Theory of Plate Tectonics:
• Lithosphere is broken up
into many plates that move
• Interactions when the
plates touch, explain
most of the Earth’s land
and ocean features
• Earthquakes can occur at
all plate boundaries
Transform
Divergent
Convergent
• Motion: Plates moving apart
• Features/Processes:
o Sea floor spreading
o Mid-ocean ridge
o Volcanic activity
Ex: Mid-Atlantic Ridge
• Divergent boundary
on a continent
• New ocean forming
DivergBound_PC
• Motion: Plates slide
past each other
• Features/Processes:
Many earthquakes
• Motion: Plates are
pushed together
• Features depend on
which types of plates
are converging
(details below)
• Oceanic subducts under continental because…
o The oceanic crust has a greater density
• Trench is created off the coast
• Volcanic Mountains created on land due to rising magma
• The OLDER oceanic plate will sink beneath the newer
o The older plate is denser b/c it has more time to compact
• Trench is created in between the plates
• A volcanic island arc is created due to rising magma
1. Aleutian Islands, Alaska
3. The Philippines
2. Japan
• Both plates collide and deform
o neither subducts because both plates have similar,
low densities
• The crust thickens as mountains are pushed upward
o metamorphism of rocks takes place from pressure
ConvergMargV2
MotionAtPlate_PC
Explain this diagram:
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