1. CONTINENTAL DRIFT AND PLATE TECTONICS

2. PANGEA

5. Evidence of continental drift
1. Continents fit together like jigsaw puzzle
2. Same type of fossils on different continents
3. Rock types, ages and structures that match up
Glacier striations in South America and Africa
5. Shell fossils at top of Himalayas Mountains (30,000 feet)

6. NEW EVIDENCE Ocean floor mapping
* Found youngest rocks at mid-ocean ridges and rocks get older on both sides as you move away from the ridge

8. 2. Magnetic Striping
Stripes of alternating magnetic polarity on each side of mid-ocean ridge

10. 3. Seafloor Spreading Crust is “recycled”
New crust created at mid-ocean ridges
Oldest rock destroyed in deep ocean trenches

11. 4. Earthquakes and Volcanoes
Located at plate boundaries (along ridges and trenches)
Ring of Fire - boundary around Pacific Ocean where many tectonic plates meet and move against each other

12. Earth’s Crust OCEANIC CONTINENTAL
Denser, Basaltic, THINNER Mafic – rich in Iron (Fe) and Magnesium (Mg)
CONTINENTAL
Lighter, Granitic, THICKER Felsic – rich in Aluminum (Al) and Silicon (Si)
ESRT page 10

13. The Crust
The crust is composed of two rocks. The continental crust is mostly granite. The oceanic crust is basalt. Basalt is much denser than the granite. Because of this the less dense continents ride on the denser oceanic plates.