Overview
This lecture covers the processes and landforms resulting from the convergence of tectonic plates, including explanations, demonstrations, and examples of the landforms produced.
Plate Tectonics and Plate Boundaries
- The Earth's lithosphere is divided into tectonic plates that move due to mantle convection.
- Plate boundaries are classified as convergent, divergent, or transform based on relative motion.
- Convergent plate boundaries occur when two plates move toward each other.
Convergent Boundaries: Types and Results
- Oceanic-continental convergence forms trenches, volcanic arcs, and mountain ranges.
- Oceanic-oceanic convergence creates deep-sea trenches and island arcs.
- Continental-continental convergence produces mountain ranges like the Himalayas.
Landforms Produced by Plate Convergence
- Trenches are long, narrow depressions at subduction zones.
- Volcanic arcs are chains of volcanoes formed above subducting plates.
- Fold mountains are created by the collision and compression of continental plates.
Experiments and Demonstrations
- Clay or modeling dough can be used to simulate plate movements and landform creation.
- Pushing materials together demonstrates the folding and uplift forming mountains.
- A model showing one material going under another illustrates subduction and trench formation.
Summary of Plate Convergence Effects
- Convergent boundaries recycle crust and are sites of frequent earthquakes and volcanic activity.
- The type of converging plates determines the resulting landform and geological activity.
- Most major mountain belts and deep ocean trenches are at convergent margins.
Key Terms & Definitions
- Convergent Boundary — where two tectonic plates move toward each other and interact.
- Subduction — the process where one plate sinks beneath another at a convergent boundary.
- Trench — a deep oceanic feature formed by subduction at a convergent margin.
- Volcanic Arc — a curved line of volcanoes above a subducting plate.
- Fold Mountain — a mountain formed when two continental plates collide and crumple.
Action Items / Next Steps
- Review and draw diagrams of different convergent boundaries and related landforms.
- Prepare for a quiz on the landforms produced by plate convergence.
- Observe models or create a small demonstration simulating plate convergence using soft materials.