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Plate Tectonics

Plate Tectonics. Earth’s Layers Continental Drift Seafloor Spreading Plate Tectonics Theory. Earth’s History. How old is our Universe?. 13.7 billion years old. How old is Earth?. 4.6 billion years old. Earth was once made of molten lava and magma, eventually cooling to igneous rock.

reese-roberson
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Plate Tectonics

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  1. Plate Tectonics Earth’s Layers Continental Drift Seafloor Spreading Plate Tectonics Theory

  2. Earth’s History

  3. How old is our Universe? 13.7 billion years old

  4. How old is Earth? 4.6 billion years old

  5. Earth was once made of molten lava and magma, eventually cooling to igneous rock

  6. Weathering, Erosion, Compaction, Cementation, Heat, and Pressure eventually formed the rocks that cover our Earth’s surface.

  7. What we know about Earth’s history comes from studying its rocks and rock formation and even the rocks from outer space

  8. Meteorites • All meteorites formed about the same time that Earth formed, so studying them helps us study Earth. • Meteorites have not been affected by erosion, weathering or other forces the way Earth’s rocks have.

  9. Studying Earth’s Rocks

  10. Rock Layers • Which book was placed here first? • The bottom one! • Sedimentary rocks often follow a similar pattern, oldest rocks are found on the bottom. http://www.prehistoricplanet.com/news/index.php?id=48

  11. Digging through the layers of rocks, helps us understand more about the history of Earth.

  12. Fossils • Most fossils are found in Sedimentary rock layers • Why? • Heat, pressure, and melting would probably destroy fossils during the formation of Igneous and Metamorphic rocks

  13. The Grand Canyon (AZ) was carved by the Colorado river, exposing millions of years worth of rock layers.

  14. Sometimes, the rock layers aren’t always horizontal…

  15. And sometimes ocean fossils are found high in the mountains… Why?

  16. Turns out, our Earth’s surface is constantly shifting and changing. • Sometimes layers get pushed around.

  17. I wonder what’s inside Earth? • Only in the last 200 years, have we begun to understand the structure and formation of our Earth.

  18. Homework: Draw a picture of an apple/egg/avocado cut in half and explain why this is similar to the layers of Earth’s interior. Page 135

  19. Skin = crust “fruit” = mantle Seeds = inner core Seed coat = outer core

  20. shell = crust white = mantle Outer yolk = outer core Center yolk = inner core

  21. “fruit” = mantle skin = crust Seed center = inner core Seed shell = outer core

  22. Earth’s Layers

  23. Earth’s Layers

  24. Crust (10-25 miles) 1,800 miles Mantle 1,430 miles Outer Core 750 mile radius Inner Core Inside OurEarth

  25. The crust is made of soil, water and rock. The mantle is hot. Part melted and part solid iron and magnesium. The outer core is made of hot liquid nickel and iron. The inner core is made of solid nickel and iron. Composition of the Earth’s Layers

  26. The Lithosphere is made of the crust and upper mantle • The Lithosphere is broken into many sections or plates. • Some plates are lighter than others.

  27. The lithosphere is made of two igneous rock types: • Continental crust - granite (light) • Oceanic crust - basalt (heavy) • Because granite is lighter than basalt, the continents sit on top of the denser oceanic plates

  28. Mantle is the largest layer over 1800 miles thick • It is composed of mostly liquid rock that moves due to temperature differences • 1800 degrees F at the top, 4000 degrees F near the bottom.

  29. Outer Core-Very hot liquid metals 4,000 degrees F to 9000 degrees F • Made of Nickel and Iron • This liquid core produces a magnetic field that helps protect earth from coronal mass ejections (CME’s) produced by the sun.

  30. Protective Magnetic Field

  31. In the Inner Core, temperatures and pressures are so great, the liquid metals are forced back into a solid despite the high temperatures that would normally melt them. • 45,000,000 pounds of pressure per square inch. • 3,000,000 times more pressure than felt at sea level.

  32. How do we know what’s inside? • Geologists study earthquakes and volcanoes Seismic waves caused by earthquakes change direction as they move through different materials(such as solids and liquids) http://www.classzone.com/books/earth_science/terc/content/investigations/es0402/es0402page03.cfm Earthquake wave animation: http://neic.usgs.gov/neis/eq_depot/2002/eq_021103/ak_seismic_waves.html

  33. I’m going to dig a hole to _____

  34. Dig a hole to the other side of Earth http://www.ubasics.com/dighole/ http://www.livephysics.com/ptools/dig-hole-through-earth.php

  35. I’m going to dig a hole to China! • You will have to start in Chile, South America

  36. Will you make it to the other side? • If you could survive the temperatures (over 8,000 degrees F) and the pressure (3,000,000 times the force of gravity) and you could “climb” out the other side (down is towards the center of Earth), then YES! • If you could just freefall all the way through Earth (8,000 miles) it would take you about 67 hours falling at 120 mph. http://www.daviddarling.info/childrens_encyclopedia/Dig_a_Hole_to_China_Chapter5.html

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