Erosion and deposition

Question 1

Erosion, definition, types, result

Answer 1

Definition:
Movement of soil, mud, rock etc
Types:
Wind, water, ice and gravity
Result:
Landforms are created by the removal of rock and soil particles.

Question 2

Deposition, definition, types, result

Answer 2

Definition:
Laying down of eroded material.
Types:
Wind, water, ice
Result:
Landforms are built up by deposited material.

Question 3

Rivers – what are they

Answer 3

features of erosion and deposition

Question 4

Source, definition

Answer 4

Where a river starts, normally high up a mountain

Question 5

Mouth, definition

Answer 5

– Where a river ends, normally when it flows into the sea

Question 6

A river moves its load by:

Answer 6

Rolling large stones along the bottom of the channel
Carrying sand, mud and silt in suspension
Carrying minerals in solution.

Question 7

The three parts of a river are:

Answer 7

Upper course
Middle course
Lower course

Question 8

Upper course, tell me abt it

Answer 8

The highest section, found in mountains and valleys.
Erosion is the main process.
River erodes a V-shaped valley.
Straight path.
Steep downhill.

Question 9

Middle course, tell me abt it

Answer 9

River becomes wider and deeper
Valley becomes wider and flatter
Less steep
River begins to meander (bend).

Question 10

Lower course, tell me abt it

Answer 10

Gentle slopes.
River flows more slowly.
Valley is wide and almost level.
flood plains.
Large meanders and oxbow lakes.
Deposition occurs

Question 11

Longitudinal profile

Answer 11

visual representation of the height and length of the river, indicates the gradient

Question 12

Cross profile

Answer 12

shows the shape of the valley at an imaginary line drawn across the river

Question 13

cross profile of upper course of a river

Answer 13

v

Question 14

cross profile of middle course of a river

Answer 14

u

Question 15

cross profile of lower course of a river

Answer 15

_

Question 16

what does vertical erosion do?
what happens when rivers turn around obstacles of rock?
what does lateral erosion do?

Answer 16

deepens the valley.
interlocking spurs are formed.
widens the valley floor.

Question 17

what is a gorge?

what is a canyon?

Answer 17

very deep, steep-sided valley formed by an energetic river in a humid environment.
very deep, steep-sided valley formed by an exotic river in an dry area.

Question 18

Waterfalls and rapids

Answer 18

A resistant layer of rock across the course of the river can lead to a sharp change in the gradient and the formation of either a waterfall or rapids.

Question 19

Fluvial landforms formed by deposition

Answer 19

The river will deposit its load as it begins to lose energy and to slow down. This can occur in the following situations:
Speed of the water decreases.
Volume of the water decreases.
Channel of the river becomes wider.
Load of the river increases.
The fertile material deposited by a river is called alluvium.

Question 20

Alluvial fans

Answer 20

Alluvial fans form at the base of mountains when a river that is carrying a lot of sediment flows onto the flatter plain.
The sediment is deposited in the shape of a fan and the river splits into distributaries to flow round the deposited material.

Question 21

Floodplain

Answer 21

the river becomes a wide, flat floodplain with a very gentle gradient. Numerous depositional landforms can be found on the floodplain

Question 22

Meanders

Answer 22

A meander is a bend in a river.
Erosion occurs on the OUTSIDE of bends.
Deposition occurs on the INSIDE of bends

Question 23

Oxbow lakes

Answer 23

As the outer banks of a meander continue to be eroded, the 2 outer bends meet and cuts through the neck of the meander.
Water takes the shortest route and doesn’t go round the bend.
More deposition is laid and the meander is cut off.

Question 24

Delta

Answer 24

The river slows down as it enters the sea and deposits its load at the mouth of the river.
The deposited sediment at the mouth of the river builds up from fertile, flat landforms called deltas. The river splits into distributaries in order to flow through the deposits and reach the sea.

Question 25

Soil

Answer 25

A thin layer on the surface of the Earth

Question 26

Natural erosion

Answer 26

– soil removed naturally by wind and water movement

Question 27

Natural erosion takes place at the same rate as?

Answer 27

soil is formed.

Question 28

Topsoil

Answer 28

Has the most nutrients, often the first to be removed by erosion.

Question 29

Humans contribute to soil erosion in which 3 ways?

Answer 29

agriculture
construction
mining

Question 30

what are six ways agriculture contributes to soil erosion

Answer 30

overgrazing
lack of crop rotation
farming on a slope
removing trees
surface irrigation
using pesticides/chemical fertilizers

Question 31

Agriculture - solutions

Answer 31

Contour ploughing and leave unploughed grass strips between ploughed lands.
Drip irrigation
Avoid overgrazing
Allow indigenous plants to grow that will bind the soil.
Limit the use of pesticides and fertilisers.
Use crop rotation system.

Question 32

Construction, how does it contribute to soil erosion?

Answer 32

Land is cleared for buildings or roads, soil is exposed and eroded.
When roads, factories, e.t.c, large areas of land are covered by tar and concrete.
These surfaces cannot absorb the rain and increases run-off.
Run-off in urban areas = contaminated with fuel, oil and other chemicals.
Construction vehicles compact soil, increases run-off.
soil and sediment carried from construction sites bury plant and animal habitats needed for healthy rivers and wetlands.

Question 33

how does Mining contribute to erosion?

Answer 33

rock and soil are disturbed by drilling or earth moving.
Water is contaminated by poisons and chemicals from the mine
Open cast mining destroys landscapes, forest and wildlife habitats at the site of the mine