Overview
This lecture explains how convection currents in Earth's mantle drive the movement of tectonic plates, leading to continental drift and various geological activities.
Earth's Core and Heat Generation
- The Earth's core generates heat through radioactive decay and leftover heat from the planet's formation.
- This heat rises upward toward the mantle, the layer above the core.
Mantle Convection
- Rising heat in the mantle creates convection currents in the semi-solid rock.
- Hot mantle material rises toward the crust, while cooler material sinks back down, forming a continuous cycle.
Movement of Tectonic Plates
- Convection currents in the mantle drag tectonic plates on Earth's surface, causing them to move.
- Tectonic plates may move apart (divergent), move together (convergent), or slide past each other (transform boundaries).
Continental Drift
- The slow movement of tectonic plates causes continents to shift positions over millions of years.
- Continents were once joined in a supercontinent called Pangaea and now are in their current locations due to continental drift.
Geological Activity
- Plate movement leads to earthquakes, volcanic eruptions, and mountain formation.
- Geological activities mainly occur at tectonic plate boundaries.
Key Terms & Definitions
- Convection Current — The circular movement of material caused by differences in temperature and density, especially in the Earth's mantle.
- Tectonic Plate — A large, rigid slab of Earth's lithosphere that moves over the mantle.
- Continental Drift — The gradual movement of continents across Earth's surface due to tectonic plate movement.
- Pangaea — An ancient supercontinent that included all present-day continents joined together.
Action Items / Next Steps
- Review how mantle convection causes tectonic plate movement.
- Prepare for questions on the processes leading to earthquakes, volcanoes, and mountain formation.