Plate Tectonics : Different Plate Boundaries Create Different Landforms and Events
Landform:
DEEP-OCEAN TRENCH
Plate Boundary:
Illustration of what is happening
CONVERGENT
Type of Plates:
Oceanic Plate (OP) vs Continental (CP) or Oceanic Plate
How is it formed?
As the MORE DENSE oceanic plate (OP) subducts under
the less dense plate (CP or OP), it pulls the front edge
of the less dense plate down, creating a deep ‘zone’
(TRENCH).
Landform: VOLCANOES
Plate Boundary:
Illustration of what is happening
CONVERGENT
Type of Plates:
Oceanic Plate (OP) vs. Continental Plate (CP)
How is it formed?
The MORE DENSE oceanic plate (OP) subducts under
the less dense continental plate (CP) and is driven
down in to the HOT asthenosphere/mantle. Subducted
plate MELTS due to extreme heat and friction. Melted
plate rises up through the crust, where it reaches the
surface and cools. Happens repeatedly to create large
volcanoes.
Landform:
VOLCANIC ISLAND ARC
Plate Boundary: CONVERGENT
Type of Plates:
Oceanic Plate (OP) vs. Oceanic Plate (OP)
How is it formed?
The same process that forms volcanoes on land.
Subducted OP melts and rises to reach the surface of
the OP. This happens repeatedly, building and building
until the volcano breaks the surface of the water,
creating a chain of islands along the subduction zone.
Illustration of what is happening
Plate Tectonics : Different Plate Boundaries Create Different Landforms and Events
Landform:
Folded MOUNTAINS
Plate Boundary:
Illustration of what is happening
CONVERGENT
Type of Plates:
Continental Plate (CP) vs. Continental Plate (CP)
How is it formed?
Two continental plates collide. Continental plate is not
dense enough to subduct. As a result, the continental
crust folds upward (nowhere else to go) creating a
chain of folded mountains.
Landform: RIFT VALLEY
Illustration of what is happening
Plate Boundary: DIVERGENT
Type of Plates: 2 Continental Plates (CP) pull apart
How is it formed?
Two continental plates (CP) move away from each
other, stretching out the crust, until it begins to
break/fault. As crust is stretched wider, the valley
drops deeper. Eventually can lead to the creation of a
new body of water if low enough.
Landform:
MID-OCEAN RIDGE
Plate Boundary:
Type of Plates:
DIVERGENT
2 Oceanic Plates (OP) pull apart
How is it formed?
Two oceanic plates (OP) move away from each other,
allowing magma to rise up from inside the Earth. The
magma reaches the bottom of the ocean, turns in to
lava and cools (forming new rock). This cycle continues
constantly spreading the sea floor and adding new
material along this chain of mountains.
Sea Floor spreading occurs at these mid-ocean ridges.
Illustration of what is happening