Inner Structure

http://www.geography.learnontheinternet.co.uk/topics/structureofearth.html

Inner Core:

•Solid

•1,500km thick

•4,3000C

•Mostly Iron

Outer Core:

•Liquid

•3,000km thick

•3,700 to 4,3000C

•Nickel-Iron alloy

•Responsible for controlling Earth’s magnetic field

Mantle:

•Mostly liquid

•3,000km thick

•1,000 to 3,700 0C

•Magnesium, Iron, Aluminum, Silicon

Crust:

•Solid

•5-40km thick

•Up to 1,0000C

•Mostly igneous rock

Asthenosphere: upper mantle

Inner Structureht

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•Lithosphere: the rigid part of the crust and upper mantle that forms the plates and is made up of rocks. The three main types of rocks are Sedimentary, Metamorphic and Igneous. Minerals are the building blocks of rocks.

•Asthenosphere: upper mantle that flows but is not a true liquid. Causes the plates to move.

•Mesosphere: makes up rest of mantle.

•Oceanic crust is very dense.

•Continental crust is less dense.

Sedimentary Rocks•Sedimentary rocks are formed when layers of sediment are deposited at the bottom of seas and lakes.

•Over millions of years, the layers underneath become squashed by the layers on top.

•The water is squeezed out of the bottom layers so that the layers become cemented together.

•Examples of sedimentary rock include:

•Sandstone – hardened sand

•Mudstone – hardened mud

•Shale – hardened mud

•Conglomerate – pebbles and other debris cemented together

•Limestone – made from lime (calcium carbonate) deposits from shells. Stalagmites and stalactites found in caves are limestone.

Sedimentary Rock & •Fossil fuels such as coal, oil and natural gas are formed in

sedimentary rock.

•Hundreds of millions of years ago the dead organisms bodies became trapped in the sedimentary layers.

•When the layers became deep enough, the intense heat and pressure caused chemical reactions in the dead organic matter and turned it into hydrocarbons.

•Humans have learnt to extract these fossil fuels from deep within the Earth and burn them in order to provide energy.

http://www.energyquest.ca.gov/story/chapter08.html

http://www.nicorinc.com/en_us/commercial/products_and_services/natural_gas_cooking.htmhttp://members.macconnect.com/users/d/

dansymonds/My%20Army%20Life.html

Metamorphic Rocks•Metamorphic rock is formed as sedimentary rock is pushed deeper into the Earth’s surface.

•Here it is heated due to the pressure from rocks layered above it and the surrounding temperatures in the mantle.

•The temperature changes the chemical composition of the rock.

•Sedimentary shale becomes metamorphic slate.

•Sedimentary limestone becomes marble which is a very hard material and has many uses in our everyday lives.

Igneous Rocks•Igneous rocks are formed when molten rock (magma if it is below the surface and lava if it is above the surface) solidifies.

•Igneous rock has crystals in it. The crystals are small if the rock has cooled quickly and large if the rock has cooled slowly.

•Examples include:

•Granite

•Pumice

•Basalt

Weathering & Erosion

Kimberley Region north Western Australia

•Weathering is the process of breaking down rocks.

•This can either be physical weathering or chemical weathering.

•Physical Weathering just breaks down the rocks into smaller pieces without altering the chemical structure.

•Chemical weathering breaks down the rocks by chemical reactions forming new compounds

•Erosion is the movement of weathered particles from one place to another.

Agents of Weathering and Erosion

Agents of Weathering

• Wind• Waves• Running Water• Extremes of heat

and cold• Acid• Tree roots

Agents of Erosion• Wind• Waves• Running Water• Glaciers

Sometimes the agents cause weatheringand erosion at the

same time

Surfers Paradise, Queensland

Wind

Bondi Cliffs Kimberley Region north Western Australia

The wind picks up sand particles acting likesand paper, weathering and eroding the rocks

Waves

The Gap, Sydney The Great Australian Bight South Australia

The energy of the waves causes parts of the cliff to be broken off and then the waves wash the

weathered material away. The cliffs are both weathered and eroded by the waves

Waves

All of these rocks were once part of the mainland and the energy of the waves has weathered and eroded

the rocks producing the 12 Apostles, caves and beaches.

