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Lecture 2: Plate Tectonics
I. Structure of Earth:
- Elements: Oxygen, Silicon, Aluminum, Iron.
- Crust => Two types:
1. Oceanic Crust (OC)
=> Elements: Fe, Mg => "Mafic".
=> Heavier; Higher Density.
2. Continental Crust (CC)
=> Elements: Si, O.
=> Lighter elements; Lower Density.
- Mantle => Elements: 0, Mg, Si, Fe; located between the Core
and the Crust.
- Core => Elements: Fe, Ni.
- Crust = Lithosphere (crust and upper mantle).
=> Solid layer.
- Asthenosphere = (2nd layer) upper mantle; Plastic (halfway
between solid and liquid layer).
- Mesosphere = mantle, solid layer.
- Core = has two layers
=> Inner Core and Outer Core.
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=> Has an ability of magnetic field - protective
- Lithosphere divided into plates.
- Most plates have both continental and oceanic crust.
=> Ex: Africa, Eurasia, Antartica.
- Plates in motion can trigger earthquakes and they are very
III. Plate Tectonics
A. Divergent Plate Boundary:
- "Fiston Theory"
- Also called as constructive boundary (new young rocks are
being formed; making new rocks).
- Have classic characteristics.
- Ex: The Great Reef in Africa (Rift Valley).
- Chemistry of rock is simila