faults and folds

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Faults and Folds. Bends and Breaks. First, rocks are laid down and organized in units. Sedimentary rocks are laid down in layers like a cake by wind and water. This process is called DEPOSTION Igneous rocks are spread over large areas like maple syrup by VOLCANIC ACTIVITY. - PowerPoint PPT Presentation

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Faults and FoldsBends and BreaksFirst, rocks are laid down and organized in units.Sedimentary rocks are laid down in layers like a cake by wind and water. This process is called DEPOSTIONIgneous rocks are spread over large areas like maple syrup by VOLCANIC ACTIVITY.Metamorphic rocks gradually change from one place to the next by extreme geologic eventsRock units and large areas that consist of one kind of rock created by geologic events that happened millions of years ago.You can walk for miles and miles and just see one kind of rock.Faults and Folds are what BEND and BREAK up rock units.Fault

Fold

5FRACTURE and FLOWFractureFracture happens when rocks are at the EARTHS SURFACE and they are COOL.Fracture is what happens when rocks BREAK!Fracture = FaultsFlowFlow happens when rocks are deep UNDERGROUND and they are very HOT.Fracture is what happens when rocks BEND!Flow = FoldsForces in the EarthFaults and folds happen when masses of rock are colliding, being pulled apart, or sliding next to each other.Faults and folds happen when there are COMPRESION, TENSION or SHEAR forces.

COMPRESSION happens when two plates collide (Are pressed together)

TENSION happens when two plates SEPARATE (are pulled apart)

SHEAR happens when two plates slide past each otherLets see this in actionhttp://scign.jpl.nasa.gov/learn/plate5.htm FAULTSFaults are the result of FRACTURE. They are the result of forces in the earth that BREAK rocks. Fracture happens when rocks are cool.There are 3 major types of faults:Normal = CompressionReverse = TensionSlip-strike = Sheer

Normal FaultNormal faults occur when two plates PULL AWAY from one each other.They are caused by TENSION forces

Reverse FaultReverse faults occur when two plates are PUSHED togetherReverse Faults are caused by TENSION forces

Strike-Slip FaultsStrike-Slip faults occur when two plates slide past each otherStrike-Slip faults are caused by SHEAR forces

Lets see it in action:http://www.iris.washington.edu/gifs/animations/faults.htm

FoldsFolds are the result of FLOW. They are caused by the same forces as faults, except they happen deep UNDERGROUND where it is very hot. Because it is hot, the rock bends instead of breaking.There are two parts to a fold:The ANTICLINE is the top of the fold (think: ANTHILL)The SYNCLINE is the bottom of the fold (think: SIN)ANTICLINES and synclinesAnticlines are at the top (they are the Anthills)Synclines are at the bottom (sin = hell = bott0m)

Now, go back through your sketches and label your faults and foldsReady to test your knowledge?

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