The 12 Apostles Southern Coastline of Victoria

Running Water

Mungo National Park south west of NSW, near the Victorian border

The rain weathers and erodes the rocks to form the patterns shown.

Small waterfall in the Kimberly Region in north Western Australia

Running water causes both the wearing away ofrocks, making them very rounded and smooth

and the erosion of the worn away pieces

Running Water

The rain dissolves

chemicals in the rock causing

chemical weathering and erosion of the material and

producing vertical cracks.

Running Water

Chemical Weathering

Jenolan Caves NSW

Running water dissolves calcium compounds in the rocks which are then washed away leaving

large caves.

As the water evaporates from droplets stalagmites and stalactites form.

Acid & Tree Roots

Physical Weathering: The roots growing in the cracks cause the cracks to become larger until eventually pieces of rock break off.Chemical Weathering: The acid produced by the roots chemically breaks down the surrounding rock.

Different types of rocks weather and erode at

different rates

“China Wall” in the Kimberley Region.

The “wall” left standing is a quartz outcrop

Ayres Rock or Uluru, central Australia

Weathering and erosion caused this huge rock to

become exposed and stand above its surroundings.

State the agents of weathering & erosion for A & B

A. Rocks between Bondi & BronteB. Rocks along a river in the Kimberley Region in north Western Australia

State the agents of weathering & erosion for C &

D

C. Kimberly Region north West Australia

D. Kimberly Region north West Australia

State the agents of weathering & erosion for E &

F

The Bungle Bungles in the Kimberly RegionE F

Stopping Erosion

Plants in the sand or soil stop the sand or soil from being washed or blown away and therefore stop the

erosion

Deposition

http://www.kented.org.uk/ngfl/rivers/River%20Articles/braiding.htm

Small particles eroded upstream are deposited on the slow bend of the river and as small islands in the center shallows.

Percentage and Role of Gases in dry Air

Percent of gases in the air we breathe

Oxygen 21%

Nitrogen 78%

Carbon Dioxide & Argon 1%

•Oxygen is used by organisms to make energy during cellular respiration.

•Carbon dioxide is used by plants when photosynthesizing.

•Nitrogen is ‘fixed’ from the atmosphere by bacteria in the soil so that plants can use it.

Role of other atmospheric Gases – Ozone depletion

http://www.epa.gov/ozone/science/process.html

1. CFC’s released

2. CFC’s rise into ozone layer

3. UV releases Cl from CFCs

4. Cl destroys ozone

5. Depleted ozone produces more UV

6. More UV leads to more skin cancer

Role of other atmospheric Gases – Ozone depletion

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Role of other atmospheric Gases – Green House Gases

•Greenhouses gases include: Carbon Dioxide (C02), Methane (CH4), CFCs, Water Vapour (H2O), Nitrous Oxide (N2O).

•The shorter wave length visible light comes in to the atmosphere from the sun hits the Earth’s surface and is released as heat, or infrared radiation.

•The infrared radiation is mostly absorbed by the greenhouse gases in the atmosphere and so becomes ‘trapped’ around the Earth and cannot escape.

•Without the greenhouse effect the Earth’s temperature would be much cooler.

http://www.press.uillinois.edu/epub/books/brown/ch9.html

Atmosphere vs. Space

http://starryskies.com/solar_system/Earth/atmosphere.html

References•Internet Geography [not date] Retrieved form the site: http://www.geography.learnontheinternet.co.uk/topics/structureofearth.html September 2004.

•Miles, K. & Peters, C. (1997) Earth’s Atmosphere. Retrieved from the site: http://starryskies.com/solar_system/Earth/atmosphere.html September 2004

•Ritter, M. (2003) The Physical Environment. Retrieved from the site: http://www.uwsp.edu/geo/faculty/ritter/glossary/l_n/lithosphere.html September 2004.

•http://www-class.unl.edu/geol109/earthstructure.htm ddd

•Moorland School Clitheroe [no date] Earth Science - The Rock Cycle. Retrieved from the site: http://www.moorlandschool.co.uk/earth/rockcycle.htm September 2004.

•United States Environment protection Agency (2004) The Process of Ozone Depletion. Retrieved from the site: http://www.epa.gov/ozone/science/process.html October 2004.

•University of Illinois (2003) Global Warming. Retrieved from the site: http://www.press.uillinois.edu/epub/books/brown/ch9.html October 2004.