Transcript Ocean Topography presentation

Physical
Oceanography
Ocean Topography
What is Topography?
 The
 The
physical features of an area
shapes, patterns and physical
configuration of the surface of the
ocean basins
 Side-scan
sonar is
used to create an
image of large areas
of the sea 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.
The ocean basin: Structures
1.
Continental Margin:
(near continent)
2. Deep Ocean Basin:
Continental Shelf
Continental Slope
Continental Rise
Submarine Canyons
Abyssal Plains
Oceanic ridges
3. Others: a Trenches
b Seamounts and Guyots
c Atolls
Instructions:
 On
the sheet provided, label the diagram
and then copy the definitions
 You
can yell at me tomorrow, but there will
be LOTS of notes….then we’ll take a
break from notes for a few days!
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
Definitions (YES, COPY)
Shelf – An
extention 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 Canada’s
maritime provinces.
(Grand Banks and Scotian
Shelf)
 Continental
Slope – The portion of the
ocean bed between the edge of the
continental shelf and the deep-sea floor.
The average angle displayed by the slope
is about 5 degrees.
 Continental
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.
 Abyssal
Seamounts and Guyots
Both are undersea volcanoes that originated at a
hotspot or along a ridge
Guyots once reached the surface of the ocean
and have flat, eroded tops
Seamounts 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?
 Thought to be fast moving currents and
underwater landslides.
The Gully!



Submarine canyon off Nova Scotia
Marine protected area because of the rare corals found there
The natural gas pipeline goes right by it…problems?
The Gully
Mid-Ocean Ridge

A large underwater
mountain chain, part of a
cast system extending
some 40,000 miles
through four of the
world’s oceans

Caused by divergent
plate boundaries
Us!
Mid-Atlantic
Ridge
 Trench
– deep gap in ocean floor, formed by
movement of plates. Ex: Mariana Trench is
10,668 meters deep
They are among the most active areas on
Earth.They are the deepest areas of the
Earth’s crust.
90% of trenches are found around the Pacific
rim.
Arc – A series of islands of volcanic
origin, usually found at or near the edge of
an ocean basin.
 Island
Atolls

A ring shaped island of coral reefs and coral debris.
These often form over sinking inactive volcanoes.
Where are atolls?
 Most
of the world's atolls are in the Pacific
Ocean and Indian Ocean
 The Atlantic Ocean has no large groups of
atolls other than eight atolls east of
Nicaragua