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37 Cards in this Set

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What is weathering?
Weathering is the process by which rocks at or near the earth's surface are broken down by different agents.
Name the two main types of weathering.
Mechanical(physical)
Chemical
Name the processes involved in chemical weathering.
The processes involved include solution,oxidation and hydration.
What is carbonation?
This one of the best known natural reactions as it is the one that attacks limestone and creates a karst scenery.
Describe the three steps of the process of carbonation.
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.
What is oxidation?
Any mineral that reacts with oxygen in the atmosphere will produce an oxide which is usually soluble.
Name some elements mostly affected by oxidation.
Iron(2nd most abundant mineral),manganese and sulphur.
What is the correct word for rust in Geography?
Iron oxide
What is the red colour of many soils due to?
It is due to the iron in them.
What is hydration?
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
Hydration is not identified as a single process but are apart of other processes such as,...
It os often the first step in "sofening up" a mineral for oxidation or reduction.
What is the end product of hydration?
Usually a clay
What is the product of weathering and also nature's most indestructible material?
Clays
________ is a clay in whose formation,hydration plays apart.
Bauxite
Explain chemical weathering in plants and animals.
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.
In which regions does chemical weathering take place?
Chemical weathering takes place in all regions where there is rain,but it is most marked in wet regions which have high temperatures.
In which regions does physical weathering take place?
In all regions where there are changes in temperature but it is most marked in hot deserts which have a large daily range.
What are plants called when they decay?
humus
How do plants and animals break down the soil?
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.
Name two things caused by physical weathering?
exfoliation domes and frost action.
Where are exfoliation domes common?
In the Kalahari,Egyptian and Sinai Deserts
What does physical weathering on steep slopes produce?
Screes,which collect at the bottom of the slopes.
Exlain how we get this type of rock break-up called exfoliation.
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.
Exfoliation is best seen in rocks of _______ _________.
uniform structure
Explain what happens in frost action.
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.
What does frost action do to rocks over time?
Frost action over time breaks up rocky outcrops into angular blocks which later break up into small fragments.
Frost action is very common in the _______ season in ________ regions and in some high mountains all year round eg.the Himalayas.It usually involves......
winter,temperate.The freezing of water in the cracks of rocks during the night and the thawing of the ice during the following day.
How do plants and animals break up rocks in physical weathering?
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.
What often protects rocks from weathering and how does this help?
A covering of vegetation,it binds the soil together and reduces changes in temperature
The removal of a covering if vegetation can result in.......
soil erosion.
What is denudation?
The wearing down of land surface.
Denudation can be done by:
1.Weathering
2.Mass Wasting
3.Erosion
What is weathering?
the gradual disintegration of rocks which lie exposed to the weather
What is mass wasting?
The downslope movement of weathered material under the influence of gravity ,some types of these are landslides,mudflow,soil creep
What is erosion?
The removal of topsoil by by water,wind and ice.
Name two evidence of oxidation.
rusting of roofs and chairs.
Carbonation forms features such as..
swallow holes,sink holes,gryke,caves,caverns and clints