L6 | WILSON CYCLE

• WILSON CYCLE

  • Plate tectonics is cyclic. 
  • In 1966, J. Tuzo Wilson proposed a cycle that includes continental break-up, drifting, collision and reassembly of the continent. 
• PHASES

  1. EMBRYONIC STAGE
  2. JUVENILE STAGE
  3. MATURE STAGE
  4. DECLINING STAGE
  5. TERMINAL STAGE
  6. SUTURING STAGE
• EMBRYONIC STAGE

  • formation of rift valleys due to splitting of continents
• JUVENILE STAGE

  • creation of oceanic crust below sea level as continental plates divide
• MATURE STAGE

  • broadening of the ocean basin with the development of trenches and the beginning of subduction
• DECLINING STAGE

  • continuous subduction removes the ocean's bottom and ridge leading to the formation of island arcs and trenches
• TERMINAL STAGE

  • uplift and convergence narrow the ocean basin forming young mountains
• SUTURING STAGE

  • continental collision creates high mountain ridges, transforming young mountains into mature ones
• WILSON CYCLE

  A) EMBRYONIC

  
• WILSON CYCLE

  A) JUVENILE

  
• WILSON CYCLE

  A) MATURE

  
• WILSON CYCLE

  A) DECLINING

  
• WILSON CYCLE

  A) TERMINAL

  
• WILSON CYCLE

  A) SUTURING

  
• MAIN PHASES

  • Rifting within the supercontinent leads to the opening of new ocean basins and formation of oceanic crust.
  • Passive margin cools and sinks, and sediment accumulates along the edge.
  • Convergence begins, initiating subduction and eventual ocean closure.
  • Continent-continent collision forms the next supercontinent.
• CONVECTION

  • circulation or material caused by the differences in density. 
  • occurs between the core and mantle or even between the asthenosphere and lithosphere.
• SLAB PULL

  • denser plate sinks, gravity pulls on the rest of the plate with a force. 
  • Features: subduction and trench. 
  • Subduction is a location where one plate is being pulled down into the mantle, melted, and recycled.
• RIDGE PUSH

  • result of gravitational forces acting on the young, raised oceanic lithosphere around mid-ocean ridges