Plate Boundaries Earth’s crust plus the upper mantle forms the lithosphere. Earth’s lithosphere is broken in a number of different pieces. How these pieces move and interact is what plate tectonics is all about.
Jan 18, 2016
Plate Boundaries
Earth’s crust plus the upper mantle forms the lithosphere.
Earth’s lithosphere is broken in a number of different pieces.
How these pieces move and interact is what plate tectonics is all about.
Convergent boundaries
• When 2 plates collide with one another.
Convergent boundaries
• When oceanic plates collide, one subducts under the other.
• This forms a valley in the ocean floor called a trench.
An example of a trench is the Marianas Trench.
Convergent boundaries
When continental plates collide mountains form.
Convergent boundaries
• What happens if an oceanic plate and a continental plate collide?
• Which plate would subduct?
• The oceanic plate must subduct under the continental plate.
• A continental plate is simply too buoyant to subduct under an oceanic plate.
Divergent boundariesA divergent boundary is the line between two
plates where they are moving apart.
Divergent boundaries
• Divergent boundaries can be found on continents as rift valleys.
• When a rift valley forms on land, it may eventually split the landmass.
Divergent boundaries
• Divergent boundaries can also be found in the ocean
• Sea floor spreading occurs at a mid ocean ridge.
Plate boundaries
• An edge of a lithospheric plate that slides by another plate is called a transform fault boundary.
Transform fault boundaries• When seen from
above, the feature will appear to make a zig-zag.
• Causes Earthquakes
• San Andreas Fault
Earth’s lithospheric plates• Can you identify the three types of plate
boundaries labeled A, B, and C?.