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  • 1.Geological EvolutionGeological Evolution

2. What are Rocks?What are Rocks? A rock is a naturally occurringA rock is a naturally occurring solid mixture of one or moresolid mixture of one or more minerals, or organic matterminerals, or organic matter Rocks are classified by how theyRocks are classified by how they are formed, their composition,are formed, their composition, and textureand texture Rocks change over time throughRocks change over time through the rock cyclethe rock cycle 3. AnimationAnimation http://www.bbc.co.uk/schools/ks3 bitesize/science/environment_eart h_universe/rock_cycle/activity.sht ml 4. Types of RocksTypes of Rocks Sedimentary Rocks Metamorphic RocksIgneous Rocks 5. Igneous RocksIgneous Rocks Igneous rock begins as magma.Igneous rock begins as magma. Igneous rocks form from theIgneous rocks form from the cooling of magma or lava.cooling of magma or lava. The nameThe name igneousigneous comes from the Latincomes from the Latin wordword ignisignis, which means fire., which means fire. http://www.fi.edu/fellows/payton/rocks/create/igneous.htm 6. Sedimentary RocksSedimentary Rocks http://www.fi.edu/fellows/payton/rocks/create/sediment.htm 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 7. Sedimentary RockSedimentary Rock 8. Metamorphic RockMetamorphic 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 Earth 9. THE ROCK CYCLE SEDIMENTARY METAMORPHIC Heat & Pressure IGNEOUS Heat & Pressure Weathering, Erosion, Deposition, Cementation, Compaction Weathering, Erosion, Deposition, Cementation, Compaction Melting & Cooling Melting & Cooling Weathering, Erosion, Deposition, Cementation, Compaction Heat & Pressure Melting & Cooling 10. Where do IGNEOUS ROCKS form? 11. Extrusive igneous rocks form on or near the surface. Intrusive igneous rocks form below the surface. 12. Where do sedimentary rocks form? 13. SEDIMENTARY ROCKS form near the surface under water by COMPACTION from a few layers above. 14. Where do METAMORPHIC ROCKS form? 15. METAMORPHIC ROCKS form deep underground by Pressure from many layers above. 16. THE ROCK CYCLE 17. http://www.bbc.co.uk/schools/ks3bitesize/shttp://www.bbc.co.uk/schools/ks3bitesize/s cience/environment_earth_universe/rock_cience/environment_earth_universe/rock_ cycle/activity.shtml ****cycle/activity.shtml **** http://www.makemegenius.com/video_plahttp://www.makemegenius.com/video_pla y.php?id=108y.php?id=108 18. FossilsFossils Fossils are usuallyFossils are usually found infound in sedimentarysedimentary rocks.rocks. When an organismWhen an organism dies, its soft partsdies, its soft parts often decay quicklyoften decay quickly leaving only theleaving only the hard parts tohard parts to fossilize.fossilize. Ex. Bones, Shells,Ex. Bones, Shells, Teeth, or SeedsTeeth, or Seeds 19. FossilsFossils FossilsFossils areare preserved remains orpreserved remains or traces of living things.traces of living things. Most fossils formMost fossils form when living things diewhen living things die and are buried byand are buried by sediments.sediments. The sediments slowlyThe sediments slowly harden into rock andharden into rock and preserve the shape ofpreserve the shape of the organisms.the organisms. Scientists who studyScientists who study fossils arefossils are paleontologists.paleontologists. 20. Types of FossilsTypes of Fossils Petrified FossilsPetrified Fossils:: fossils in whichfossils in which minerals replace all orminerals replace all or part of the organism.part of the organism. Ex: petrified woodEx: petrified wood When the object isWhen the object is buried by sediment,buried by sediment, water rich in mineralswater rich in minerals seeps into the cells.seeps into the cells. After the waterAfter the water evaporates, hardenedevaporates, hardened minerals are leftminerals are left behind.behind. 21. Types of FossilsTypes of Fossils Molds andMolds and CastsCasts AA moldmold is ais a hollow area inhollow area in sediment in thesediment in the shape of anshape of an organism or partorganism or part of an organism.of an organism. AA castcast is a copyis a copy of the shape ofof the shape of an organism.an organism. 22. Types of FossilsTypes of Fossils Trace FossilsTrace Fossils provide evidence ofprovide evidence of the activities ofthe activities of ancient organisms.ancient organisms. Ex: footprints, animalEx: footprints, animal trails, or animaltrails, or animal burrows.burrows. 23. Types of FossilsTypes of Fossils Carbon FilmsCarbon Films:: anan extremely thin coatingextremely thin coating of carbon on rock thatof carbon on rock that forms when materialsforms when materials that make up anthat make up an organism becomeorganism become gases and escapegases and escape leaving only carbonleaving only carbon behind.behind. 