Download Inside Earth 3.3 Volcanic Landforms

Volcanic
Landforms
Inside Earth Chapter 3.3
Pages 103-107
Shield Volcano
• Shield Volcano: a wide base mountain
with very gentle slopes
– Lava pours out in thin layers and harden on top
of older layers.
– Viscosity = Low
Viscosity
Viscosity
• Viscosity is a substance’s resistance to flow
• How much a substance tries NOT to flow
• “Go with the flow” vs. “Going against the
flowing”
Cinder Cone
• Cinder Cone: steep, cone-shaped hill or
mountain
– May produce ash, cinders and bombs
– Paricutin in Mexico (424m high)
– Viscosity = High
Composite Volcano
• Composite: gently steeping, cone-shaped
volcano which alternates eruptions of lava
flows and violent eruptions (ash, cinder and
bombs)
• Viscosity = High/Low
• Examples: Mt. St Helens,
Mt. Fuji in Japan
Exit Pass
What are the 3 types of
volcanoes? Describe one of
them.
Lava Plateau
• High, level areas formed by lava
flows
• Thin lava floods out, travels far
before cooling & solidifying
• Flooding process repeats again
& again, building up high
plateaus over millions of years
– Columbia Plateau
(Washington, Oregon, &
Idaho)
Caldera
• Massive eruption empties the main vent and
magma chamber beneath the volcano
• The hollow mountain then collapses inward
due to lack of support
• A Caldera is the large hole left behind
• Fills with pieces of the volcano, ash and water
– Crater Lake in Oregon
Soils from Lava & Ash
• Ash releases potassium, phosphorus, nitrogen,
and other materials that plants need
• Soil develops and plants are able to grow
Volcanic Neck
• Forms from when magma hardens in a
volcano’s pipe
– The softer rock wears away, exposing the hard rock
(weathering and erosion)
Sill
• Magma that squeezes in between layers of
rock and solidifies (Horizontal like a window
sill)
• Which letter shows the sill?
B in the diagram
Dike
• Hans Brinker, The Silver Skates
Dike
• Magma that forces itself across rock layers and
solidifies (Vertical cuts through rock layers)
• Which letter shows the dike?
C in the diagram
Batholith
• Large rock masses that form the core of many
mountain ranges
• Formed when a large body of magma cools
inside the crust
• Which is batholith?
– D in the diagram.
Dome Mountain
• Formed by smaller
bodies of magma, when
rising magma is blocked
by horizontal layers of
rock.
– Forces rock layers to bend
upward into a dome
shape.
– Rock layers above
eventually erodes and
leave the core exposed.
Exit Pass
What are 2 types of volcanic
landforms? Describe one of
them.
What to Work On
• Answer Section 3.3 Review questions on
page 107 (#s 1-3)
• Read and Outline Chapter 3.4, Volcanoes
in the Solar System