Volcanoes

• What is a hotspot?


  A small area of the earth’s crust that is part of the mantle, produces magma and makes chains of volcanoes over millions of years
• 2 types of volcanoes?

  • Shield
  • Composite
• 4 Plate boundaries?

  1. Destructive
  2. Constructive
  3. Conservative
  4. Collision
• What happens at a constructive plate boundary?

  • Plates pull apart
  • Mantle rises
  • Volcano is formed
• What happens at a destructive plate boundary?

  • Oceanic plate is forced under the continental
  • Mantle rises Volcano
  • Volcano(and earthquake) formed
• 2 types of tectonic plates

  Oceanic

  Continental
• What tectonic plate is heavier?

  Oceanic
• Describe the characteristics of a shield volcano

  • Wide, sloping volcanoes
  • Erupt more frequently but less aggressively
  • Balsatic lava, non acidic, low viscosity
• Describe the characteristics of a composite volcano

  • Steep sides
  • Longer periods between eruptions but more aggressive
  • Andesite lava, high viscosity
• Define convection currents

  • Heat can be transferred from one place to another by convection currents
  • In fluids, hotter, less dense material rises, colder,denser material sinks