Transcript Continental Shelf

What I will learn…
• (3-1) Describe how technologies help
scientists map the ocean floor
• (3-2) Identify the following features on a
sea floor map: continental shelf,
continental slope, continental rise,
trenches, plains, sea mounts, guyots, and
mid-ocean ridges.
Think About It
• At its deepest point, the Puerto Rico
Trench in the Atlantic Ocean is 28,231 feet
(more than 5 miles deep). Because of the
tremendous pressure, it is not possible for
humans to personally explore this deep
into the ocean.
Key Question
 How do scientists know what the bottom of
the ocean floor looks like? How do they
know how deep the oceans are?
• I think… because…
Investigating the Oceans
• Earth = Blue Planet
– 71% of planet covered with water
– 97% of that water is found in oceans
• Oceanography = Study of planet’s oceans
• Ocean Geography
– Four major ocean basins
•
•
•
•
Atlantic
Pacific – largest and deepest
Indian
Arctic – smallest and most shallow
• Tools for measuring the depth of the
ocean floor
– Sonar
– Satellites
– Submersibles
• Sonar = Sound Navigation and Ranging
– Sound waves sent to bottom of ocean
– Sound waves reflected back to a receiver
– Based on time it takes for wave to be
reflected, the distance to ocean floor can be
measured
• Satellites
– Can measure the differences in the seasurface height by bouncing microwaves off
the ocean’s surface
– Underwater mountains cause sea surface
level to be higher
– Canyons & trenches
cause sea surface
to be lower
• Submersibles
– Underwater vessel that can be used for deep
sea research
– Can be manned or unmanned (ROV)
– Carry scientific instruments to learn about
ocean
• The ocean floor is NOT flat!
–3 Major Regions
• Continental Margins
• Ocean Basin Floor
• Mid-Ocean Ridge
A=Continental Shelf= Gently sloping
area that extends from the shoreline
B=Continental Slope= Steep slope that
marks boundary between continental
crust and oceanic crust
C=Deep-Ocean Trench= Deepest part
of the ocean; form when one plate
moves underneath another plate
D=Mid-Ocean Ridge= Underwater
mountain system; sea floor spreads
apart; formed new ocean crust
E=Volcanic Island= Seamount that
reaches the surface of the ocean
F=Seamount= Underwater volcano
G=Abyssal Plain= flat feature on
bottom of ocean floor; most level
places on Earth
Cape May, NJ
Cape Roca,
Portugal
Investigate Part B:
Mapping the Ocean Floor
Distance
0
0
-500
Depth
-1000
-1500
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-2500
-3000
-3500
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Direction #5
• Color the ocean crust (sea floor) brown
• Color the water areas (not the ocean floor)
on your graph:
– Depth between 0-110 light green
– Depth between 110-1100 light blue
– Depth between 1100 – ocean floor dark blue
Mapping the Ocean Floor
Azores, Portugal
Cape Roca,
Portugal
Cape
500 May, NJ
0
0
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-500
-1000
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-3500
Mid Atlantic Ridge
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Mapping the Ocean Floor
Continental Shelf
Gently sloping area that
Abyssal Plain
extends from the shoreline
Continental Slope
Deep extremely flat features
500
Steep slope that marks boundary
between continental crust and
0
oceanic crust
0
500
1000
1500
2000
-500
-1000
-1500
-2000
-2500
Seamount
-3000
-3500
Underwater volcanic peaks
2500
3000
3500
4000
Azores, Portugal
Cape May, NJ
Cape Roca,
Portugal
Mid Atlantic Ridge
Continental Shelf
Gently sloping area that
extends from the shoreline
Continental Slope
Steep slope that marks boundary
between continental crust and
oceanic crust
Seamount
Underwater volcanic peaks