Overview
This lecture explains how convection currents in Earth's mantle drive tectonic plate movement, leading to continental drift and geological activity.
Heat from the Earth's Core
- Earth's core generates heat through radioactive decay and leftover formation energy.
- Heat from the core rises toward the mantle.
Mantle Convection
- Rising core heat creates convection currents in the semi-solid mantle.
- Hot mantle material rises while cooler material sinks, similar to heated water circulation.
Movement of Tectonic Plates
- Mantle convection currents drag and move the tectonic plates above them.
- Plates move in three ways: away from each other (divergent), toward each other (convergent), or sliding past each other (transform).
Continental Drift
- Tectonic plate movement causes continents to slowly shift their positions.
- Continents were once joined as a supercontinent called Pangaea, but have drifted apart over millions of years.
Geological Activity
- Plate movement from convection currents leads to earthquakes, volcanic eruptions, and the formation of mountains.
- These geological events mainly occur at tectonic plate boundaries.
Key Terms & Definitions
- Convection Currents — the circular movement of material caused by heating and cooling, driving mantle and plate motion.
- Tectonic Plates — large sections of Earth's crust that move over the mantle.
- Continental Drift — the gradual movement of continents across the Earth's surface.
- Pangaea — the ancient supercontinent that existed before the continents separated.
- Divergent Boundary — where tectonic plates move apart.
- Convergent Boundary — where plates move toward each other.
- Transform Boundary — where plates slide past one another.
Action Items / Next Steps
- Review examples of geological activity at different plate boundaries.
- Study diagrams of convection currents in the mantle.