Seafloor features

1. Prior knowledge check
•Have you ever
walked out into the
ocean water? If
so, do you know
the name of the
part of the Earth
you walked on?
•What happens as
you walk further
out to sea?
•What does
topography mean?

2. Topography
•A detailed map of the physical features of
a region.

3. The Seafloor
•Objective:
•Describe the seafloor features.

4. Continental Shelf and Slope
•The continental shelf
starts at the coastline
and connects to the
continental slope with
a slight decline.
•The continental slope
connects the shelf to
the seafloor and is
typically very steep. It
is carved out by
currents.

5. The Continental Shelf
•The pink region below is the shelf. It can extend
out over 200 miles. Most ocean life lives here.

6. Abyssal Plains
•Seafloor areas that
are relatively flat
because they have
been filled in with
sediment.
•There is very little life
in these areas.

7. Mid-Ocean Ridge
•An underwater mountain chain
•This is where new ocean floor is made by seafloor
spreading
•Remember that seafloor spreading happens at divergent
plate boundaries. The plate move apart allowing magma
to seep up.

8. An Ocean Trench
•Convergent plates form ocean trenches.
•One plate slides under the other.
•Trenches are the deepest places on Earth
•The Marianas Trench is ~ 7 miles deep
•The Grand Canyon, in comparison, is only ~ 1 mile deep

9. Islands

10. Seamounts

11. Wrap-up
•How deep is the Mariana’s Trench?
•What kind of boundary is at an ocean
trench?
•What is the underwater mountain range
where seafloor spreading occurs called?

12. Seafloor Mining
•Petroleum, natural
gas and placer
deposits are mined
from continental
shelves.
•Manganese nodules
are deep-water
deposits that may be
mined in the future.

13. petroleum
•An oily flammable
liquid obtained from
the ground that can
be made into gasoline

14. Manganese
•A metallic chemical
resembling iron but
not magnetic

15. Wrap-up
•How are placer deposits formed?
•What is the name of an underwater
mountain range?