1. Section 12-2

3. Midocean Ridges Underwater mountains Ex. Mid-Atlantic Ridge Form the smallest mountain chains They have a great amount of volcanic activity

4. MIDOCEAN RIDGES

5. Ocean – Floor Spreading Occurs along midocean ridges Process that explains continental drift Lava erupts from riff valley causing ocean floor to spread New ocean floor when it hardens Rock near midocean ridge is younger

6. Ocean – Floor Spreading and Magnetic Stripes Magnetic stripes in ocean floor rocks line up with poles but the Earth’s magnetic poles reverse from time to time giving good evidence.

7. Ocean Floor Spreading does not make Earth’s Surface larger because it is being destroyed as fast as it is being made

8.  Deepest part of the ocean  V-shaped valleys along the ocean bottom near continents or island

10. SubductionOlder ocean floor moves down deep into the Earth along trenches When deep enough, the rock melts becoming part of the mantle Denser materials go down and less dense float

12. Transform Faults Thin cracks located between sections of oceanic ridges Rock on either side of the fault are moving in opposite directions Block tend to jam rather than slide smoothly past one another which causes stress to built up When rock does suddenly slip it causes earthquakes