1. Warm-up Week 13 Day 1
Describe Alfred Weneger’s “Continental Drift” hypothesis in your own words.
Give 4 pieces of evidence that support the “Continental Drift” hypothesis.
What problem did Weneger’s critics have with this hypothesis?

2. “Theory of Plate Tectonics”
9.2 & 9.3

3. Recall: Weneger’s Hypothesis…
Continental Drift.
Continents move…
…Through Ocean Floor?!
Wrong.

4. Q: HOW do we explain the movement of plates?!
Recall: LITHOSPHERE
Divided into 7 “PLATES”
Q: HOW do we explain the movement of plates?!

5. Theory of Plate Tectonics
Lithosphere:
Separate plates
Move around (~5 cm/year)
Movement creates earthquakes, volcanoes, mountains, and the CRUST itself.

6. Move? How!? “CONVECTION” Cycle. Hot ↑ Cold ↓ Makes Plates Move COLD
COOLS
HEATS
HOT

7. We Know…Plates Move! “BOUNDARIES” DIVERGENT TRANSFORM CONVERGENT
Destroys Lithosphere
DIVERGENT
Creates Lithosphere
TRANSFORM
No Destruction/Creation

8. Q: Creation or Destruction?...

9. Convergent. Subduction Zones: “Sub”-marine…below. Trench: Destructive
Oceanic crust is pushed down into the mantle
Trench:
Deep canyon!
Made as crust sinks

10. Oceanic-Continental Convergence.
Oceanic Plate sinks.
Heavier
Continental slides over.
Continental Volcanic Arc
Mountains made of volcanoes
Along Convergent Boundaries

11. Oceanic-Oceanic Convergence
Volcanoes!
Become Islands!
Volcanic Island Arc!
newly formed chain of volcanic islands

12. Continental-Continental Convergence
Subduction
Continent vs. Continent
Folding
Makes Mountains!

13. Divergent
Located at “oceanic ridges”
“Constructive”

14. Transform
No Destruction, No Creation.