24. Types ofTypes of FossilsFossils PreservedPreserved RemainsRemains areare formed when anformed when an organism isorganism is preserved with littlepreserved with little or no change.or no change. For example whenFor example when organisms becomeorganisms become preserved in tar,preserved in tar, amber (tree sap),amber (tree sap), and freezing.and freezing. 25. Why Study Fossils?Why Study Fossils? Scientists studyScientists study fossils to learn whatfossils to learn what past life forms werepast life forms were like.like. PaleontologistsPaleontologists classify organisms inclassify organisms in the order in whichthe order in which they lived.they lived. All the informationAll the information scientists havescientists have gathered is called thegathered is called the fossil recordfossil record.. 26. Fossil RecordFossil Record The fossil recordThe fossil record provides evidenceprovides evidence about the history ofabout the history of life on Earth.life on Earth. The fossil recordThe fossil record also shows howalso shows how different groups ofdifferent groups of organisms haveorganisms have changed over time.changed over time. It also providesIt also provides evidence to supportevidence to support thethe theory oftheory of evolution.evolution. 27. Remember!Remember! A scientific theory isA scientific theory is a well-tested concepta well-tested concept that explains a widethat explains a wide range ofrange of observations.observations. The fossil recordThe fossil record shows that millionsshows that millions of types ofof types of organisms haveorganisms have evolved.evolved. However, manyHowever, many others becameothers became extinct.extinct. 28. Finding the Age of Rocks ThroughFinding the Age of Rocks Through Rock DatingRock Dating 29. R O C K D A T I N G 30. Ages of RocksAges of Rocks TheThe relative agerelative age ofof a rock is its agea rock is its age compared to othercompared to other rocks.rocks. Use words like:Use words like: older or youngerolder or younger TheThe absolute ageabsolute age of a rock is theof a rock is the number of yearsnumber of years since the rock wassince the rock was formed.formed. Ex: 358-360 myaEx: 358-360 mya 31. Rock Joke!!Rock Joke!! What does a rock wantWhat does a rock want to be when it growsto be when it grows up?up? A Rock Star!!A Rock Star!! 32. The Position ofThe Position of Rock LayersRock Layers It can be difficult toIt can be difficult to determine a rocksdetermine a rocks absolute age. Soabsolute age. So scientists use thescientists use the lawlaw of superpositionof superposition.. According to theAccording to the lawlaw of superpositionof superposition, in, in horizontalhorizontal sedimentary rocksedimentary rock layers the oldest layerlayers the oldest layer is at the bottom. Eachis at the bottom. Each higher layer ishigher layer is younger than theyounger than the layers below it.layers below it. 33. Law of SuperpositionLaw of Superposition TheThe Law of SuperpositionLaw of Superposition states thatstates that inin undisturbedundisturbed rock layers the oldestrock layers the oldest layer is on the bottom and thelayer is on the bottom and the youngest rock layer is on the top.youngest rock layer is on the top. 34. The Grand CanyonThe Grand Canyon Youngest Oldes t 35. UnconformitiesUnconformities AnAn unconformityunconformity is ais a gap in the geologicgap in the geologic record that mostrecord that most commonly occurs whencommonly occurs when rock is erodedrock is eroded exposing older rockexposing older rock and then new rockand then new rock forms on the muchforms on the much older rock.older rock. The layering of newThe layering of new rock on the much olderrock on the much older rock leaves a gap inrock leaves a gap in the geologic record.the geologic record. 36. Other types of UnconformitiesOther types of Unconformities Faulting- Movement of the Earths plates causes rock to crack and shift. Intrusion- Magma from the Earths mantle moves into the rock layers, cools and hardens. (Igneous Rock) 37. Other types of Unconformites (cont.)Other types of Unconformites (cont.) Folding- Earths plates are pressing together. This movement causes them to bend and fold. This process forms mountains. Erosion- described earlier. Layers of rock are washed away and new rock built on top. Leaves gaps in geologic record. 38. Examples of when the Law ofExamples of when the Law of Superposition may notSuperposition may not applyapply FoldingFaulting Intrusion Erosion 39. Use the link below to watchUse the link below to watch a simulation ofa simulation of unconformities.unconformities. www.classzone.comwww.classzone.com 40. Rock Joke!!Rock Joke!! How do rocks washHow do rocks wash their clothes?their clothes? The Rock Cycle!!The Rock Cycle!! 41. Other Clues toOther Clues to Relative AgeRelative Age Clues FromClues From Igneous RockIgneous Roc