Drawing things together
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Drawing things together. About how the scenery is changed. So far …. We looked at They different types of rock and how they are formed Then there was that small diversion by way of plate tectonics and volcanoes So we are now going back to scenery but from a different angle.

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Drawing things together

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Drawing things together

Drawing things together

About how the scenery is changed


So far

So far …

  • We looked at

    • They different types of rock and how they are formed

  • Then there was that small diversion by way of plate tectonics and volcanoes

  • So we are now going back to scenery but from a different angle


Do you remember what were the 2 types of processes that create sediment

Do you remember what were the 2 types of processes that create sediment?


Looking at weathering briefly first

Looking at weathering briefly first

  • Weathering is the break down of the rocks by various processes. There are 3 broad types of weathering

  • P..

  • B..

  • C..

  • Can you remember how each works?


What does erosion mean

What does erosion mean?

  • Do you remember what we said was also part of erosion- what tended to happen afterwards?

  • So we have 2 other processes following it

    • Transportation

    • Deposition

  • There are various ways that rock can be worn away – depends a bit what was is doing it (these are called agents of erosion)

  • What are the agents of erosion – the things that wear the rock away? (3 all together)


There are 3 processes at work

Erosion Transport Deposition

There are 3 processes at work

I am using my hammer to wear away this rock

I am carrying away the pieces

I cannot carry them any further so I drop them


Wind erosion

Wind Erosion

Typical sharp-edged wind erosion Grand Canyon


Water erosion near the source of a river

Water Erosion (Near the source of a river)

.

Notice the 'V' profile, absence of vegetation and steep slopes

How a waterfall and gorge are formed


Water erosion nearer the mouth of a river

Water Erosion (Nearer the mouth of a river)

.

See how the edge of this river has been eroded to form a river cliff


Water erosion coast

Water Erosion - Coast

.


There is also ice erosion

There is also ice erosion

That is what glaciers do- maybe another time?


Transportation

Transportation

  • Is the movement of eroded material by water, wind or ice.

  • And is a bit difficult to see!

But here is a lot of sediment

And

That is a tree trunk floating down the River Wye last October


Transportation1

Transportation

  • And here we have the wind doing some transporting

This one was taken in Iraq.

The soldier who took the picture said they have at least one of these a week


Deposition is a bit easier

Deposition is a bit easier!

  • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying

Kiama Downs Beach, just north of Sydney

Where is that?

See those rocks in the foreground?

They are being eroded away and will end up on the beach.


Deposition is a bit easier1

Deposition is a bit easier!

  • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying

Sand dunes

Location:

Sabria, Tunisia


Deposition is a bit easier2

Deposition is a bit easier!

  • Is what happens when the wind or the water or ice runs out of energy and drops whatever it is carrying

Mississippi Delta


Review

Review

  • 1. What ere the 4 processes involved in changing the scenery? And what do each do?

  • 2. What are the 3 agents of erosion?

  • 3. We saw various pictures – these examples of which processes?


How do these processes work

How do these processes work?

As applied to coasts, but they work river rivers too


There are 3 processes at work1

There are 3 processes at work

I am using my hammer to wear away this rock

I am carrying away the pieces

I cannot carry them any further so I drop them

Erosion Transport Deposition

Remember when we talked about rocks? Which rocks were made by wearing away, carrying the bits and then dropping them?


Erosion 1

Attrition is the collision of rock fragments in the water against one another.

The waves carrying rocks that knock against each other and pieces get broken off, making them smoother and rounder

Erosion 1


Erosion 2

Abrasion occurs when rocks and stones carried by the waves wear away the base of the cliffs

Erosion 2


Erosion 3

Hydraulic action.

When waves fall against the cliffs, air is forced into the cracks and is squashed.

As the wave withdraws, the air expands causing little explosions and so the cracks become enlarged

Erosion 3


Erosion 4

Corrosion is the process by which water reacts chemically with soluble minerals in the rocks and dissolves them. 

Erosion 4


Drawing things together

If you would like to watch the animation from which the diagrams for erosion, look here! (I borrowed it from the BBC!)

http://ysgol-rhyngrwyd.wikispaces.com/Unit+4+Changing+Earth


Transportation 1

A waves carry or transport eroded materials such as mud, sand, boulders and dissolved materials. Sometimes this is towards the land or sometimes is it away from the land but often it is along the coast to somewhere else

These materials are known as its load.

The load is carried along by four processes.

traction

saltation

suspension

solution

Transportation 1


Transportation 2

Transportation 2

  • Traction is where boulders or stones are rolled along the ocean-bed by the force of the water


Transportation 3

Transportation 3

  • Saltation is when small pebbles bounce along and leapfrog over each other.


Transportation 4

Transportation 4

  • Suspension very fine particles such as clay, silt and fine sand are carried along in the river.

  • They are held up by the water as they float because they are very, very small!


Transportation 5

Transportation 5

  • Transportation in solution is when dissolved materials resulting from corrosion (when the eroded material is dissolved out of the rocks) and are invisible to the naked eye.

You cannot see anything because they are too small!


Deposition

A waves drop their load when the speed or volume of the waves decrease.

The load, which it carries, is deposited.

The heavier material is deposited first and the finer material carried further.

Deposition is likely to occur when:

waves enter an area of shallow water

waves enter a sheltered area

there is little wind

Deposition


Can you sort the words we have learnt into erosion and deposition

Can you sort the words we have learnt into erosion and deposition?

Try here!!

http://classtools.net/my/dustbin35961TESTER.htm


Match the word to the definition

Attrition

Abrasion

Hydraulic action

Corrosion

Traction

Saltation

Suspension

Solution

The water dissolving away the cliffs

The force of the water wearing away the cliffs

Tiny particles of clay or sand being carried away by floating in the waves

Rocks hitting each other, breaking pieces off, making them smaller and smoother

Rocks wearing away the coast line

Larger boulders being dragged along the floor of the ocean

Dissolved chemical being taken away by the wave

Smaller pebbles leapfrogging over each other as they move

Match the word to the definition


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