After studying the continental drift theory you have an idea of what Earth looked like200- 300 million years ago. Hypothesize about what Earth will look like 100 million years from now. Draw a picture in your spiral of your hypothesis.

Continental Drift- Animated Video https://www.youtube.com/watch?v=uGcDed4xVD4

Sea Floor Ages Activity What do you think the layout of seafloor ages is? Where do you think the youngest and oldest seafloor is located? Why?

Seafloor Drilling

Resolution

Seafloor Ages Activity Choose seven different colors. Follow the instructions on the Activity sheet to color the Seafloor Ages Worksheet and answer the questions.

Today’s Schedule Finish coloring seafloor map (when finished work on geology puzzle packet) Discuss/label seafloor map Answer seafloor questions on worksheet

Seafloor Ages Map Look at your map. Figure out what you are looking at. Use a world map and label the oceans (Pacific, Atlantic) Label each body of land (gray areas) with continent names Look at the colors on the maps. What patterns do you notice?

Sea Floor Spreading Model Use the instructions to create a model. Follow the directions EXACTLY. (pg 40 has pics) Answer the lab questions on your worksheet (use Figures 19, 21 and 23 in your book) When you are finished you may continue working on your Geology Puzzle Packet

Seafloor Spreading Diagram

Read Pages 33-39 Pay Special Attention to: Diagrams Bolded words Bolded statements Section headings Check your understanding: can you answer the checkpoint and review questions?

Bill Nye Seafloor Spreading Video https://www.youtube.com/watch?v=GyMLlLxbfa4 Subduction zone- pacific rim Video: https://www.youtube.com/watch?v=NbDqJy28hBw

Seafloor Spreading Animations http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_seafloorspreading.html http://dli.taftcollege.edu/streams/geography/animations/seafloorspreading.html http://www.bioygeo.info/Animaciones/SeafloorMagnet.swf http://emvc.geol.ucsb.edu/forteachers/flashmovies/Spreading.swf

Magnetic Field Changes evidence in Seafloor

Seafloor Spreading Model- 1 What feature of the ocean floor does the center slit stand for? The center slit stands for the central valley of the mid-ocean ridge. What prominent feature of the ocean floor is missing from the model at this point? The feature that is missing the mountainous ridge.

Seafloor Spreading Model-2 What do the side slits stand for? The side slits stand for deep-ocean trenches. What does the space under the pattern stand for? The space under the paper stands for the part of the mantle called the asthenosphere.

Seafloor Spreading Model-3 How does the ocean floor as shown by the part of a strip close to the center slit differ from the ocean floor as shown by the part near a side slit? The ocean floor near the center slit is younger, hotter and less dense than the ocean floor farther away. As the floor moves away from the ridge, it cools and becomes denser. The ocean floor near the side slits is older, cooler and denser.

How does this difference affect the depth of the ocean How does this difference affect the depth of the ocean? The increased density causes the depth of the ocean to increase.

Seafloor Spreading Model-4 What do the stripes on the strips stand for? The stripes stand for the magnetic stripes in the rock of the ocean floor. Why is it important that your model have an identical pattern of stripes on both sides of the center slit? The pattern of magnetic stripes is the same on both sides of the mid-ocean ridge.

Seafloor Spreading Model-5 Explain how differences in density and temperature provide some of the force needed to cause sea-floor spreading and subduction. Temperature differences in the mantle cause convection currents. These currents cause molten rock to erupt through the valley that runs along the center of the mid-ocean ridge. As more material erupts, the sea floor spreads, cools, and becomes denser. The denser material sinks back into the mantle when it reaches a trench.

Seafloor Spreading Model-6 Use your own words to describe the process of ocean-floor spreading. Answer should include: eruption of molten material at the mid-ocean ridge the spreading of the sea floor the subduction of oceanic crust at deep ocean trenches.

What parts of the process were not shown by your model. Parts of the process not shown by the model include changes in density and the melting of the curst as it sinks back into the mantle.