Weathering&chp.5 From General Geography

Front 1

What is weathering?

Back 1

Weathering is the process by which rocks at or near the earth's surface are broken down by different agents.

Front 2

Name the two main types of weathering.

Back 2

Mechanical(physical)
Chemical

Front 3

Name the processes involved in chemical weathering.

Back 3

The processes involved include solution,oxidation and hydration.

Front 4

What is carbonation?

Back 4

This one of the best known natural reactions as it is the one that attacks limestone and creates a karst scenery.

Front 5

Describe the three steps of the process of carbonation.

Back 5

1)Rain dissolves carbon dioxide from the atmosphere and forms dilute carbonic acid.
2)The carbonic acid converts the limestone into calcium by carbonate.
3)Water dissolves the calcium by carbonate and the rock thus dissolves.

Front 6

What is oxidation?

Back 6

Any mineral that reacts with oxygen in the atmosphere will produce an oxide which is usually soluble.

Front 7

Name some elements mostly affected by oxidation.

Back 7

Iron(2nd most abundant mineral),manganese and sulphur.

Front 8

What is the correct word for rust in Geography?

Back 8

Iron oxide

Front 9

What is the red colour of many soils due to?

Back 9

It is due to the iron in them.

Front 10

What is hydration?

Back 10

In the same way that combining oxygen or sulphur with a mineral can produce a soluble or weaker mineral so can the addition of water which is known as hydration

Front 11

Hydration is not identified as a single process but are apart of other processes such as,...

Back 11

It os often the first step in "sofening up" a mineral for oxidation or reduction.

Front 12

What is the end product of hydration?

Back 12

Usually a clay

Front 13

What is the product of weathering and also nature's most indestructible material?

Back 13

Clays

Front 14

________ is a clay in whose formation,hydration plays apart.

Back 14

Bauxite

Front 15

Explain chemical weathering in plants and animals.

Back 15

Bacteria in the presence of water break down certain minerals in the soil,and all plants absorb minerals from the soil.Decaying vegetation produces organic acid which causes a further break-down of minerals.All these actions help to weaken and break up the rocks.

Front 16

In which regions does chemical weathering take place?

Back 16

Chemical weathering takes place in all regions where there is rain,but it is most marked in wet regions which have high temperatures.

Front 17

In which regions does physical weathering take place?

Back 17

In all regions where there are changes in temperature but it is most marked in hot deserts which have a large daily range.

Front 18

What are plants called when they decay?

Back 18

humus

Front 19

How do plants and animals break down the soil?

Back 19

Plants and animals die

Bacteria

bacteria+water

breaks down minerals in the rocks/soil

plants aborb minerals and soil becomes depleted and weak

hydration occurs when the plants aborb the minerals and they expand.

Front 20

Name two things caused by physical weathering?

Back 20

exfoliation domes and frost action.

Front 21

Where are exfoliation domes common?

Back 21

In the Kalahari,Egyptian and Sinai Deserts

Front 22

What does physical weathering on steep slopes produce?

Back 22

Screes,which collect at the bottom of the slopes.

Front 23

Exlain how we get this type of rock break-up called exfoliation.

Back 23

In arid regions rock surfaces heat up quickly when exposed to the sun and the surface layers expand and break away.At night when the temperature falls rapidly the same layers contract and more cracks develop.In time the layers of rock peel and fall to the ground.

Front 24

Exfoliation is best seen in rocks of _______ _________.

Back 24

uniform structure

Front 25

Explain what happens in frost action.

Back 25

Water collects in the cracks of rocks .When the temperatuer falls to zero degrees the water freezes and water turns to ice which occupies a larger volume ,applying tremendous power to the sides of the cracks and the cracks widen and deepen.

Front 26

What does frost action do to rocks over time?

Back 26

Frost action over time breaks up rocky outcrops into angular blocks which later break up into small fragments.

Front 27

Frost action is very common in the _______ season in ________ regions and in some high mountains all year round eg.the Himalayas.It usually involves......

Back 27

winter,temperate.The freezing of water in the cracks of rocks during the night and the thawing of the ice during the following day.

Front 28

How do plants and animals break up rocks in physical weathering?

Back 28

The roots of plants, especially trees,can force joints and cracks apart in rocks.Some animals by borrowing also help to break up rocks, eg.beaver.

Front 29

What often protects rocks from weathering and how does this help?

Back 29

A covering of vegetation,it binds the soil together and reduces changes in temperature

Front 30

The removal of a covering if vegetation can result in.......

Back 30

soil erosion.

Front 31

What is denudation?

Back 31

The wearing down of land surface.

Front 32

Denudation can be done by:

Back 32

1.Weathering
2.Mass Wasting
3.Erosion

Front 33

What is weathering?

Back 33

the gradual disintegration of rocks which lie exposed to the weather

Front 34

What is mass wasting?

Back 34

The downslope movement of weathered material under the influence of gravity ,some types of these are landslides,mudflow,soil creep

Front 35

What is erosion?

Back 35

The removal of topsoil by by water,wind and ice.

Front 36

Name two evidence of oxidation.

Back 36

rusting of roofs and chairs.

Front 37

Carbonation forms features such as..

Back 37

swallow holes,sink holes,gryke,caves,caverns and clints