Lecture Notes: Plate Tectonics

Introduction to Plate Tectonics

• Earth's surface is a thin layer of rock (lithosphere) on magma.
• Lithosphere is divided into tectonic plates.
• Tectonic activity forms mountains and other geological structures.

Objectives

• Describe geological changes/events at plate boundaries.
• Understand three plate boundary types: convergent, divergent, transform fault.
• Explain earthquakes and their relation to faults.

Earth's Layers

• Core: Dense, solid nickel and iron, releases heat.
• Mantle: Surrounds core, filled with magma.
• Asthenosphere: Semi-solid rock layer above the mantle.
• Lithosphere: Brittle rock layer, contains tectonic plates.
• Crust: Outermost layer, supports life.

Types of Plate Boundaries

Divergent Plate Boundaries

• Plates move apart due to rising magma.
• Creates mid-oceanic ridges, volcanoes, seafloor spreading, rift valleys.

Convergent Plate Boundaries

• Plates collide, one is subducted under the other.
• Forms mountains, island arcs, earthquakes, volcanoes.
• Oceanic-continental collisions create coastal mountain ranges and trenches.
• Continental-continental collisions form large mountain ranges like the Himalayas.

Transform Fault Boundaries

• Plates slide past each other, creating faults.
• Stress release causes earthquakes.

Convection Cycles

• Heating/cooling cycles of magma.
• Hotspots create divergent boundaries, mid-oceanic ridges.
• Magma can force through the lithosphere, forming volcanoes and islands.

Convergent Boundary Details

• Oceanic-Oceanic: Subduction forms volcanoes, island arcs, trenches.
• Oceanic-Continental: Subduction leads to volcanoes on land, coastal ranges like the Andes.
• Continental-Continental: Forms mid-continental mountain ranges.

Transform Faults and Earthquakes

• Plates slide, edges lock, stress builds, leading to earthquakes.
• Transform faults are key earthquake locations.

Ring of Fire

• Pattern of volcanoes around the Pacific plate due to convergent zones.
• Convergent boundaries lead to volcanic activity.

Earthquake and Volcano Prediction

• Transform faults indicate earthquake zones (e.g., California, Haiti).
• Divergent boundaries create mid-oceanic ridges and volcanoes.
• Hotspots can form island chains.

Conclusion

• FRQ Skill: Explain environmental concepts using diagrams.
• Consider how subduction leads to volcanic activity.

Practice Activity

• Use diagrams to explain tectonic processes.

Additional Resources: Check other notes and videos for further study.