Transcript Journey to the bottom of the ocean (1)

Journey to Bottom of the
Ocean
Click on a feature to go there
or click next to continue with
the journey
We will begin our journey where land
meets the ocean.
Do you know where we are?
Yes. At the beach.
Beaches are the fastest changing part
of the ocean. They change with every
wave.
Back to Map
Continental Shelf
The edge of the continents slope
down from the shore into the ocean.
The part of the continent located under
water is known as the Continental
Shelf.
The continental shelf is rich in
resources such as marine life, minerals
and oil. For this reason, countries
around the world claim the bordering
continental shelf as part of their
territories.
There are several part
to the continental
margin.
– The continental shelf
– The continental slope
– The continental rise
Back to Map
Continental margin cont’d
Continental slope-the steeply inclines section of the
continental margin located between the continental
rise and continental shelf.
Continental rise- the gently sloping section of the
continental margin located between the continental
slope and the abyssal plain.
Continental Slope
The continental slope is a
steep slope that connects
the continental- shelf to
the bottom of the ocean
floor. The slope begins
at a depth of around 460
feet (140 meters).
Back to Map
Volcanic Island Arc
• Volcanic island arcs are a
series of seamount tall enough
to break the sea surface and
form an island.
• The Augustine Island Volcano in
Alaska is an example of a volcanic
arc.
Back to Map
Abyss
• The deepest point in the ocean is
called the abyss
• The Mariana Trench is the deepest
known point in the ocean. It is located
in the western part of the Pacific
Ocean near the fourteen Mariana
Islands.
• The Mariana Trench is a semi-circle
that extends from the northeast to the
southwest for about two thousand five
hundred fifty meters and is seventy
kilometers wide.
Back to Map
Mid Ocean Ridge
•The mid ocean ridge is a series of
mountain ranges on the ocean floor.
•They are more than 84,000 kilometers
(52,000 miles) in length and they extend
through the North and South of the
Atlantic ocean, the Indian Ocean, and the
South Pacific ocean.
•According to the plate tectonics theory,
volcanic rock is added to the sea floor as
the mid-ocean ridge spreads apart.
Back to Map
Abyssal Plain
Abyssal plains are the vast,
flat, sediment-covered
areas of the deep ocean
floor. They are the flattest,
most featureless areas on
Earth. These flat abyssal
plains occur at depths of
over 6,500 ft (1,980 m)
below sea level.
Back to Map
Seamount
• Seamounts are undersea volcanic mountains
rising from the bottom of the sea that do not
break the water's surface
• Seamounts are usually isolated and coneshaped, often volcanic in origin.
• Smaller volcanoes are called sea knolls, and
flat-topped seamounts are called guyots.
Back to Map
Guyot
• Guyots are seamounts that have built
above sea level. Over time erosion by
waves destroyed the top of the seamount
resulting in a flattened shape
Seamount rises
above water
Erosion by waves
flattens the top of the
mount
The seamount
becomes submerged
to form a Guyot
Back to Map
Ocean Trench
• A deep-sea trench is a narrow, elongate,
v-shaped depression in the ocean floor.
• Trenches are the deepest parts of the
ocean, and the lowest points on Earth.
• They reach depths of nearly 7 mi (10 km)
below sea level.
• They can be thousands of miles in length,
yet as little as 5 mi (8 km) in width.
Back to Map
Rift valley
• A rift valley is formed
where two tectonic plates
pull apart from one
another creating a deep
valley.
• Rifts are the opposite of
mountain ranges like the
Alps or the Himalayas
where the plates push
together to create a
mountain.
Back to Map
Deep-sea trench
A long narrow and steep
depression on the ocean floor
that forms during subduction of
two plate, like a deep ditch.
Compare continental and
oceanic landforms
Continental landform
Oceanic landform
Canyon
Trench
Valley
Rift
Volcanic mountain
Seamount
Mountain Range
Mid-ocean ridge
Low hills or plains
Ocean basin (abyssal plains)