Download Ocean Topography

Ocean
Topography
What is Ocean Topography?
The shapes, patterns and physical
configuration of the ocean surface.

Side-scan sonar is
used to create an
image of large areas of
the ocean floor.

This tool is used for
mapping the seabed.

In conjunction with
seafloor samples it is
able to show
differences in material
and texture type of the
seabed.
Ocean Basin: Structures
1.Continental Margin:
(near continent)
Continental Shelf
Continental Slope
Continental Rise
Submarine Canyons
2. Deep Ocean Basin:
Abyssal Plains
Oceanic Ridges
Trenches
Seamounts & Guyots
Atolls
3. Others:
Definitions
Continental Shelf –

An extension of the
continent under water.
There is a fairly abrupt
drop off at the edge.
 Has hills, valleys,
canyons and other
features.
 This is very wide off of
Atlantic Canada.

Grand Banks & Scotian Shelf
Continental Slope –
 The portion of the ocean bed between the
edge of the continental shelf and the deepsea floor. The average angle displayed by
the slope is about 5 degrees.
Abyssal Plain –
 The largest portion of the earth’s sea bed.
It is covered with a thick layer of sediment,
beneath which is relatively dense basalt
rock. Vast, empty and usually boring.
Seamounts and Guyots
•
Both are underwater volcanic mountains
that originated at a hotspot or along a
ridge.
•
Guyots: have reached the surface of the
ocean and have flat, eroded tops.
Seamounts: have never reached the
surface, so they have pointy tops.
•
Example : Hawaii
Submarine Canyons
 V-shaped indentations in the continental
shelf, usually ending in a fan shaped
wedge of sediments.
 How do submarine canyons form?

Fast moving currents and underwater landslides.
The Gully



Submarine canyon off Nova Scotia
Marine Protected Area (MPA) because of the rare corals found
there & a resident population of approximately 280 Northern
Bottlenose Whales.
The natural gas pipeline goes right by it…problems?
Mid-Ocean Ridge

A large underwater
mountain chain.

Part of a vast system
extending some 40,000
miles through four of the
world’s oceans.

Caused by divergent
plate boundaries.
NS
Mid-Atlantic
Ridge
Trench –
Deep gap in ocean
floor, formed by
movement of plates.
 Eg:


Mariana Trench is
10,668 meters deep
Deepest areas of the
Earth’s crust.
 90% of trenches are
found around the
Pacific rim.

Atolls

A ring shaped island of coral reefs and coral
debris. These often form over sinking inactive
volcanoes.
Major Sea Floor Structures
H
Major Sea Floor Structures
A. Continental Slope
B.Sea Mount D. Mid Ocean Ridge
E. Island
F. Continental Shelf
C. Abyssal Plain
G. Oceanic Trench
H. Guyot