1. Chapter 4 Quiz – Define terms
Continental drift
Pangaea
Panthalassa
Mid-Atlantic ridge
Mid-ocean ridges
Seafloor spreading
Plate tectonics
Oceanic crust
Continental crust
Lithosphere
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2. 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.
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3. 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.
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4. 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.)
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5. temperatures are hot enough to melt the rock.)
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.)
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6. Essential Question
I will be able to write a summary of plate tectonics.
Warm up
Explain how paleomagnetism proves seafloor spreading
Exit Task
What is a microplate terrane
Homework
Study for chapter 4 test
Extra credit due Friday pages 78-79
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7. 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
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8. 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.
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9. 4.1 notes objectives Explain Wegener’s hypothesis of continental drift
List evidence for Wegener’s hypothesis of continental drift
Describe seafloor spreading
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10. Explain Wegener’s hypothesis of Continental Drift
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11. 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
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12. List evidence for Wegener’s hypothesis of Continental Drift
Fit of the continents
Match of mountain belts, rock types
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13. List evidence for Wegener’s hypothesis of Continental Drift
Distribution of fossils
Paleoclimates
glaciations
tropical swamps
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14. Describe Seafloor spreading
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15. 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
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16. Describe Seafloor 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
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17. 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
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18. Describe Seafloor spreading
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19. 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
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20. Summarize the theory of Plate Tectonics
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)
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21. Summarize the theory of Plate Tectonics
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.
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22. Compare the characteristic geologic activities that occur along the three types of plate boundaries
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.
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23. Convergent Boundaries Is a collision zone between two plates.
Compare the characteristic geologic activities that occur along the three types of plate boundaries
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
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24. Transform Boundaries are Two plates are sliding past each other.
Compare the characteristic geologic activities that occur along the three types of plate boundaries
Transform Boundaries are Two plates are sliding past each other.
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25. Explain the possible role of convection currents
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
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26. Summarize the theory of Micro-plate terranes
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.
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