(Modified from) Chapter 3
Marine Provinces
Essentials of Oceanography
7th Edition
Learning Targets
Be able to…
Explain bathymetry
Describe features of the sea floor
Identify a passive vs. an active continental margin
Bathymetry
Bathymetry is
the measurement of ocean depths and the
charting of the shape or topography of the
ocean floor
Bathymetric techniques
Side-scan
sonar uses a
“fish” towed
behind a ship
to give a more
detailed
picture of the
sea floor
Figure 3-2
Bathymetric techniques
Satellites
measure sea
surface
elevation,
which mimics
sea floor
bathymetry
Figure 3D
The hypsographic curve
The
hypsographic
curve shows
the relationship
between the
height of the
land and the
depth of the
oceans
Figure 3-4
Major regions of the North
Atlantic Ocean floor
Continental
margin
Ocean basin
floor
Mid-ocean
ridge
Figure 3-5
Passive versus active continental
margins
Passive margin
No plate
boundary
Shelf
Slope
Rise
Figure 3-6
Passive versus active continental
margins
Active margin
Plate boundary
Convergent



Shelf
Slope (steep)
Trench
Transform

Continental
borderland
Figure 3-6
Abyssal plains
Deep flat areas
formed by suspension
settling
Volcanic peaks poke
through the sediment
Abyssal hills
(seaknolls)
Seamounts
Tablemounts (guyots)
Figure 3-9
Ocean trenches
Deepest parts of the
ocean
Formed by plate
convergence
Most trenches are in
the Pacific Ocean
Associated with
volcanic arcs
Island arc
Continental arc
Figure 3-10
The mid-ocean ridge
Circles the globe like the seam of a baseball
Mostly traverses the middle of ocean basins
A topographically high mountain range
Entirely volcanic in origin
Associated with plate divergence
In the Pacific Ocean, called the East Pacific Rise
In the Atlantic Ocean, called the Mid-Atlantic Ridge
Internet flybys of portions of the mid-ocean ridge
Features of the mid-ocean ridge
Rift valleys
Form when
plates split
apart
Downdropped areas
associated
with faults
and
earthquakes
Figure 3-13
Features of the mid-ocean ridge
Pillow lava
Forms when hot
lava comes into
contact with cold
seawater and
quickly cools
Basalt
composition
Figure 3-14
Features of the mid-ocean ridge
Hydrothermal vents
Form when seawater
is heated by magma
Black smokers emit
hot water through
chimneys
Associated with metal
sulfide deposits and
unusual lifeforms
Figure 3-15
Learning Targets
Be able to…
Explain bathymetry
Describe features of the sea floor
Identify a passive vs. an active continental margin
End of Chapter 3
Essentials of Oceanography
7th Edition