2.7

• Tectonic Plates


  Broken pieces; like pieces of a jigsaw puzzle found in the Earth's Lithosphere
• Tectonic Plate activity


  • Plays a vital role in the GEOLOGIC changes in the EARTH that occurs in the LITHOSPHERE
• How plates move


  1. Mantle convection drives plate tectonics

  2. Hot material rises over mid-ocean ridges

  3. Sinks into deep trenches

  4. Keeps the plates moving along the Earth's surface
• Plate Boundary/Margin


  The edge where two plates meet
• Types of Plate Boundaries


  • Divergent Plate Boundary
  • Convergent Plate Boundary
  • Transform Plate Boundary
• Divergent Plate Boundary


  • Boundaries where the earth's tectonic plates are moving apart
  • Magma from the mantle rises up to make new crust
  • Earthquakes occur when plates move over the mantle
• Landforms at a divergent plate boundary


  • Mid-Ocean Ridges
  • Rift Valleys
  • Shield Volcanoes
• Convergent Plate Boundary


  • Plates move towards one another
  • Can cause earthquakes and volcanoes
  • Heavier oceanic crust sinks below the lighter continental crust forming oceanic trench
  • Plate sinks into the mantle and melts to form magma
  • Magma escapes through weaknesses in the rock and rises up through a composite volcano, also known as a Stratovolcano
  • Fold Mountains formed when two continental plates collide, neither can sink and so the land buckles upwards
• Transform Plate Boundary


  Plates slide past each other in opposite directions, or in the same direction but at different speeds
• Transform Plate Boundary examples


  • San Andreas Fault
  • Alpine Fault of New Zealand
• Fold


  Formed by the bending or buckling of rock layers, as a result of great force and pressure over extremely long periods of geologic time
• Syncline


  • Rock layers bend downward in the folding process to form a trough-like physical feature
  • Often shows itself in the form of valleys and lakes
• Anticline


  • Rock layers buckle upward during folding to form an arch-like structure
  • Often shows itself in the form of mountains or ridges
• FOLDS - a wave-like geologic structure that forms when rocks deform
• FAULTS - fracture or zone of fractures between two blocks of rock
• MID-OCEAN RIDGES - an underwater mountain range, formed by plate tectonics
• RIFT VALLEYS - lowland region that forms where Earth's tectonic plates move apart
• VOLCANOES - an opening in Earth's crust that allows molten rock from beneath the crust to reach the surface
• TRENCHES - are long, narrow depressions on the seafloor
• SAN ANDREAS FAULT - the sliding boundary between the Pacific Plate and the North American Plate
• EARTHQUAKE - shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves
• PLATE BOUNDARY - the location where two plates meet
• MAGMA - molten rock