• Created by: Om4r
  • Created on: 17-04-19 16:44
What is Weathering?
The breakdown or disintegration of rock in situ at or close to the ground surface by the action of weather, plants or chemicals
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What are the 3 types of Weathering?
Mechanical, Biological and Chemical
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What is Mechanical Weathering?
The breakup of rocks without any chemical changes taking place
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What are the 3 types of Mechanical Weathering?
Freeze-thaw, Salt crystallisation and wetting+ drying
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How does Freeze-thaw occur?
when water enters a crack or joint in the rock when it rains and freezes in cold weather, frozen water expands by about 10% breaking (widening) the crack
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What is Salt- Crystallisation?
When Salt water evaporates it leaves salt crystals behind , these grow overtime and exert pressure on rock causing it to break up
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How does Wetting and drying cause weathering?
Frequent cycles of wetting and drying (common on the coast). Rocks rich in clay such as shale expand when wet and contract when dry causing them to crack and breakup
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What is Biological Weathering?
The breakdown of rock by organic activity
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How do Thin Plant roots cause weathering?
They grow into small cracks in a cliff face, cracks widen as roots grow breaking up the rock
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How does Water running through decaying vegetation cause weathering?
It becomes acidic, leading to increased chemical weathering
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How do Birds and animals cause Weathering?
They dig burrows into cliffs
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How do marine organisms cause Weathering?
They can burrow into rocks and secrete acid
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What is chemical weathering?
Involves a chemical reaction where salts may be dissolved or clay like deposit may result which is easily eroded
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What are 3 ways Chemical Weathering occur?
Carbonation, Oxidation and Solution
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What is Carbonation?
When rainwater absorbs Carbon dioxide from the air forming a weak carbonic acid, this reacts with calcium carbonate in rocks forming calcium bicarbonate which is easily dissolved
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What rocks have Calcium Carbonate?
Limestone and Chalk
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When is Carbonation most effective? Why?
In winter because colder rainwater absorbs more carbon dioxide
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What is Oxidation?
The reaction of rocks minerals with oxygen e.g. iron forming a rusty red powder leaving rocks more vulnerable to weathering
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What is Solution?
The dissolving of rock minerals
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What is Scree?
A build up of debris at the base of a cliff
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Other cards in this set

Card 2


What are the 3 types of Weathering?


Mechanical, Biological and Chemical

Card 3


What is Mechanical Weathering?


Preview of the front of card 3

Card 4


What are the 3 types of Mechanical Weathering?


Preview of the front of card 4

Card 5


How does Freeze-thaw occur?


Preview of the front of card 5
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