Lecture Notes: The Quiet Revolution of Plate Tectonics

Introduction

• Shift in understanding of Earth in the 1960s
• Development of the theory of plate tectonics
• Influences structure and behavior of Earth

Historical Context

• 16th-century speculation on landmass shapes
• Alfred Wegner (1912): Proposed Pangaea
  • Evidence: Fossils, rock types, mountain ranges
  • Concept of continental drift
• Skepticism from scientific community

Post-World War II Developments

• New oceanic evidence re-emerges
• Bruce Heason and Marie Tharp (1957):
  • Published the first physiographic map of the Atlantic Ocean floor
  • Mid-Atlantic Ridge: Discovery of ocean floor features
• Harry Hess (1960): Theory of seafloor spreading
  • Conveyor belt model of ocean floor creation and recycling
  • Robert Dietz (1961): Similar spreading seafloor theory

Seafloor Spreading Evidence

• Vine and Matthews (1963):
  • Earth's magnetic field reversals recorded in rocks
  • Magnetic stripes as historical records

The Concept of Subduction

• Oceanic crust subduction under continental crust
• Formation of subduction zones and ocean trenches
• Example: Pacific Ring of Fire

The Plate Tectonics Theory

• Development of the theory in the 1960s
• Tectonic plates floating on the asthenosphere
• Types of plate boundaries:
  • Divergent: Plates moving apart (e.g., East-Pacific Rise)
  • Convergent: Plates colliding (e.g., Andes and Himalayas)
  • Transform: Plates sliding past each other (e.g., San Andreas Fault)

Continuing Exploration and Future Questions

• Ongoing research with satellite technology
• Comparison with Venus
• Understanding the origin of plate tectonics
• Connections between tectonics and life evolution

Conclusion

• The revolution continues to impact our understanding and exploration of Earth sciences
• Upcoming topics in further lectures

Additional Notes

• Importance of contributions from young, innovative scientists
• The role of technology and funding in advancing geoscience research