Transcript 6.1_Notes_powerpoint

• I will be able to:
• Demonstrate my knowledge
of Energy Transfer and Plate
Tectonics.
Volcanoes &
Plate Tectonics
CH 6 Prentice Hall
p.178-181
Objective: I will be able to describe what a
volcano is and identify the parts of a volcano.
• What is A Volcano?
– A weak spot in the
crust where molten
material, or magma
comes to the
surface.
• Volcanic Activity is a
constructive force
that adds new rock
to existing land or
forms new islands.
Objective: I will be able to describe where
volcanoes are found on Earth.
• Location of Volcanoes
– Most occur along
diverging boundaries
such as the mid-ocean
ridge or in subduction
zones.
Objective: I will be able to describe where
volcanoes are found on Earth.
• Location of Volcanoes
– About 600 active
volcanoes on land,
more lie beneath the
sea.
– Occur in belts that
extend across
continents and oceans.
– Ring of Fire-formed by the
many volcanoes that rim
the Pacific Ocean
I will be able to describe why volcanoes form
where they are found on Earth.
• Divergent Boundaries
– Form along the midocean ridge.
• Ridge a long
underwater rift valley.
• Lava pours out of the
cracks in the ocean
floor.
• Iceland- is a volcano on
the mid-ocean ridge
that has reached the
surface.
I will be able to describe why volcanoes form
where they are found on Earth.
• Convergent Boundaries
– Plates collide
• Denser plate
subducts towards the
mantle.
– Forms a deep-ocean
trench
– The crust melts and
forms magma that
rises.
– Rising magma erupts
through a volcano on
the surface.
I will be able to describe why volcanoes form
where they are found on Earth.
• Convergent Boundaries
– Ocean/Ocean
• Denser ocean plate
subducts
– Forms a deep sea
trench
– Forms an island arc of
volcanoes.
» Japan
» New Zealand
» Aleutians
I will be able to describe why volcanoes form
where they are found on Earth.
• Convergent Boundaries
– Continent to Ocean
• Dense ocean plate
subducts
• Forms a deep sea
trench
• Forms volcanoes on the
land.
– Mt. St Helens
– Andes Mountains- S.
America.
I will be able to describe why volcanoes form
where they are found on Earth.
• Hot Spot Volcanoes
– An area where magma from deep
within the mantle melts through
the crust like a blow torch.
– Lie in the middle of plates.
• Hawaii- formed in the middle of the
Pacific Ocean plate.
• Yellowstone- formed under the
continent.
– The plate travels over the hot spot.
• Created a chain of islands to form
Hawaii
I will be able to describe why volcanoes form
where they are found on Earth.