Seafloor spreading Theory

2. is a process that occurs
at mid-ocean ridges,
where new oceanic crust
is formed through
volcanic activity and then
gradually moves away
from the ridge.

4. First proposed in the early
1960s by the American
geologist Harry H. Hess, its
major tenets gave great
support to the theory of
continental drift and provided a
conceptual base for the
development of plate tectonics.

5. Supporting Evidence for Seafloor
Spreading
The rock making up the ocean floor is
considerably younger than the
continents.
For example, the Red Sea was
created as the African plate and the
Arabian plate moved away from each
other.

6. Supporting Evidence for Seafloor
Spreading
Seafloor spreading is also
pulling the continents of
Australia, South America,
and Antarctica away from
each other in the East
Pacific Rise.

7. Supporting Evidence for Seafloor
Spreading
Seafloor spreading is also
pulling the continents of
Australia, South America,
and Antarctica away from
each other in the East
Pacific Rise.

8. Findings that support Seafloor
Spreading Theory:
1. Rocks are younger at the mid-ocean
ridge.
2. Rocks far from the mid-ocean ridge
are older.
3. Sediments are thinner at the ridge.
4. Rocks at the ocean floor are younger
than those at the continents.

10. Q22. What do the
stripes in the paper
represent?
Answer: The stripes
represent the rocks with
normal and reverse
polarities.

12. Q23. What does the middle
slit represent? What occurs
in this region?
Answer: The middle split
represents the mid-ocean
ridge. In this region, the
seafloor spreading occurs.

14. Q24. What is the role of the mid-
ocean ridge in the movement of
lithospheric plates?
Answer: The role of the mid-
ocean ridge in the movement of
lithospheric plates is that it is
where the forces that pushes
the lithosphere came from.

16. Q25. How does the new seafloor form
at the mid-ocean ridge?
Answer:The hot and less dense
material below the Earth’s crust rises
towards the mid-ocean ridge. This
materials flows sideways carrying the
seafloor away from the ridge, and creates
a crack in the crust. The magma flows
out of the crack, cools down and create a
new seafloor.

18. Q26. What process/es
happen at the side
slits?
The side slits is
where subduction
occurs.

21. Q27. Is the Earth getting
larger and wider when plates drift
away from each other?
Explain briefly.
Answer: The Earth is not
getting larger and wider when
plates driftawayfromeach other
because if a new seafloor was
created, the old one was
destructed.

23. The rate of formation of a
new seafloor is not always as
fast as the destruction of the
old seafloor at the subduction
zone.
This explains why the Pacific
Ocean is getting smaller and
why the Atlantic Ocean is
getting wider.