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The Geosphere

The Geosphere. The Geosphere. The Geosphere is all the rocks , minerals , soils and lanforms of the planet , including all the internal structure of the planet .

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The Geosphere

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  1. TheGeosphere

  2. TheGeosphere • TheGeosphereisalltherocks, minerals, soils and lanforms of theplanet, includingalltheinternalstructure of theplanet. • TheGeosphereisalwayschanging and isnot in thesameformnow as itwasmillions of yearsago, and notthesmenow as itwill be in a millionyears

  3. Scientists divide the Earth into three layers based on composition • Crust – the thinnest layer of the Earth (5-20km thick) made entirely of light elements • Mantle – makes up 64% of the earth’s mass, (2900km thick) made of rocks of medium density • Core – has a radius of 3400km and composed of the densest elements

  4. Earth`s layers • Core: iron rich, dense • Mantle: less dense, rocky • Crust: even less dense, rocky. Composed of lighter elements (Oxygen and Silicon)

  5. TheGeosphereismade of rocks • Rocks are made of minerals • Minerals are made of atoms RocksMineralsAtoms

  6. Minerals • naturallyformed, inorganiccrystallinesolids, composedof atomswithspecificchemicalcomposition • notmanufactured in laboratories • Ordered in a geometricpattern • Have a range of compositions • Itisnotmade up of organiccompounds

  7. Minerals • Mineralshavespecificpropertiesdependingonwhatatomsthey are madefrom and whatstructurethey are in • Forexamplediamond and graphite are bothmadefromcarbon, butbecause of thestructurethay are VERY different!

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

  9. IdentifyingMinerals • There are a range of teststoidentifyminerals: • Streak test • Hardness test • Lustre test • Reactionwithacid • Density • Colour

  10. Streak Test • Scratchingthe mineral withglassorwith a streakplatetoseethecolour of thepowder

  11. Hardness • Hardnessis a measure of howdifficultitistoscrath a mineral. • Measuredusingthemohsscale • Scratchingminerals off eachother, you can seewhichoneisharder. • Diamondisthehardest mineral • Calcisthesoftest

  12. Mohs Scale

  13. Lustre • Lustre is a measure of howmuchthe mineral shines (reflect light)

  14. Colour, Density and Acidtests • Whatcolouristhe mineral? • Densitymeasurestherelationbetweenthemassanthevolume of the mineral. Basically “Howmuchstuff (atoms) are in a certainspace • Acidtestsmeasurethereaction of the mineral withacids. Ifthe mineral react, itprobablycontainscalcium carbonate.

  15. Uses of Minerals • Minerals are veryimprotantfortheplanet • Weneedmineralslikecopperand iron in ourbodiestosurvive • Minerals are used to make things from mobile phones and computers to jewellery

  16. Weathering • Weatheringaffectsthestructure of rocks • Weatheringis a slowprocessthathappensover a verylong time • Maintypes of weathering: • Physicalweathering • Chemicalweathering • BiologicalWeathering

  17. PhysicalWeathering • Physicalweatheringiswhenphysicalprocesses break downrocks • Examples: • When ice freezes in the crack of a rock, itexpands and makesthe crack bigger. Ifthisrepeatsthe rock can break • Whenrocksgetveryhottheyexpand. Iftheyexpand and contractrepeatedlythey can breakdownintosmallpieces

  18. ChemicalWeathering • Chemicalweatheringiswhenwaterflowsover rock and dissolvessome of thematerials in the rock. • Thismakestheroskhave a verysmoothform. • Thisishowmineralslikecalcium and magnesiumgetintowater.

  19. BiologicalWeathering • Biologicalweatheringoccurswhen living things break downrocks. • Thiscould be fromplants, orfromthechemicalsexcretedby living organismsslowlybreakingdownthe rock.

  20. Rocks • There are threemaingroups of rock types • SedimentaryRocks • IgneousRocks • MetamorphicRocks

  21. What 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

  22. Igneous Rocks • Igneous rock begins as magma under . • Magma can form: • When rock is heated • When pressure is released • When rock changes composition • Magma is a mixture of many minerals http://www.fi.edu/fellows/payton/rocks/create/igneous.htm

  23. Igneous Rocks • Coarse-grained: cools slowly under the surface of the earth, giving mineral crystals more time to grow • Fine-grained: cools quickly on the surface, with little to no crystals

  24. Igneous Rocks Coarse-Grained Fine-Grained Granite Rhyolite Gabbro Basalt

  25. Igneous Rocks • Intrusive Igneous Rocks: magma pushes into surrounding rock below the Earth’s surface • Extrusive Rocks: forms when magma erupts onto the Earth’s 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

  26. Sedimentary Rocks • Sedimentary rock is formed by erosion • Sediments are moved from one place to another • Sediments are deposited in layers, with the older ones • on the bottom • The layers become compacted and cemented together http://www.fi.edu/fellows/payton/rocks/create/sediment.htm

  27. Sedimentary Rock • Sedimentary Rocks are formed at or near the Earth’s surface • No heat and pressure involved • Strata – layers of rock • Sedimentary rock can • often contain fossils

  28. SedimentaryRocks

  29. Metamorphic Rock • Meaning to change shape • Changes with temperature • and pressure, but remains • solid • Usually takes place deep in • the Earth http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm

  30. Metamorphic Rock • Underheat and pressurethestructure of the rock changes

  31. MetamorphicRocks

  32. The Rock Cycle

  33. Identification of Rocks • Rocks can be identifiedusingthefollowingquestions: • Doesithavelayers? • Doesitcontainlargecrystals? • Isithard? • Doesitcontainfossils? • Whatcolourisit? • Doesitreactwithacid?

  34. Soils • Mixtures of differenttypes of soilsmake up thesoil of theplanet • Maintypes of soil are: • Sandy Soils • Claysoils • LoamSoils • Humus

  35. Sandy soils • Thesecontainlargeparticles, withspacebetweentheparticleswhichallowswatertopassthrougheasily

  36. Sandy Soils

  37. ClaySoils • Claysoils are made of smallparticleswithverylittlespacebetweenthem. Thismeansitisdifficultforwatertofilterthroughthesoil

  38. Loamsoils • Loamsoils are a combination of sandysoilsand clayeysoils.

  39. Humus • Humus isthethinlayercontaininglots of organicmatter, itisusuallyfoundonthesurface of soils

  40. FossilFuels • Gas and oil are formedfrom living sea creaturesthatfalltothebottom of the sea. Over time they are buriedunderlayers of sediment and thebiochemicals in theirbodiesreacttoform gas and oil. • Coal ismadefrom living plantsthatdiedbillions of yearsago, werecovered in layers of sediment and reacted in theabsence of oxygentoformcoal

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