Causes of ​Plate Tectonics and Plate Boundaries
Plate Tectonic Causes
Scientists believe that each continent are in different sections, and once, all of the continents in the world was one continent called the "Pangaea", and then, the tectonics started to move apart because of some movements inside the Earth, the theory, was called Tectonic theory. The scientist even believed that the seafloor and the continents move while relating to each other. They broke the Earth’s crust and part of the upper mantle into sections, which are called plates which is a layer of mantle. The two parts of the crust and the upper mantle combined is called lithosphere. The layer blow the lithosphere is the asthenosphere which is the lighter layer beneath, the two layers make up the layers of plate tectonics.
Scientists found many theories of how the layers are moving. Even though they had many different opinions of their own theories, all of them had to do with the convection current. The Earth’s core has the temperature of at least 9000 degrees Fahrenheit. Since the hot mantle has lower density, it rises up as the cold mantle sinks down taking up the space. When the hot mantle above cools, the it sinks down again and the hot mantle rises up again. This convection current doesn’t happen fast, it takes slower than a growing fingernail. The convection cells occur in the asthenosphere. Each plate has their own convection cell which moves in each different directions which pulls them apart.


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The Plates

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The Convection Current







Plate Boundaries Causes
Plate boundaries are what are found at the tip of the lithospheric plates. There are three types; convergent, divergent, and conservative(transform-fault). There are usually wide zones of deformation because of how the two plates interact. When plates move, a huge amount of energy is released between the two movements. While the plates move, they are interconnected and the plates affect each other.
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How Ocenic-continental convergence work

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How Oceanic-oceanic convergence work?

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How Continental-continental convergence works



Convergent boundaries: For convergent boundaries, when the plates move into each other, the crust just goes into the ground and recycles, this happens when the plates are moving into each other. Mountains and volcanoes occur often when this happens. There are three type of coverage for Convergent boundaries; Oceanic-Continental Convergence, Oceanic-Oceanic Convergence, and Continental-Continental Convergence.
  • Oceanic-Continental Convergence is when ocean plate pushes over to the continental plate. The continual plate is lifted up as the oceanic plate goes under the plate, the part where the plate sinks the most breaks into pieces under the crust, the pieces suddenly moves after locked into the ground, generating big earthquakes.


Oceanic-Oceanic Convergence is when the two oceanic plates pushes into each other as one sinks down beneath one, when this happens, the volcano lava gets squeezed out into the ocean creating underwater volcanoes.

  • Continental-Continental Convergence is when two continental plates goes into each other, they pushes into each other with great forces creating mountain ranges like the Himalayas.




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Creates new islands and mini underwater volcanoes

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Magma comes up when the lithosphere goes apart






Divergent boundaries: For divergent boundaries, new crust creates as the plates pull away from each other. It affects the oceans the most like when the African plate goes farther, the Atlantic Ocean grows bigger. When the plates separate, and when there is a space between the two plates, water that surrounds them take over the space.



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The plates move apart creating faults between the Earth's surface

Transform Boundaries
: When two plates past horizontally past each other. The faults are mostly found at the oceanic floor, with zigzag boundaries.



By Ivory Myat & Myrea Jagidar 7B :)

Links:
Earthquakes
Faults

Plate Tectonics
Tectonic Features
Volcanoes
Volcanoes Types


Bibliography:
http://www.platetectonics.com/book/page_5.asp
http://www.platetectonics.com/book/page_4.asp

http://www.windows.ucar.edu/tour/link=/earth/interior/plate_tectonics.html
http://scign.jpl.nasa.gov/learn/plate4.htm