The Geosphere

The GeosphereThe GeosphereThe Geosphere is all the rocks, minerals, soils and lanforms of the planet, including all the internal structure of the planet.The Geosphere is always changing and is not in the same form now as it was millions of years ago, and not the sme now as it will be in a million yearsScientists divide the Earth into three layers based on compositionCrust the thinnest layer of the Earth (5-20km thick) made entirely of light elements

Mantle makes up 64% of the earths mass, (2900km thick) made of rocks of medium density

Core has a radius of 3400km and composed of the densest elements

Earth`s layers Core: iron rich, denseMantle: less dense, rockyCrust: even less dense, rocky. Composed of lighter elements (Oxygen and Silicon)

The Geosphere is made of rocksRocks are made of mineralsMinerals are made of atoms

Rocks Minerals AtomsMinerals naturally formed, inorganic crystalline solids, composed of atoms with specific chemical composition

not manufactured in laboratories

Ordered in a geometric pattern

Have a range of compositions

It is not made up of organic compounds

MineralsMinerals have specific properties depending on what atoms they are made from and what structure they are inFor example diamond and graphite are both made from carbon, but because of the structure thay are VERY different!

Mineral properties Are classified by the chemical composition and the crystal structure Identified by physical properties

Identifying MineralsThere are a range of tests to identify minerals:Streak testHardness testLustre testReaction with acidDensityColourStreak TestScratching the mineral with glass or with a streak plate to see the colour of the powder

HardnessHardness is a measure of how difficult it is to scrath a mineral.Measured using the mohs scaleScratching minerals off eachother, you can see which one is harder.Diamond is the hardest mineralCalc is the softest

Mohs ScaleLustreLustre is a measure of how much the mineral shines (reflect light)

Colour, Density and Acid testsWhat colour is the mineral?Density measures the relation between the mass an the volume of the mineral. Basically How much stuff (atoms) are in a certain spaceAcid tests measure the reaction of the mineral with acids. If the mineral react, it probably contains calcium carbonate.Uses of MineralsMinerals are very improtant for the planetWe need minerals like copper and iron in our bodies to survive Minerals are used to make things from mobile phones and computers to jewelleryWeatheringWeathering affects the structure of rocksWeathering is a slow process that happens over a very long timeMain types of weathering:Physical weatheringChemical weatheringBiological WeatheringPhysical Weathering Physical weathering is when physical processes break down rocksExamples:When ice freezes in the crack of a rock, it expands and makes the crack bigger. If this repeats the rock can breakWhen rocks get very hot they expand. If they expand and contract repeatedly they can breakdown into small pieces

Chemical WeatheringChemical weathering is when water flows over rock and dissolves some of the materials in the rock.This makes the rosk have a very smooth form.This is how minerals like calcium and magnesium get into water.

Biological Weathering Biological weathering occurs when living things break down rocks.This could be from plants, or from the chemicals excreted by living organisms slowly breaking down the rock.

RocksThere are three main groups of rock typesSedimentary RocksIgneous RocksMetamorphic RocksWhat are Rocks?A rock is a naturally occurring solid mixture of one or more minerals, or organic matter

Rocks are classified by how they are formed, their composition, and texture

Rocks change over time through the rock cycle

Igneous RocksIgneous rock begins as magma under .Magma can form:When rock is heatedWhen pressure is releasedWhen rock changes compositionMagma is a mixture of many minerals

http://www.fi.edu/fellows/payton/rocks/create/igneous.htmIgneous RocksCoarse-grained: cools slowly under the surface of the earth, giving mineral crystals more time to growFine-grained: cools quickly on the surface, with little to no crystals Igneous RocksCoarse-GrainedFine-Grained

GraniteGabbro Basalt Rhyolite Igneous RocksIntrusive Igneous Rocks: magma pushes into surrounding rock below the Earths surface

Extrusive Rocks: forms when magma erupts onto the Earths surface (lava), cools quickly with very small or no crystals formed

http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html&edu=high&fr=t Sedimentary Rocks

http://www.fi.edu/fellows/payton/rocks/create/sediment.htmSedimentary rock is formed by erosionSediments are moved from one place to anotherSediments are deposited in layers, with the older ones on the bottomThe layers become compacted and cemented togetherSedimentary RockSedimentary Rocks are formed at or near the Earths surface

No heat and pressure involved

Strata layers of rockSedimentary rock can often contain fossils

Sedimentary Rocks

Metamorphic Rock

http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm Meaning to change shape

Changes with temperature and pressure, but remains solid

Usually takes place deep in the EarthMetamorphic Rock

Under heat and pressure the structure of the rock changes

Metamorphic Rocks

The Rock Cycle

Identification of RocksRocks can be identified using the following questions:Does it have layers?Does it contain large crystals?Is it hard?Does it contain fossils?What colour is it?Does it react with acid?SoilsMixtures of different types of soils make up the soil of the planetMain types of soil are:Sandy SoilsClay soilsLoam SoilsHumusSandy soilsThese contain large particles, with space between the particles which allows water to pass through easily

Sandy Soils

Clay SoilsClay soils are made of small particles with very little space between them. This means it is difficult for water to filter through the soil

Loam soilsLoam soils are a combination of sandy soils and clayey soils.

HumusHumus is the thin layer containing lots of organic matter, it is usually found on the surface of soils

Fossil FuelsGas and oil are formed from living sea creatures that fall to the bottom of the sea. Over time they are buried under layers of sediment and the biochemicals in their bodies react to form gas and oil.Coal is made from living plants that died billions of years ago, were covered in layers of sediment and reacted in the absence of oxygen to form coal