QUARTER 1 - LESSON 2 PLATE BOUNDARIES.pdf

Plate boundaries

1. Plate Boundaries
MELC:
1.Describe the different types of
plate boundaries;
2.Explain the different processes
that occur along the plate
boundaries.
Specific objectives:
The learners should be able to:
•describe the different types of plate
boundaries
•differentiate the types of convergent
and divergent boundaries; and
•identify the places/plates that lie on
the different types of boundaries.
EARTH
SCIENCE
GRADE 10

2. MAP OF PLATE
BOUNDARIES
Figure 1

3. TYPES OF
PLATE
BOUNDARIES

4. DIVERGENT
PLATE BOUNDARY
Divergent Boundary is
formed when two tectonic
plates move apart from
each other creating
tension. Molten rocks
called magma rise from the
Earth’s mantle to the
surface. The Earth’s surface
is cool enough to solidify
the magma that rose, thus,
creating new oceanic crust
or seafloor.

5. TYPES OF
DIVERGENT
PLATE
BOUNDARY
▪Oceanic-Oceanic Divergent Plate Boundary
undergoes the process of formation of new crust. The
geologic features or events that may occur are oceanic
ridge and earthquake. Example is the Mid-Atlantic
Ocean Ridge formed between the South American
Plate and the African Plate.

6. TYPES OF
DIVERGENT
PLATE
BOUNDARY
▪Continental-Continental Divergent Plate Boundary
undergoes the process of formation of new crust. The
geologic features or events that may occur are the
linear sea, rift valley, and earthquake. An example is
the Red Sea formed between the Arabian Plate and the
African Plate.

7. Processes and Landforms Along Divergent
Boundary
Divergent plate boundaries mostly happen under
the oceans. As plates pull away from each other, a
vertical space that may extend deep down into the
lowest layer of the crust is created. It is a rift valley.
The force of separation creates a tension zone. A
shallow earthquake may happen with this plate
movement.

8. Processes and Landforms Along Divergent
Boundary

9. Processes and Landforms Along Divergent
Boundary
Plate divergence is believed to be a slow continuous
process. As the plates move away, the gap between
them increases. While this happens, materials from the
mantle may rise, filling up the space. These materials
pile up near the tension zone forming mountain-like
structures called oceanic ridges. But new materials
from the mantle may push the old ones. The filled-up
space between the plates becomes a new seafloor. This
process is known as seafloor spreading.

10. Convergent Boundary is formed
when two plates move toward
each other. This boundary has
three types: Oceanic plate -
Continental plate boundary, Two
Oceanic plates boundary, and
Two Continental plates
boundary.
CONVERGENT
PLATE BOUNDARY

11. TYPES OF
CONVERGENT
PLATE
BOUNDARY
▪Oceanic-Continental Plate Boundary
▪The denser oceanic plate dives beneath the less dense
continental plate. If one of the colliding plates is topped with
oceanic crust, it is forced down into the mantle where it begins
to melt. Subduction is the process by which a plate dives
under a less dense plate. Magma rises into and through the
other plate, solidifying into new crust. Magma formed from
melting plates solidifies into granite, a light-colored, low-
density rock that makes up the continents. Volcanic mountain
arc and trenchare formed. (ex: Cascade Range, Sumatra,
Japan)

12. TYPES OF
CONVERGENT
PLATE
BOUNDARY
▪Continental-Continental Plate Boundary
▪Two thick continental plates collide and buckle into high
mountains. The impact of the two colliding plates buckles the
edge of one or both plates up into a rugged mountain range
(ex: Himalayas Mountain Range).

13. TYPES OF CONVERGENT
PLATE BOUNDARY
▪Oceanic-Oceanic Plate Boundary
▪One oceanic plate dives below another oceanic plate. Volcanic
island chainforms above the zone and trench parallel to the
boundary. (ex: The Marianas). A chain of volcanoes often forms
parallel to the boundary, to the mountain range, and trench. Powerful
earthquakes shake a wide area on both sides of the boundary. The
movement of the ground may cause a disturbance in the ocean. The
water may flip or kick upwards to a few meters high. This is what we
call tsunami, a Japanese term for harbor wave. This event is very
dangerous when it moves inland, destroying lives and properties.

14. Processes and Landforms Along with
Convergence of Plates
A continental crust curves upward on top of the oceanic
crust due to its lesser density. The oceanic crust, due to its
greater density, stays below.

15. Processes and Landforms Along with
Convergence of Plates
When an oceanic crust converges with a continental crust, a
crack between the crusts underwater, called trench, is formed.
Subductionis the process by which a plate dives under a
less dense plate.
It turns into a hot molten material which we call magma.
Due to the heat in the mantle, the magma builds up a
pressure that enables it to push the ground above it. The column
of rising magma is called a mantle plume.
Convergence of oceanic and continental crust

16. Processes and Landforms Along with
Convergence of Plates
When there is volcanic activity such as an eruption, the
ground moves, and so an earthquakeis felt.
Because subduction continues, a group of volcanoes, called
volcanic arc, is formed at the surface of the continental crust
along the boundary where the two crusts converged. The
movement of the ground may cause a disturbance in the ocean.
The water may flip or kick upwards to a few meters high. The
water
may flip or kick upwards to a few meters high. This is what we
call tsunamis, a Japanese term for harbor wave.
Convergence of oceanic and continental crust

17. Processes and Landforms Along with
Convergence of Plates
In the convergence
between two oceanic
crusts, one dives or
subducts under the other.
The figure shows
two crusts underwater, so
they are both oceanic
crusts.
Oceanic Crusts Convergence

18. Processes and Landforms Along with
Convergence of Plates
The front part of the subducting plate becomes
magma upon reaching the mantle. Then it builds up
pressure due to heat, pushes the crust above it, forming
a volcano. This is a continuous process.
This explains why the Philippines is mostly loaded
with volcanoes. The different islands were believed to
have originated from the convergence of two oceanic
crusts.
Oceanic Crusts Convergence

19. Processes and Landforms Along with
Convergence of Plates
Converging continental crusts or
plates result in a collision zone, which
could cause shallow earthquakes. At
that place, a crack called fault is
formed. This type of convergence will
cause no subduction since the two
plates have the same densities. There
would be no volcanoes formed, no
tsunamis. The convergence will result
in a group of high landforms that we
call mountain ranges.
Converging continental crusts

20. TRANSFORM PLATE
BOUNDARY
▪Transform fault boundary is
formed when two plates are
sliding past each other. It is also
called the Strike-slip fault. Rocks
that line the boundary split into
pieces as the plates slip at each
other. A crack is then formed
creating an undersea canyon or
linear fault valley. San Andreas
Fault is an example of this.
(Examples; Alpine Fault )

21. Processes and Landforms Along
Transform Fault Boundary
This is characterized by plates moving horizontally
against each other, producing a crack called fault on the
ground. The force, the plates exert can break the rocks and
other materials under the ground. The shaking usually ends
abruptly. Therefore, it brings about strong earthquakes. The
fault could swallow humans, cars, and buildings. Murky
odorous water from under the ground may spring up from
the fault. Most faults do not totally close when the shaking
ceases since the adjoining edges have already moved
farther from each other.