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TRANSFORM PLATE BOUNDARIES
TRANSFORM BOUNDARIES

Transform Boundary - Place
where two plates slide
horizontally past each other
Crust is not created or
destroyed
 Earthquakes occur but NOT
volcanoes

SAN ANDREAS FAULT

San Andreas Fault –
Transform boundary
that extends through
California
Runs right through
San Francisco
 Reason why California
has a lot of
Earthquakes

REASONS FOR PLATE MOVEMENTS

Plate movements are generally caused by 3
mechanisms:
Convection
 Ridge Push
 Slab Pull

CONVECTION CURRENT

A convection current is the reason for plate movements
Hotter parts of the mantle rise while cooler parts sink
 Puts a force on the lithosphere which drives plate movement

RIDGE PUSH

Along mid-ocean ridges new oceanic crust is
created as magma rises from the mantle
As the magma rises this heats up the rocks around the
ridge
 When the rocks cool they then become denser  This
exerts a force on the lithospheric plate and pushes it away
from the plate boundary

SLAB PULL

At subduction zones the denser, oceanic plate is
being pulled down

Because the plate has a high density it helps “pull”
the rest of the plate down as well