
Movement is in succession
Small rock debris moving down slope at a time resulting in a number of step like terracettess, e.g. Mississippi valley.

Identifying mass wasting - Description
(c) Effects