Download Inside Earth: Chapter 1

Plate Tectonics
Continental Drift
Crust is broken into plates that are in
constant, very slow motion, driven by
convection currents in the mantle.
• Puzzle-like fit of continents
• Similar fossils on different continents
• Similar rock structures on different
continents
• Warm weather plant fossils and fossil
fuels in arctic areas and glacier deposits
in tropical areas
Divergent
Boundaries
Ocean: Sea Floor Spreading
Ocean plates are being pushed apart by
convection currents and new ocean floor
is made
Crustal Features: Rift Valleys on land
and Mid-Ocean Ridge in ocean
Sea Floor Spreading
Rift Valley on Land
Convergent
Boundaries
•Continental-Continental: huge mountains
Continental-Continental
Convergent
Boundaries
•Continental-Continental: huge mountains
•Continental-Oceanic: Subduction! The
more dense oceanic crust sinks under
the continental. Trenches, mountains, and
volcanoes occur.
Oceanic-Continental
Convergent
Boundaries
•Continental-Continental: huge mountains
•Continental-Oceanic: Subduction! The
more dense oceantic crust sinks under
the continental. Trenches, mountains, and
volcanoes occur.
•Oceanic-Oceanic: Subduction! Very deep
trenches and volcanoes
Oceanic-Oceanic
Transform
Boundaries
• A plate boundary where two plates
move past each other in opposite
directions
• Makes faults and causes earthquakes
Transform Boundaries
Find the Nazca plate on the map. What
direction is it moving?
• The
Nazca
plate is
moving
east
Find the South American plate and
describe its movement.
• The
South
American
plate is
moving
west
What do you think will happen as these
plates continue to move?
As the plates
move, they will
collide
(convergent
boundary)
Since the Nazca
plate is
oceanic crust
and the South
American
plate is
continental
crust, the
Nazca will
plunge
beneath the
South
American
plate