Plate Tectonics. Plate Boundaries Heat Transfer Three types- 1.Conduction 2.Radiation 3.Convection.
Plate Tectonics Plate Boundaries Causes of Plate Tectonics.
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Transcript of Plate Tectonics Plate Boundaries Causes of Plate Tectonics.
Plate TectonicsPlate Tectonics
Plate TectonicsPlate TectonicsPlate BoundariesPlate Boundaries
Causes of Plate TectonicsCauses of Plate Tectonics
Plate TectonicsPlate Tectonics
What is Plate TectonicsWhat is Plate Tectonics
• The Earth’s crust and upper mantle are broken into sections called plates
• Plates move around on top of the mantle like rafts
What is the What is the LithosphereLithosphere??
• The crust and part of the upper mantle = lithosphere–100 km thick –Less dense than the material
below it so it “floats”
What is the What is the AsthenoshereAsthenoshere??
• The plastic layer below the lithosphere = asthenosphere
• The plates of the lithosphere float on the asthenosphere
2 Types of Plates2 Types of Plates
• Ocean plates - plates below the oceans
• Continental plates - plates below the continents
Questions...Questions...• What is the theory of plate tectonics?
• What is the asthenosphere?• What is the connection between the
two?• What are the two types of plates?
Plate BoundariesPlate Boundaries
Plate BoundariesPlate Boundaries
• Divergent Boundary – moving • Convergent Boundary – moving • Transform Fault Boundary – moving
________________________
together
sideways past each other
Divergent BoundariesDivergent Boundaries
• Boundary between two plates that are moving apart or rifting
• RIFTING causes SEAFLOOR
SPREADING
Features of Divergent Features of Divergent BoundariesBoundaries
• Mid-ocean ridges• rift valleys• fissure volcanoes
• subduction zone called a TRENCH
Convergent BoundariesConvergent Boundaries
• Boundaries between two plates that are colliding
• There are 3 types…
Type 1Type 1• Ocean plate colliding with a less
dense continental plate
• Subduction Zone: less dense plate slides under the more dense plate
• VOLCANOES occur at subduction zones
Andes Mountains, Andes Mountains, South AmericaSouth America
Type 2Type 2• Ocean plate colliding with
another ocean plate
• VOLCANOES occur at subduction zones
Aleutian Islands, AlaskaAleutian Islands, Alaska
Type 3Type 3
• A continental plate colliding with another continental plate
• Have Collision Zones:–mountains form.
Transform Fault BoundariesTransform Fault Boundaries
• Boundary between two plates that are sliding past each other
• EARTHQUAKES along faults
San Andreas Fault, CASan Andreas Fault, CA
Questions...Questions...• What are the three types of
boundaries?• What direction do plates go for
each?• Which boundary has a subduction
zone…what occurs at a subduction zone?
Causes of Plate Causes of Plate TectonicsTectonics
What cause plates to move?What cause plates to move?
Convection Currents • Hot magma in the Earth moves
toward the surface, cools, then sinks again.
• Creates convection currents beneath the plates that cause the plates to move.
• The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH
• Subduction Zone: where the less dense plate slides under the more dense plate
• VOLCANOES occur at subduction zones
Explain Pangaea
• This is what type of boundary ?
What are the two types of plates?
Divergent plate boundaries move_______
Tectonic plates move only _______ per year
A. KilometersB. MilesC. CentimetersD. Millimeters
This type of plate movement can result in the formation of mountains and/or volcanoes
What is the lithosphere?
Two transformative plates slide past each other. What geological event is likely to occur?
Questions...Questions...
• How is a convection current formed?
• What are the three types of plate boundaries?
• What causes plates to move?