Plate

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Plate Tectonics
Are you living on a moving plate?
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PLATE TECTONICS
PLATE TECTONICS
Plate Tectonics Is.

• A theory developed in the 1960s by a man named,
  Alfred Wegener.
• This theory explains the movement of our earths
  plates.
• The discovery of this idea explains the cause of
  earthquakes, volcanoes, mountain range
  formations, and oceanic trenches.

The theory of plate tectonics (meaning "plate
structure") was developed in the 1960's. This
theory explains the movement of the Earth's
plates (which has since been documented
scientifically) and also explains the cause of
earthquakes, volcanoes, oceanic trenches,
mountain range formation, and many other geologic
phenomenon. The plates are moving at a speed
that has been estimated at 1 to 10 cm per year.
Most of the Earth's seismic activity (volcanoes
and earthquakes) occurs at the plate boundaries
as they interact.                              
                 The top layer of the Earth's
surface is called the crust (it lies on top of
the plates). Oceanic crust (the thin crust under
the oceans) is thinner and denser than
continental crust. Crust is constantly being
created and destroyed oceanic crust is more
active than continental crust.
The theory of plate tectonics (meaning "plate
structure") was developed in the 1960's. This
theory explains the movement of the Earth's
plates (which has since been documented
scientifically) and also explains the cause of
earthquakes, volcanoes, oceanic trenches,
mountain range formation, and many other geologic
phenomenon. The plates are moving at a speed
that has been estimated at 1 to 10 cm per year.
Most of the Earth's seismic activity (volcanoes
and earthquakes) occurs at the plate boundaries
as they interact.                              
                 The top layer of the Earth's
surface is called the crust (it lies on top of
the plates). Oceanic crust (the thin crust under
the oceans) is thinner and denser than
continental crust. Crust is constantly being
created and destroyed oceanic crust is more
active than continental crust.
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Did You Know That

• We live on a plate that is constantly moving

• Plates are sections of the crust and the upper
  mantle. They float on the mantle

• There are 9 plates on our earth that are each
  70-150 km. thick

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There are 9 major plates on our earth African
Plate, Antarctic Plate, Arabian Plate, Eurasian
Plate, Indian Plate, Nazca Plate, North American
Plate (we live on this one), Pacific Plate, South
American Plate
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Every year plates move about 1-10 cm. across the
upper mantle. They move horizontally and
vertically. Most volcanic activity occurs when
plates bump into each other and slide under one
another.
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PLATE TECTONICS
Type of Crust Average Thickness Average Age Major Component
Continental Crust 20-80 kilometers 3 billion years Granite
Oceanic Crust 10 kilometers Generally 70 to 100 million years old Basalt
Wegner theorized that 200 million years ago our
continents were all together in one gigantic
landmass. He named this large continent, PANGAEA.

The theory of plate tectonics (meaning "plate
structure") was developed in the 1960's. This
theory explains the movement of the Earth's
plates (which has since been documented
scientifically) and also explains the cause of
earthquakes, volcanoes, oceanic trenches,
mountain range formation, and many other geologic
phenomenon. The plates are moving at a speed
that has been estimated at 1 to 10 cm per year.
Most of the Earth's seismic activity (volcanoes
and earthquakes) occurs at the plate boundaries
as they interact.                              
                 The top layer of the Earth's
surface is called the crust (it lies on top of
the plates). Oceanic crust (the thin crust under
the oceans) is thinner and denser than
continental crust. Crust is constantly being
created and destroyed oceanic crust is more
active than continental crust.
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How Do Plates Move?
Many different things happen when plates
interact. They separate from each other
(sea-floor spreading), collide into each other
(mountain formation), and slip under each other
(subduction zones),
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Divergent Plate Movement
Sea floor spreading is when 2 plates move away
from each other, which creates new ocean crust.
The crust is created from magma that comes from
the earths mantle.
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Convergent Plate Movement
When plates collide, the crust is destroyed and
that plate becomes smaller in size. When 2
oceanic plates hit each other, one might go under
the other creating magma from the mantle to rise
forming a volcano.
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