Plate Tectonics

Plate Tectonics

1. Section 2: Convection and the Mantle

   • Convection Currents in Earth
     • Heat from the core & the mantle itself causes convection currents in the mantle.
   • Convection Currents
     • Heating and cooling of the fluid, changes in the fluid's density, and the force of gravity combine to set convection currents in motion.
     • The flow that transfers heat within a fluid.
   • Types of Heat Transfers
     • Radiation
     • Conduction
     • Convection

2. Section 1: Earth's Interior

   • Exploring inside Earth
     • Evidence from rock samples
       • Scientists drill holes for samples
     • Evidence from seismic waves
       • Seismic waves in Earth
   • Journey to the Center of Earth
     • Temperature
       • The deeper you go, the higher.
     • Pressure
       • The deeper you go, the stronger the pressure.
   • The Mantle
     • Lower Mantle
       • Solid and extends down the core.
     • Lithosphere
       • Uppermost part of mantle.
     • Athenosphere
       • Soft layer of mantle, bendable.
   • The Crust
     • The layer of solid rock that forms Earth's outer skin.
     • It is between 5 to 40 km thick
       • Note: Under mountains, could be 70 km!
   • The Core
     • Both together are 3486 kilometers thick.
     • Outer Core
       • A layer of molten metal that surrounds the inner core and it is 2266 kilometers thick.
     • Inner Core
       • A dense ball of solid metal that is 1216 kilometers thick.

3. Section 3: Drifting Continents

   • Continental Drift
     • Evidence from fossils
       • A fossil is any trace of an ancient organism.
     • Evidence from land features
       • Mountains & other features on the continents provided evidence for continental.
     • Evidence from Ancient Climate Zone
       • Evidence from fossils/rocks can help find out what climate it was from.
   • Wegener's Hypothesis
     • Wegener's Hypothesis was that all the continents were once joined together in a single land mass and have since drifted apart.

4. Section 4: Sea-Floor Spreading

   • Evidence for Sea-Floor Spreading
     • Ages of rocks
     • Eruptions of molten material
     • Magnetic stripes
   • What is sea-floor spreading?
     • Continually adds new material to the ocean floor.
   • Subduction at Trenches
     • Tens of million years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.
     • The process which the ocean floor sinks beneath a deep-ocean trench and back into the mantle is called SUBDUCTION.

5. Section 5: The theory of Plate Tectonics

   • How Plates Move
     • The theory of plate tectonics explains the formation, movements, and subduction of Earth's plates.
   • Plate Boundaries
     • There are three kinds of plate boundaries: spreading boundaries, colliding boundaries, and sliding boundaries. A different type of plate movement occurs along each type of boundary.
     • Spreading Boundaries
       • The place where two plates move apart is called a spreading boundary.
     • Colliding Boundaries
       • The place where two plates come together, or collide, is called a colliding boundary.
     • Sliding Boundaries
       • A sliding boundary is a place where two plates slip past each other, moving in opposite directions.