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Exploring the Ocean
Why is the ocean difficult to study?
1. It is DEEP! 3.8 km (that’s twice as deep
as the Grand Canyon)
2. It is DARK and COLD! (Only a few
degrees above freezing)
3. It has extreme PRESSURE!
So, how did we map it?
SONAR: Sound
Navigation and
Ranging
Ships bounce sounds
off the ocean floor
and time how long it
takes them to return
to the ship.
What did they find?
1.
2.
3.
4.
5.
6.
Continental Shelf
Continental Slope
Abyssal Plains
Mid-Ocean Ridge
Seamounts
Trenches
Continental Shelf
• Looks like a flat shelf
on the edge of a
continent
• Ranges from 10km350km wide
• Home of many ocean
plants and animals
because sunlight
reaches the bottom.
Continental Slope
• Slope that
reaches from the
edge of the
continental shelf
to the ocean
bottom.
• Steeper than the
continental shelf.
Abyssal Plains
• Flat seafloor area at the bottom of the
continental slope
• 4000-6000km deep
• Covered in decayed animal material
Mid-Ocean Ridge
• Underwater chain
of volcanic
mountains
• Location of
seafloor spreading
Seamounts
• Inactive volcanoes on the ocean floor.
(Some may be active near the mid-ocean
ridge)
• Volcanic Islands: Seamounts that rise above
the water
Trenches
• Mostly found in the Pacific Ocean.
• Deep valley on the seafloor where crust is
returning to the mantle.
• Ex: Marianas Trench = deepest place in
the Pacific Ocean. 11km deep. (Mount
Everest could fit inside it!)
Name the features!
Here are the answers:
•
•
•
•
•
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•
A: Continental Slope
B: Seamounts
C: Abyssal Plain
D: Mid-Ocean Ridge
E: Volcanic Island
F: Continental Shelf
G: Trench