L4.1: Plate Tectonics

• PLATE TECTONICS

  - The plate is the earth’s crust (litho) with the upper mantle (astheno) that’s broken into smaller pieces. It is theorized that plates have been in constant motion.
• ● Plate Tectonic Theory

  ○ Lithosphere is divided into several plates that move in relation to one another above a somewhat “plastic” layer inside the earth.

  ○ There are currently 20 plates identified which are pulling away from one another, sliding past one another, or coming together from opposite directions.
• ● Plate Tectonic Theory

  ○ Driving Force: Convection in the mantle. Hot material near the Earth's core rises, and colder mantle rock sinks. Remember the convection current from the previous lesson.

  ○ Continental Drift Theory + Seafloor Spreading = Plate Tectonic Theory
• ● Continental crust is thicker but the oceanic crust is denser due to its mineral composition. Mas mabigat yung mga nasa OC.