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Volcanoes

IV. Volcanic Landforms

A. Landforms from lava and ash (see Figs. 2 and 3 below)

  

  1. Volcanic mountains (Activity: topographic profiles of volcanoes)
    a. Shield Volcanoes (resemble warrior's shield)

    1. Large
    2. Gentle slopes
    3. Built primarily of flows of fluid basaltic flows
    4. Examples: Hawaii, Iceland, Olympus Mons (Mars)

b. Composite volcanoes (also called stratovolcanoes)

  1. Steep sides
  2. Alternating lava flows and layers of pyroclastic material
  3. Andesite-rhyolite (may also erupt basalt)
  4. Examples: Cascade volcanoes, Andes, Mt. Pinatubo

c. Cinder cones

  1. Relatively small
  2. Form by accumulation of pyroclastic fragments (cinders)
  3. Slopes controlled by angle of repose (30-40 degrees)
  4. Example: Particutín, Mexico
  1. Lava plateaus

    Built up of multiple lava flows
    Example: flood basalts of Pacific Northwest

  2. Caldera (Spanish for "kettle") - large depression formed by collapse of emptied magma chamber.

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updated January 28, 2002

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