Transcript Plate tectonics summary - Webquest Puppets bringing

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Plate tectonics
Structure of the earth
The earth is made up of different layers
Crust
Solid rocks
Mantle
Molten rock liquid
Outer core
Inner core
Molten iron
and nickel
Solid iron
This is where we live.
On the crust….
Mantle
Outer core
Inner core
Crust
Pangaea
• Pangaea was a super continent at one time.
• The map below give just one example of areas on different
continents that show the same fossils and rock types.
Pangaea
From Greek Means all land
Wegener revived the early idea of
continental drift, contending that all of the
present-day continents were connected.
He called the super continental mass Pangaea
Pangaea
Gondwanaland
Northern
Hemisphere
North America,
Europe, Asia
Laurassia
Southern
Hemisphere
South America,
India, Africa,
Antarctica and
Australia
Pangea
Pangea
The break up of Pangaea
Plate tectonics
The word, tectonic, refers to the
deformation of the crust as a
consequence of plate interaction.
This theory was developed by Alfred Wegener.
Wegener believed that all of the continents were
connected as one large land mass (he called Pangaea)
about 200 million years ago.
Plate tectonics
 The theory of plate tectonics states that the earth’s outermost layer, is
broken into 7 large rigid pieces called plates: the African, North American,
South American, Eurasian Australian, Antarctic, and pacific plates. Several
minor plates also exist. These plates fit together like a jigsaw puzzle.
• The plates consist of two types of crust: continental crust and oceanic crust.
• The theory explains the movement of the earth’s plates and the cause of
earthquakes, volcanoes, oceanic trenches, mountain ranges and many other
geologic phenomenon.
• Convection currents and gravitational forces cause the plates to move.
• There are three types of plate movements.
Evidence to support the theory
Wegener’s Evidence
Wegener’s summary was based on a number of careful observations:
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The rocks match
The physical fit between the continents
The fossil evidence
The plants and animals match
Two types of crust
The plates consist of two types of crust:
The continents are made up of continental
crust
The oceanic crust are the plates beneath
the oceans.
What cause the plates to move?
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Convection Current and gravitational
forces within the mantle cause the plate to
move.
Convection current
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Convection Current is the driving force of plate
tectonics in which hot, plastic-like material from
the mantle rises to the lithosphere, moves
horizontally, cools, and sinks back to the mantle.
The convection currents provide enough energy to
move the plates in the lithosphere.
Three type of plate movements
The plates are all moving in different directions and different speeds
(from 2cm to 10 cm per year which is about the speed at which your
fingernail grow) in relationship to each other.
The place where two plates meet is called a plate boundary.
Boundaries hav different names depending on how the two plates are
moving in relationship to each other.
The three types of plate boundaries are:
Divergent: plates move away from each other (tension) (New crust is
made.
Convergent: plates move towards each other (compression)
Mountain building (Himalayas)
Transform or lateral : plates horizontally grind against one another
(strike-slip motion) (Shallow earthquakes, Andreas Fault)