Forces within Earth’s Crust By: Brianna Shields February 2, 2005

DO NOW 1. Which chemical is responsible for creating ozone depletion? 2. Which mineral property is the most reliable for identifying a mineral? 3. Which process carries broken down rock to new locations?

GOAL To explain the theory of plate tectonics and to relate it to areas of volcanic and earthquake activity To be aware of the constructive and destructive forces constantly acting upon the earth’s crust

Theory of Plate Tectonics Theory of plate tectonics 1. Earth is made of shifting plates beneath oceans and continents Pulling apart Moving sideways Smashing together

Earth’s Lithospheric Plates

Theory of Plate Tectonics Theory of plate tectonics 2. Earth once had one supercontinent= Pangaea EVIDENCE? Fossils Rock deposits Jigsaw puzzle continents

Continental Drift

Theory of Plate Tectonics Theory of plate tectonics 3. Earthquakes & volcanoes occur at the plate boundaries Most active plate= pacific plate = “RING OF FIRE””

Ring of Fire

9 Lithospheric Plates Eurasian Indo-Australian Antarctic Pacific North American Caribbean South American African Nazca

9 Lithospheric Plates

Plate Movement Why are the earth’s plates moving ? Convection Currents- cycling of magma in the mantle beneath the plates Hot rises, cold sinks

Tectonic Plate Boundaries 1. Convection currents Magma cycles

Tectonic Plate Boundaries 2. Ocean floor Crust, plates

Tectonic Plate Boundaries 3. MantleLayer beneath crust, with convection currents

Tectonic Plate Boundaries 4. Midocean ridge Lip of hardened rock at plate boundaries

Tectonic Plate Boundaries 5. TrenchArea where one plate is subducted beneath another

Tectonic Plate Boundaries 6. Subductio n Where ocean floor is plunging down into mantle beneath one of the plates

Tectonic Plate Boundaries 7. Ocean floor spreading Where new ocean floor is being made as magma rises up and hardens

Tectonic Plate Boundaries 8. Divergent boundaries Plates pulling apart (aka= seafloor spreading)

Tectonic Plate Boundaries 9. Convergen t boundaries Plates are meeting (one is subducting) Creates mountains

Tectonic Plate Boundaries 10. Strike slip/ transform boundaries Plates are sliding horizontally past eachother Creates earthquakes

Movements within the Earth Forces within earth’s crust 1. Fracture- crack in a rock

Movements within the Earth Forces within earth’s crust 2. Fault- crack in crust along which rocks move

Movements within the Earth Forces within earth’s crust C. Fault Mountains - middle rock between 2 faults, rises

Movements within the Earth Forces within earth’s crust D. Fault Valleys -middle rock between 2 faults drops

Movements within the Earth Forces within earth’s crust 3. Folding- rock bends A. Anticline- upward fold (mountain)

Movements within the Earth Forces within earth’s crust 3. Folding- rock bends B. Syncline- downward fold (valley)

Movements within the Earth Forces within earth’s crust 4. Stresses A. Compression- rocks squeeze together

Movements within the Earth Forces within earth’s crust 4. Stresses B. Tension- rocks pull into thin strings

Movements within the Earth Forces within earth’s crust 4. Stresses C. Shearing- rocks slide past eachother horizontally Causes earthquakes

Movements within the Earth Forces within earth’s crust 5. Other landforms A. Plateaus- flat, raised chunk of land with cliffs on sides

Movements within the Earth Forces within earth’s crust 5. Other landforms B. Domes- blister-like hill/bubble filled with molten rock

Assessment Compare and contrast fractures and faults

Assessment Describe the interior layers of the Earth

Assessment Compare the processes that create fault block mountains and valleys

Assessment Describe the activities that can occur along faultlines

Assessment Describe the types of folds that the earth’s crust can undergo

Assessment Relate the theory of plate tectonics to earthquake and volcano formation

Assessment Explain how earthquakes occur

Assessment Explain how volcanoes can occur

Assessment Compare compression, tension and shearing

Assessment Describe the differences between domes, plateaus and mountains