Volcanic Landforms

1
Chapter 3-3

• Volcanic Landforms

2
Landforms from Lava and Ash

• Rock and other material formed from lava create a
  variety of landforms
• shield volcanoes
• composite volcanoes
• cinder cone volcanoes
• lava plateaus.

3
Shield Volcanoes

• Thin layers of lava pour out of the vent and
  harden on top of previous layers
• Build a wide, gentle sloping mountain.
• Created Hawaiian Islands from a hot spot

4
Cinder Cone Volcanoes

• Steep, cone-shaped hill or mountain
• Lava is thick and stiff, produces ash, cinders,
  bombs
• Materials pile up around vent in a steep,
  cone-shaped pile.
• Paricutin in Mexico

5
Composite Volcanoes

• Lava flows alternate with explosive eruptions of
  ash, cinders, and bombs
• Tall, cone-shaped mountains in which layers of
  lava alternate with layers of ash
• Mount Fuji in Japan, Mt. St. Helens in Washington

6
Lava Plateaus

• Lava forms high, level areas
• Lava flows out of several long cracks in an area
• Thin, runny lava travels far before cooling and
  solidifying
• Floods of lava
• Columbia Plateau in Washington, Oregon, Idaho

7
Caldera

• Enormous eruptions empty magma chamber and vent
  completely.
• Mountain becomes a hollow shell
• No support, so top collapses inward
• Hole left by collapse is CALDERA

8
Soils from Lava and Ash

• Hard lava will break down over time to form soil
• Richest soils in the world
• People settle close to volcanoes to take
  advantage of the fertile soil

9
Landforms from Magma

• Features formed by magma include volcanic necks,
  dikes, and sills, as well as batholiths and dome
  mountains

10
Necks, Dikes, and Sills

• Neck giant tooth stuck in the ground
• Form when magma hardens in a volcanos pipe
• Dikes formed from magma that forces itself
  across rock layers and hardens
• Sill when magma squeezes between layers of rock

11
Batholiths

• Large rock masses
• The core of many mountains
• Formed from large body of magma cools inside the
  crust

12
Dome Mountains

• Smaller bodies of magma
• When rising magma is blocked by horizontal layers
  of rock
• Magma forces the layers of rock to bend upward
  into a dome shape
• Black Hills of South Dakota