(a)(i)Differentiate between Erosion and Mass movement (ii) Name two features each of river erosion and mass movement. (b) Describe the factors that affect mass movement.
Explanation
(i) Differences between Erosion and Mass Movement — Erosion is the gradual removal of top soil while mass movement is the movement of loose rock materials down slope — Agents of erosion are running water, winds, waves and glacier while that of mass movement entails the force of gravity. —Erosion involves scratching, polishing and plucking of loose, rock surfaces while mass movement involves creeping, flowing, slumping, sliding and falling. (ii) Main features of River Erosion Gorges — Cayons — waterfalls — Rapids — Capture — Potholes — Interlocking spurs. Main Features of Mass Movements — Slumps and sl;de scars Slumped block — Hummocky topography — Talus — Screes (b) Factors Affecting Mass Movement — Gradient of the slope determines rate of movement, e.g steep slope encourages faster mass movement — the try activities of man on slope could promote or reduce movement of loose rock materials. — Presence of vegetation tends to reduce the rate of movement down the slope and vice versa. — Depth of weathering — mass movement can be more active in areas of deep weathering. — Presence of lubricating moisture e.g presence of rain water, ice, etc tends to promote mass movement down slope. — The nature / weight of rock materials e.g loose and light rock materials tend to move faster than lightly held and heavy materials. — The occurrence of earthquake often triggers off mass movement of steep slopes. — Volcanic eruption can also lead to mass movement.
