Download The Pacific Ring of Fire

Canadian Landforms (page 22-29)
BUILDING MOUNTAINS
A geologic ______________________ has been going on for the past ________ billion years or so.
Stresses and strains inside the Earth have been heaving up _____________________. Meanwhile, the
forces of _______________ keep wearing them down.
The Earth in Motion
If you cut out the ______________________ on a world map, you’d be surprised at how well some of
them fit together. Almost a century ago, German geographer ____________________________ noticed
this pattern. Wegener believed that the continents had once been joined in one land mass that he called
__________________, meaning “all lands.” He proposed the theory of ___________________________,
which suggests that the continents gradually moved away from one another over time.
The problem with Wegener’s _______________________________________ was that he could not
explain how massive continents could _______________ across the face of the Earth. Most scientists
__________________ continental drift theory. Years later, it turned out that Wegener was __________
– and it was a _______________________ who helped discover the reason why.
Scientists rejected the theory of continental drift when it was first put forward because ______________
could not explain the driving force behind the movement of the continents.
Plate Tectonics
Think of the Earth as a round egg. __________________ sits on the thin, brittle outer shell, called the
____________________, or crust. Beneath the lithosphere is the _________________, a zone of molten
magma where you’d find the egg white. At the center, the Earth’s ______________is like the yolk. It is
the __________________ furnace that _____________ the rocks of the mantle above it.
In the 1960s, Canadian ___________________________ got people interested in continental drift again.
He recognized that __________________ could form deep in the mantle, and that __________________
could circulate above these hot spots, just as _________________water swirls in a heated pot on a
stove. These ________________________________ might provide enough ________________ to push
the crust apart, as Wegener suggested.
Since then, _____________________ have confirmed that the ______________________ (Earth’s crust)
has many _______________ called ______________. These plates are still moving. The field of
________________________________ investigates how moving plates can create _________________,
build ________________________, and trigger _______________________.
Volcanoes
Canada has no active _____________________ today, but some along the Pacific Coast are classed as
____________________or sleeping volcanoes. This means they have been active in the recent past and
could erupt again. These ________________Coast _________________________are
part of the ______________________________________ a global system of
________________ volcanic mountains that circle the __________________ Ocean.
What causes volcanoes? Scientists believe there are “_____________________” in
the Earth’s _______________. Rising heat sets the molten material of the
_________________ into huge ______________________ motions like warm air circulating in a room.
As these _______________________________________ swirl, they drag the __________________ of
the lithosphere (crust) with them. __________________open along the plate _____________, and
_________________ forces its way through.
Fold Mountains
If you put a pile of binder paper between two
textbooks and slowly push the two textbooks
together, you will make a model of ___________
mountains. The textbooks are like thick __________
carrying ____________________, while the paper
represents soft ______________________ rock layers
on
an
ocean
plate.
Your
arms
are
like
___________________currents __________________
the
plates
together
to
build
_________________________. This is how most of
__________________ mountain _________________
were
formed.
For
example,
the
___________________ Mountains were folded by the
_____________________ of the Pacific and North
American Plates.
The diagram to the right, shows how Canada’s Rocky
Mountains formed millions of years ago. The Rockies
(located in Alberta) as well as the Coastal and Columbia Mountains (located in British Columbia) are still
growing higher today as the North American plate and the Pacific plate collide.
The Pacific Ring of Fire
Study the map above. Follow the location of the Pacific ring of Fire.
1. Which parts of Canada (provinces and/or territories) does it pass through?
2. Compare the location of volcanoes in the Ring of Fire with plate boundaries. What pattern do you
notice? What might explain this pattern?
Canadian Landforms (page 22-29)
BUILDING MOUNTAINS
A geologic tug-of-war has been going on for the past four billion years or so. Stresses and strains inside
the Earth have been heaving up mountains. Meanwhile, the forces of erosion keep wearing them down.
The Earth in Motion
If you cut out the continents on a world map, you’d be surprised at how well some of them fit together.
Almost a century ago, German geographer Alfred Wegener noticed this pattern. Wegener believed that
the continents had once been joined in one land mass that he called Pangaea, meaning “all lands.” He
proposed the theory of continental drift, which suggests that the continents gradually moved away from
one another over time.
The problem with Wegener’s Continental Drift Theory was that he could not explain how massive
continents could move across the face of the Earth. Most scientists rejected continental drift theory.
Years later, it turned out that Wegener was right – and it was a Canadian who helped discover the
reason why.
Scientists rejected the theory of continental drift when it was first put forward because Wegener could
not explain the driving force behind the movement of the continents.
Plate Tectonics
Think of the Earth as a round egg. Canada sits on the thin, brittle outer shell, called the lithosphere, or
crust. Beneath the lithosphere is the mantle, a zone of molten magma where you’d find the egg white.
At the center, the Earth’s core is like the yolk. It is the nuclear furnace that melts the rocks of the mantle
above it.
In the 1960s, Canadian J. Tuzo Wilson got people interested in continental drift again. He recognized that
hot spots could form deep in the mantle, and that currents could circulate above these hot spots, just as
boiling water swirls in a heated pot on a stove. These convection currents might provide enough force to
push the crust apart, as Wegener suggested.
Since then, geologists have confirmed that the lithosphere (Earth’s crust) has many pieces called plates.
These plates are still moving. The field of plate tectonics investigates how moving plates can create
volcanoes, build mountains, and trigger earthquakes.
Volcanoes
Canada has no active volcanoes today, but some along the Pacific Coast are classed as dormant or
sleeping volcanoes. This means they have been active in the recent past and could erupt again. These
West Coast volcanoes are part of the Pacific Ring of Fire, a global system of active volcanic mountains
that circle the Pacific Ocean.
What causes volcanoes? Scientists believe there are “hot spots” in the Earth’s core.
Rising heat sets the molten material of the mantle into huge circular motions like warm air
circulating in a room. As these convection currents swirl, they drag the plates of the
lithosphere (crust) with them. Cracks open along the plate edges, and magma forces
its way through.
Fold Mountains
If you put a pile of binder paper
between two textbooks and slowly push
the two textbooks together, you will
make a model of fold mountains. The
textbooks are like thick plates carrying
continents, while the paper represents
soft sedimentary rock layers on an
ocean plate. Your arms are like
convection currents dragging the plates
together to build mountains. This is how
most of Canada’s mountain ranges were
formed. For example, the Rocky
Mountains were folded by the collision
of the Pacific and North American
Plates.
The diagram on the right shows how
Canada’s Rocky Mountains formed
millions of years ago. The Rockies (in
Alberta) as well as the Coastal and
Columbia Mountains (in British
Columbia) are still growing higher today
as the North American plate and the
Pacific plate collide.
The Pacific Ring of Fire
Study the map above. Follow the location of the Pacific ring of Fire.
1. Which parts of Canada (provinces and/or territories) does it pass through?
The Ring of Fire passes through Canada’s West/Pacific coast – British Columbia and Yukon.
2. Compare the location of volcanoes in the Ring of Fire with plate boundaries. What pattern do you
notice? What might explain this pattern?
You notice that the Ring of Fire is found along the Pacific Plate boundary or edges of the Pacific Plate.
Volcanoes occur where:



there are cracks in the Earth’s crust
where tectonic plates subduct (one plate is drawn down beneath the crust)
where tectonic plates are pulling away from each other