PLATE TECTONICS

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PLATE TECTONICS

• Nafisa
• Skeie

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What is plate tectonics?
The build up of plates?
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Or is it the build up of food onto a plate?
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Geographically
Plate Large, rigid slab of Earths solid rock
Tectonics From the Greek root to build
Plate Tectonics The term which refers to how
the Earths surface is built of plates
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Earths Layers
http//homepage.usask.ca/src594/thestructureofear
th.jpg
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EGGS-celent!
http//earthquake.usgs.gov/learning/teachers/Earth
Egg.pdf
Crust
Mantle
Outer Core
Inner Core
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The Plates

• Plates large, rigid slab of Earths solid rock
• are broken pieces from the lithosphere layer
  which is the crust of the Earth
• ride on the hotter and weaker layer of the upper
  portion of the mantle called the asthenosphere
• due to the various pressure in the upper mantle,
  the layer is plastic which allows the plates of
  the lithosphere to move around
• -gt Theory of Plate Tectonics Movements of the
  Earths plates

http//stloe.most.go.th/html/lo_index/LOcanada1/10
2/images/L02_3.jpg
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Earths Major Plates
http//www.enchantedlearning.com/egifs/Earthsplate
s.GIF
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Plate Boundaries
Transform Fault (Sliding)

• two plates grind past each other without the
  production or destruction of lithosphere
• San Andreas Fault in California.
• -gt Pacific plate is moving toward the
  northwest grinding past the North American plate
  which is traveling in the opposite direction.
• - Earthquakes are triggered along the fault
  boundaries.

http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/4_1.jpg
http//www.biog1105-1106.org/demos/106/unit08/medi
a/san-andreas-fault.jpg \
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Plate Boundaries
Divergent (Constructive) Oceanic plate Oceanic
plate

• Plates move away from each other.
• When two plates diverge, factures occur which are
  immediately filled with molten rock that wells up
  from the asthenosphere. This hot material cools
  and creates a new seafloor.
• As a result, new oceanic crust (lithosphere) is
  continuously being created between the diverging
  plates.
• The older crust moves away from the boundary, as
  it does so, it cools and contracts hence
  increasing in density and in thickness.
• This is why the older and cooler oceanic crusts
  are deeper.

Hyrdrothermal vents
http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/1_1.jpg
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Plate Boundaries
Divergent Continental plate Continental plate

• Two continental plates moves apart from each
  other
• The East African rift valleys represent the
  initial stage in the breakup of a continent.
• -Volcanic mountains such as Kilimanjaro and Mount
  Kenya are examples of the rift valleys that were
  formed by the associated faulting taking place.

http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/1_2.jpg
http//taos-telecommunity.org/EPOW/EPOW-Archive/ar
chive_2008/EPOW-081027_files/P118053120Rift20Val
ley20escarpments20LR_big.jpg
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Plate Boundaries
Convergent (Subduction)

• Plates move towards each other, resulting in
  subduction (consumption) of oceanic lithosphere
  into the mantle.
• When two plates converge, the leading edge of one
  is bent downward, allowing it to descend beneath
  the other.
• This region is called a subduction zone.
• There are three types of convergent boundaries.

http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/3_1.jpg
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Plate Boundaries
Convergent Oceanic plate Continental plate
-When a continental plate collides with an
oceanic plate, the less dense continental plate
will continue on its course while the denser
oceanic plate will sink under the continental
plate and into the asthenosphere. -As the
descending plate increases in depth, the heat
generated causes partial melting of the mantle
creating magma which will accumulate beneath the
overlying continental crust. -This can result in
explosive volcanoes -Example is the Andes in
South America
Ushuaia Bay with the southernmost tip of Andes in
the background in Argentina
http//www.sema.go.th/files/Content/science/k4/003
5/F01/images/Th/03/3_2.jpg
http//img2.travelblog.org/Photos/841/2784/f/9037-
Ushuaia-bay-with-the-southernmost-tail-of-the-Ande
s-in-the-background-0.jpg
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Plate Boundaries
Convergent Oceanic plate Oceanic plate
-Two oceanic plate convergence, one will descend
beneath the other. -Triggers volcanic activity
just like the oceanic-continental convergence,
but the volcanoes forms on the ocean floor. -If
the activity continues the volcanoes will emerge
as islands in the ocean - Examples are the
Mariana Islands in the western Pacific Ocean and
the Tonga
Metis Volcano is one of the Tonga Islands
http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/3_3.jpg
http//www.cartage.org.lb/en/themes/sciences/earth
science/geology/volcanoes/currentvolcanoes/metis2.
gif
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Plate Boundaries
Convergent Continental plate continental plate
-When two plates carrying continental crust
converge it causes collision. -Since both plates
are of low density and buoyant by the nature of
the continental rock, neither will subduct.
-Folding and deforming of sediments along the
continental margins are then formed. -Example is
the Himalayas which are a result of the
Australian-Indian plate ramming into the Eurasian
plate.
http//help.berberber.com/members/sajalarora/album
s/natural-beauty-india/2026-himalayas.jpg
http//stloe.most.go.th/html/lo_index/LOcanada4/40
3/images/3_4.jpg
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Activity time!
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Snack tectonics
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Now you can EAT your snacks!Questions?
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Resources

• http//stloe.most.go.th/html/lo_index/LOcanada4/40
  3/html/1_en.htm
• http//en.wikipedia.org/wiki/Tectonic_plateDiverg
  ent_.28constructive.29_boundaries