Seafloor Spreading model

1. Seafloor Spreading model • On the thin strips, color the areas marked with an N purple and the areas marked with an S orange. • On the base, color the area with the slit purple and the area directly to the right and left of the slit area orange. Alternate these colors as you go away from the center. • Cut along the dotted lines, including the slit in the center of the base. • Place the “Tape in” side of the strips through the slit so that the arrows point out.

2. Seafloor Questions • Answer the following questions while you wait for tape. • Define the following terms: (68-71) • Mid-ocean Ridge: • Topography:  • Seafloor Spreading:  • Lithosphere:  • Asthenosphere:  • Paleomagnetism:  • What do the N and S represent? Explain why the strips of paper alternate N and S.  • Give two reasons why some of the bands are narrower than others. Wider?  • Explain how Paleomagnetism provides evidence for plate tectonics.

3. Seafloor questions 1. As the magma comes up from the center, what happens to the Oceanic Lithosphere? (The plates are pushed away from the ridge.) 2. What type of formation is formed at the mid-ocean ridge? (Ridges and valleys are formed.) 3. Where is the youngest rock located on the ocean floor? (The youngest rock will be located closed to the mid-ocean ridge. The rock gets progressively older as you move farther from the ridge crest.) 4. Where does the magma come from? (Deep within the earth’s crust where temperatures are hot enough to melt the rock.) 5. What so the stripes in the magma represent? (They represent the magnetic reversals. A polarity reversal means that the magnetic North flips to where we know the South Pole is.)

4. 4. Where does the magma come from? (Deep within the earth’s crust where • temperatures are hot enough to melt the rock.) • 5. What so the stripes in the magma represent? (They represent the magnetic • reversals. A polarity reversal means that the magnetic North flips to where we • know the South Pole is.)

5. Essential Question • I will be able to write an explanation on Wegener’s hypothesis of continental drift. • Warm up • What is continental drift • Exit Task • How does seafloor spreading prove continental drift • Homework • Vocabulary page 78 due Friday October 24th

6. Chapter 4 Vocabulary – define and give one fact • Continental drift • Pangaea • Panthalassa • Mid-Atlantic ridge • Mid-ocean ridges • Seafloor spreading • Plate tectonics • Oceanic crust • Continental crust • Lithosphere • Divergent boundary • Rift valley • Asthenosphere • Convergent boundary • Subduction zone • Ocean Trench • Island arc • Transformation boundary • Convection • Convection current • Theory of Micro plate terranes • terranes

7. Chapter 4 Standards • Plate tectonics operating over geologic time has changed the patterns of land, sea, and mountains on Earth's surface. As the basis for understanding this concept: • Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence of plate tectonics. • Students know the principal structures that form at the three different kinds of plate boundaries.

8. 4.1 notes objectives • Explain Wegener’s hypothesis of continental drift • List evidence for Wegener’s hypothesis of continental drift • Describe seafloor spreading

9. Explain Wegener’s hypothesis of Continental Drift

10. Explain Wegener’s hypothesis of Continental Drift • Continental Drift – Hypothesis by Alfred Wegener in 1912 that states continents had moved • Introduced the concept of Pangaea • Pangaea - Which means all land • Panthalassa – Which means all sea • Provided the first evidence of continental drift

11. Evidence Fit of the continents Match of mountain belts, rock types List evidence for Wegener’s hypothesis of Continental Drift

12. List evidence for Wegener’s hypothesis of Continental Drift • Distribution of fossils • Paleoclimates • glaciations • tropical swamps

13. Describe Seafloor spreading • sea-floor spreading

14. Describe Seafloor spreading • The Renewal of the Ocean Floor • Harry Hess – Suggested that the valleys were a break in the crust, that allowed magma to well up and form new crust • Proof came in the mid 1960’s from another group mapping world wide magnetic fields on land and sea

15. sea-floor spreading provides the mechanism for continental drift. Mid ocean ridges are 80,000 KM long. Continental rock is 4 billion years old. Ocean Rock is 175 Million Describe Seafloor spreading

16. Describe Seafloor spreading • paleomagnetism of the Ocean floor • fossil magnetism • symmetrical pattern of magnetic polarity (stripes) • Discovered by two different groups of scientist in 1965

17. Describe Seafloor spreading

18. 4.2 notes objectives • Summarize the theory of Plate Tectonics • Compare the characteristic geologic activities that occur along the three types of plate boundaries • Explain the possible role of convection currents • Summarize the theory of Micro-plate terranes

19. The Theory of Plate Tectonics is a theory that includes both continental drift and seafloor spreading to explain continental movements. Earth’s crust made of two types; oceanic and continental Two Levels the Lithosphere (top) and the Asthenosphere (bottom) Summarize the theory of Plate Tectonics

20. Lithospheric Plate Boundaries are not easy to identify. They can be in the sea, on land or at the edges of continents. Three types of plate boundaries. Summarize the theory of Plate Tectonics

21. Divergent Boundaries Plates are moving apart. The Asthenosphere moves up to fill the gap and form new oceanic plate. Most are found in the oceans. The rift valley is the point were the plate separates. Compare the characteristic geologic activities that occur along the three types of plate boundaries

22. Convergent Boundaries Is a collision zone between two plates. 3 types of collisions One type is a subduction, in which one plate slips under another forming a deep ocean trench. Second, two continental plates collide and form tall mountain ranges. Third, two ocean plates collide and form a ocean trench and island arch along the edge Compare the characteristic geologic activities that occur along the three types of plate boundaries

23. Transform Boundaries are Two plates are sliding past each other. Compare the characteristic geologic activities that occur along the three types of plate boundaries

24. Causes of plate motion A convection current causes the plate movement. The circular movement pulls and pushes the plate to cause the movement. The heat is generated in the core and moved to the surface by convection Explain the possible role of convection currents

25. Microplate Terranes is a theory that explains how the continents formed. Seafloor spreading carries small terranes across the sea floor until it hits a subduction zone and is pulled off and pushed onto another land form. Summarize the theory of Micro-plate terranes