Overview
This lecture explains convection currents in the Earth's mantle and how they drive tectonic plate movement, continental drift, and geological activity.
Heat from the Earth's Core
- The Earth's core produces heat through radioactive decay and leftover heat from Earth's formation.
- This heat rises upwards from the core towards the mantle.
Mantle Convection
- Rising core heat creates convection currents in the semi-solid mantle.
- Hot mantle material rises toward the crust while cooler material sinks back toward the core.
Movement of Tectonic Plates
- Mantle convection currents exert drag on tectonic plates, causing them to move.
- Plates can move apart (divergent), together (convergent), or slide past each other (transform boundaries).
Continental Drift
- Moving tectonic plates cause continents to slowly shift positions (continental drift).
- Continents have moved from a single landmass called Pangaea to their current locations, and this movement is ongoing.
Geological Activity
- Tectonic plate movement results in geological phenomena such as earthquakes, volcanic eruptions, and mountain formation.
- These events mainly occur at plate boundaries.
Key Terms & Definitions
- Convection Current — circular movement in a fluid where hot material rises and cool material sinks.
- Mantle — semi-solid layer above Earth's core where convection occurs.
- Tectonic Plate — rigid slab of Earth's crust and upper mantle that moves over the mantle.
- Continental Drift — gradual movement of continents across Earth's surface over geological time.
- Pangaea — ancient supercontinent from which current continents have drifted.
Action Items / Next Steps
- Review examples of divergent, convergent, and transform plate boundaries for better understanding.