Download The Theory of Plate Tectonics

The Theory of
Plate Tectonics
The lithosphere is
divided into separate
sections called plates.
The plates carry
continents and ocean
crust or both.
A Theory of Plate Motion
 J.Tuzo
Wilson, a Canadian scientist,
combined sea floor spreading, Earth’s
plates and continental drift into a
single theory.
 Scientific theory is a well tested
concept that explains a wide range of
observations.
 Plate tectonics is a theory that states
the pieces of Earth’s lithosphere are
in constant slow motion driven by
convection currents in the mantle.
 Plate
Tectonic Theory explains
the formation, movement, and
subduction of Earth’s plates.
PLATE BOUNDARIES:
 The edges of different pieces of
the lithosphere meet at lines
called plate boundaries.
 Faults- breaks in Earth’s crust,
form at boundaries.
There
three types of plate
boundaries: Transform,
Divergent, and
Convergent.
Transform Boundaries
A
place where
two plates slip
by each other,
moving in
opposite
directions.
 Earthquakes
occur at these
boundaries.
Divergent Boundaries
 The
place where
two plates move
apart or diverge.
 When a
divergent
boundary occurs
on land a Rift
Valley, a deep
valley, occurs.
Convergent Boundary
 The
place where
two plates come
together, or
converge.
 When two plates
collide, the plate
that is most
dense will sink
beneath the
other.
The Continents Slow Dance
The
plates move from about
one to ten centimeters a
year.
The North American and the
Eurasian plates move about
2.5 cm. a year.