Plate Tectonics - DanielleWilliams' Science...
Transcript of Plate Tectonics - DanielleWilliams' Science...
Plate Tectonics • Topics
1. Lithosphere Definition
a) Types of lithosphere
2. Movement of lithospheric plates
a) Convection Currents
b) Plate Tectonics Theory
3. Plate Boundaries
a) Transform
b) Convergent
i. Continental-Oceanic
ii. Contiental-Continental
iii. Oceanic- Oceanic
c) Divergent Boundaries
4. Features at Plate Boundaries
Lithosphere The outer shell of Earth that is made of rigid crust
and upper mantle
Lithosphere Together the lithospheric crust and upper mantle are broken into moving masses
called tectonic plates
2 Types of Lithosphere Oceanic Crust
Made up of the ocean floor. (Heavier and older than continental)
Continental Crust
Made up of continental landmasses.
Oceanic Crust vs. Continental Crust
How do the lithospheric
plates move?!
2) Convection currents
• Unequal heating from the Earth’s core causes hotter magma to rise and cooler magma to sink down towards the core and heat up
http://youtu.be/ryrXAGY1dmE
https://www.youtube.com/watch?v=ryrXAGY1dmE
Theory of Plate Tectonics (1960)
Earth’s lithosphere
consists of rigid, but moving masses called
tectonic plates
Tectonic Plates
There are 8 major plates and several minor plates
Plate Boundaries
There are 3 main ways that the plates
interact.
Points of interaction are called boundaries
3 Types of Plate
Boundaries…
1. Divergent Boundaries Where two plates are
moving apart,
magma rises and fills space between plates creating new
crust as it cools
CRUST IS GAINED
Divergent boundaries
2.Transform Boundaries
• Plates horizontally slide past one another
3. Convergent Boundaries
When two plates collide
(CRUST IS LOST)
• There are 3 types of
convergent boundaries
1. Continental + Oceanic Convergence
• When an oceanic plate collides with a continental plate. The oceanic plate will subduct under the continental plate.
2. Cont. + Cont. Convergence
• Two continental plates collide, crumple, and uplift
3. Oceanic - Oceanic Convergence
• The older and denser oceanic plate subducts under the lighter oceanic plate forming a trench
Features at Plate Boundaries
Divergent Boundary Features
1. Divergent boundaries
• 1. Mid-ocean ridges: Underwater mountain range
that winds throughout the
Earth’s oceans. It is the 40,000
miles long
New Crust Forms Here As Crust is Pulled Apart
2. Rift Valley: When the crust is pulled or ‘rifted’ apart, valleys form with steep walls
Transform Boundary Features
Transform Boundaries
Earthquakes occur when
stress is too great from plates sliding, causing fracture to form in the crust
Example: San
Andreas Fault
Convergent Boundary Features
Oceanic- Continental Convergent Boundary
Features
(Example: Andes Mountains)
1. Continental Volcanic Arc
2. Trench (subduction zone)
Trench= Deep depression in the ocean floor (caused
by subduction)
3. SUBDUCTION ZONE
Subduction zones occur when a plate sinks beneath another plate
Oceanic- Oceanic Convergent Boundary
Features
1. Volcanic Island Arc Magma rises to the surface along the trench and slowly forms an volcanic island. As the plate moves, a chain of volcanoes will form a volcanic island arc
2. Trench (Subduction zone)
Continental- Continental Convergent
Boundary Features
(Example: Appalachian Mountains and Mt.
Everest)
1. (Folded) Mountains
Appalachian Mountains
Folded Mountains
Appalachian Mountains
As compressional force increases, folded mountains form
Himalayan Mountains
http://www.pbs.org/wgbh/aso/tryit/tectonics/#
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