The document discusses plate tectonics and describes how the Earth's lithosphere is broken into plates that move over time. It explains that plate tectonics built upon Alfred Wegener's theory of continental drift, which proposed that the continents were once joined together in a supercontinent called Pangaea. There are nine major tectonic plates and three types of plate boundaries - divergent boundaries which create mid-ocean ridges and rift valleys, convergent boundaries which cause subduction and mountain building, and transform boundaries where plates slide past each other like the San Andreas Fault. Convection currents in the Earth's mantle provide the driving force for plate movements.

1. TECTONIC
PLATES

2. WHAT IS
PLATE
TECTONICS ?

3. •Plate tectonics holds theory of the outermost
rigid layer of the earth (the lithosphere) is broken
into several segments called “PLATES” , and these
lithospheric plates are in motion.
PLATES
PLATES

5. •Plate tectonics is the modern version of
CONTINENTAL DRIFT.
•Continental drift is a theory first proposed by
ALFRED WEGENER, a German meteorologist in
1912. The theory explains that the continents
today had been once joined together in a single
landmass called ‘supercontinent’ PANGAEA 200
million years ago.
•Wegener hypothesized that Pangaea broke apart
into smaller pieces that slowly drifted away from
each other.

6. Continental Drift
PANGAEA
“All The Earth”
theory

7. THE SUPERCONTINENT PANGAEA

8. •There are big and smaller plates throughout the world.
•The nine (9) major plates are;
1. North – American Plate 6. Australian Plate
2.Pacific Plate 7. Indian Plate
3.Eurasian Plate 8. South American Plate
4.African Plate 9. Antarctic Plate
5.Indo – Australian

9. MAP OF THE EARTH’S PLATES

11. - two plates moving away from each other
.
Continental Plate
Continental Plate
Rift Valley
Lithosphere

13. When oceanic plates
move apart from each
other it creates;
 Oceanic Ridge
 Volcanic Activity in
the form of fissure
eruptions
 Shallow earthquake
activity
 Creation of new
seafloor and
widening ocean
basin.
Example:
The Mid Atlantic Ridge
Oceanic Ridge

14. MID -
ATLANTIC
RIDGE

15. When continental
plates moves apart
form each other it
creates;
 Rift valley
(sometimes
occupied by long
linear lakes or a
shallow arm of
the ocean).
Example:
The Red Sea

16. THE RED SEA
- Formed by a divergent
boundary

17. - two plates moving/colliding with each other
Continental Plate
Continental Plate
Lithosphere
Lithosphere

18. There are three scenarios that may
happen along the convergent boundary;

19. Two continental
plates may collide
• When two
continental plate
collides, the rocks
that are caught
between are
squeezed, crumpled
and lifted up. In the
process mountains
are built.
• Continental to
continental plate
collisions are
MOUNTAIN –

20. THE HIMALAYAN MOUNTAINS

21. Two oceanic plates
may collide
- When two oceanic
plates collide, one of
the plates, whichever is
denser dives under the
other. This diving
process is called
subduction.
- SUBDUCTION leads to
melting of rocks in
mantle. The magma will
then rise to the earth’s
surface to form a chain
of volcanic islands called
island arc. (Ex. The

22. AERIAL VIEW OF “ALEUTIAN ISLANDS”. AN EXAMPLE OF ISLAND ARC CAUSED BY
THE COLLISION OF TWO OCEANIC PLATES.

23. Continental Plate and
Oceanic Plate may
collide
- When a continental and
oceanic plate collide, the
oceanic plate subducts or
dives under the continental
plate.
- This also produces
trenches and initiates
volcanism.
- A good example of this
type of boundary exists in
south America, where
subduction along Peru –
Chile Trench feeds the
volcanoes in the Andes

24. ONE OF THE ACTIVE VOLCANOES OF THE ANDES MOUNTAIN
RANGES. “THE CALBUCO”
An example of the
subduction effect
along Peru – Chile
trench. The
subduction feds this
volcano that causes it
to erupt.

25. - the plates are sliding past each other.
Continental Plate
Continental Plate
Lithosphere
Lithosphere

26. “SAN ANDREAS FAULT”, THE FAMOUS TRANSFORM BOUNDARY LOCATED
IN CALIFORNIA AND IT’S EVIDENCES

27. WHY
THE
LITOSPHERE
MOVES ?

28. CONVECTION in the mantle is probably the fundamental
driving mechanism responsible for the plate motion.
CONVECTION – is the process of rising and sinking of
rock materials in the mantle. The hot rock materials rise
( because of lesser density ) while cooler rock materials
sink ( because of greater density ).
CONVECTION