Geo

• Volcano


  A mountain or a hill with an opening that connects the earth's interior to its surface and from which a variety of materials from inside of the earth is ejected onto the surface
• Volcanic landforms


  • Intrusive volcanic landforms
  • Extrusive volcanic landforms
• Intrusive volcanic landforms


  Formed when magma cools inside the earth's crust
• Extrusive volcanic landforms


  Formed on the surface by the cooling of lava as well as by the accumulation of solid volcanic material
• Sill


  A mass of magma which has solidified along the bedding plane
• Laccolith


  A mass of magma which has intruded between rock layers so that when it solidifies it causes the layer of rock above it to arch upwards
• Dike


  A mass of magma which cools across the bedding plane in a vertical or lateral direction
• Batholith


  A large dome-shaped mass of magma which is formed deep inside of the earth's crust and often acts as a magma chamber
• Volcanic plug


  A volcanic feature formed when magma hardens within the vent of an active volcano
• Magma


  Molten material inside of the earth
• Lava


  Molten material on the surface
• Types of lava


  • Basic lava
  • Acidic lava
• Basic lava


  Hotter than acidic lava, has a low silica content, fluid in nature, able to flow faster and over longer distances
• Acidic lava


  Has a higher silica content, viscous in nature, flows more slowly and solidifies closer to the vent
• Basic lava


  Associated with calm or effusive eruptions
• Acidic lava


  Associated with explosive eruptions
• Solid materials ejected from a volcano

  • Ash
  • Cinder
  • Bomb
  • Block
• Ash


  The finest solid material ejected from the volcano, can be very dangerous and hazardous
• Cinders or lapilli


  Pebble-shaped volcanic materials
• Bombs


  Larger materials with aerodynamic shapes
• Blocks


  The largest solid volcanic materials, may even be materials that have broken off the cone
• Lava plateau


  Formed from basic lava, where lava is ejected from a vent or a long crack and flows over a long distance, creating a generally flat area
• Shield volcano


  Formed where basic lava is ejected from a central vent and flows over long distances to create a cone that is low and has a gentle side
• Acid lava dome


  High dome-shaped volcanic cone with a narrow base and steep convex slopes, formed by the eruption of acidic lava
• Composite cone (Strata volcano)

  Large and steep cone with alternating layers of lava and ash
• Ash and cinder cone


  Volcanic cone with concave slopes formed from the accumulation of pyroclastic materials including cinder and ash
• Caldera


  Large basin-shaped depression formed when the top of an existing cone has collapsed after the summit or the top of the volcano has been removed by an explosive eruption
• Volcanic eruptions


  May result in volcanic structures increasing in size or the top of a volcano being blown off, creating calderas
• Dormant volcano


  A volcano which has not erupted for a long time but still has the ability to erupt
• Extinct volcano


  A volcano which has erupted in the past but has completely stopped erupting
• Extinct volcanoes


  May become subjected to processes of denudation such as erosion, weathering, or mass wasting, exposing intrusive landforms
• Hot magma coming into contact with ground water can cause the ground water to be heated up and ejected as hot springs