Plate tectonics
By: Noa Bryan
Intro
• Coming from the Latin word, tectonicus,
plate tectonics essentially deals with the
large scale motions of earths
lithosphere
• The theory builds on older concepts like
continental drift for example
Earths Plates
• The Earth currently, has 7-8 major
plates that make up the surface
• These are the North American plate,
Caribbean plate, South American plate,
Antarctic plate, Pacific plate, Australian
plate, Eurasian plate and the Nazca
Plates Moving
• The plates move in relation to one
another under one of three boundaries
being:
• Convergent or collisional boundaries,
divergent boundaries, also known as
spreading centers, and conservative
boundaries
Composition
• Tectonic plates are composed of two
different types of lithosphere
• One being a thicker continental crust
• With the other being a thinner, oceanic
one
Subduction
• When discussing earths crust and its
movement, subduction is a key term
• This is the sideways/downward
movement of the edge of earths crust,
into the mantle beneath another plate
Sea-floor Spreading
• Subduction is a sort of balance with the
oceanic crust
• Oceanic crust is formed along divergent
margins due to sea floor spreading,
also refereed to as the “conveyer belt”
theory
Plate examples
• Conservative transformation of
boundaries tend to grind past each
other, and transform different faults. The
San Andreas Fault in California is a
perfect example of divergent
boundaries
Divergent
• Divergent boundaries tend to be more
constructive in nature
• This occurs when two plates slide apart
from each other, an example would be
a mid ocean ridge i.e. the Mid Atlantic
Ridge
Convergent
• Convergent boundaries tend to be more
destructive in nature, and occur when
plates slide towards each other, forming
a subduction zone, or a continental
collision
• A prime example of this would be the
Japanese island arc, or the Andes
mountain range
Plates in the Past
• Our world today would appear very
different that what it looked like billions
of years ago
• Earth was once a super continent, by
the name of Colombia, which formed
about 2 billion years ago, after breaking
up, Rodinia was formed, embodying
most of the worlds continents
Cont.
• After Rodinia broke up, the world
separated into 8 different continents
about 600 million years ago, these
continents later reassembled into
Pangaea, making all continents one
super continent, which eventually broke
up, due to plate tectonics and we have
the world we know today!
Works Cited
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"Earth Floor: Plate Tectonics." COTF. Web. 19 Apr. 2011.
<http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html>
"Plate Tectonics World Ocean Floors." Plate Tectonics. Web. 19 Apr. 2011.
<http://www.platetectonics.com/oceanfloors/index.asp>.
"This Dynamic Earth--Contents [USGS]." USGS Publications Warehouse. Web. 19 Apr. 2011.
<http://pubs.usgs.gov/gip/dynamic/dynamic.html>.
"Tectonic Plates." Moorland Boarding School and Independent School Lancashire UK. Web. 19 Apr. 2011.
<http://www.moorlandschool.co.uk/earth/tectonic.htm>
Video
• http://www.youtube.com/watch?v=GYV
S_Yh6dTk