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Exploring the Ocean
• Since ancient times
people have studied the
ocean such as waters
and ocean floor
• It provides food and
services, and serves as a
route for trade and
travel
The World’s Oceans
• 71% of the Earth’s surface is covered by ocean
water.
• The oceans contain 97% of the earth’s water.
• All the oceans and seas are actually one
continuous body of water.
Oceans
• The oceans are the Atlantic, Pacific, Indian.
Arctic and Southern.
• The Pacific Ocean is the largest ocean.
• The area and volume of the Pacific Ocean are
greater than the Atlantic and Indian
combined.
Seas
• A sea is a part of an ocean that is nearly
surrounded by water.
• The Mediterranean, Arctic and Black Sea are
really part of the Atlantic Ocean.
Ocean Floor Makeup
• The ocean floor has higher mountains, deeper
canyons, and larger flatter plains. Earthquakes
occur more often.
• The rocks are very different.
• The crust is thinner
Edges of the Continents
• The shoreline is a boundary between where the
land and the ocean meet.
• The topography of the ocean floor is different
from the topography of the continents
Continental Margin
• The area where the underwater edge of a
continent meets the ocean floor is called a
continental margin.
• A continental margin consists of a continental
shelf, a continental slope and a continental
rise.
Continental shelf
• The flat part of a continental margin that
is covered by shallow area of the ocean
floor that extends outward from the
edge of a continent is called a
continental shelf.
Continental shelf
• Depth of 130 meters and gets steeper
• A continental shelf slopes gently from
the shoreline.
• The width of the continental shelf
varies.
• Large mineral, oil and natural gas
deposits are found here.
Continental Slope
Continental Slope
• The steep edge of the continental
shelf
• At the edge of the continental shelf,
the ocean floor plunges steeply 4 to
5 kilometers.
• A continental slope marks the
boundary between the crust of the
continent and the crust of the ocean
floor
Continental Rise
• Separating a continental slope from the ocean
floor is a continental rise.
• A continental rise is made of large amount of
sediments, rocks, plants and animals.
• Sometimes the sediments are carried down
the slope in masses of flowing water called
turbidity currents, like an underwater
avalanche.
Abyssal Plain
Abyssal Plains
• Large, flat areas on the ocean floor are called
abyssal plains.
• The abyssal plains are larger in the Atlantic
and Indian than in the Pacific due to the
deposition of sediments by large rivers.
• The Pacific Ocean has large cracks that trap
sediments and result in smaller abyssal plains.
Abyssal Plains
• Abyssal plains close to the continent are made
of mud, sand and silt.
• Farther out on the abyssal plains, some of
them contain the remains of tiny organisms
that form ooze.
• Where ocean life is not abundant, the floor of
the ocean is covered with red clay
Plates
• Pieces of earths crust along with parts of the upper
mantle are called plates.
• The plates move at an average speed of several
centimeters per year-barely faster than your
fingernails grow
• This is what
shaped the dramatic
features of the ocean,
such as mountains
and trenches
Seafloor Spreading
• Mid ocean ridge is along
boundaries of plates that are
moving apart or Diverging
adding a new strip of rock to
the ocean floor
• Magma squeezes up through
cracks
• Magma hardens
• Seafloor spreading is what
produced our ocean floor
• When plates come together
or Converge, one plate sinks
under the other
Mid Ocean Ridge
Mid ocean Ridges
• The mid ocean ridges form an almost
continuous mountain belt that extends from
the Arctic Ocean down through the middle of
the Atlantic Ocean around Africa into the
Indian Ocean and across the Pacific Ocean ,
much as the line of stitches winds around a
baseball.
• In the Atlantic it is called the mid-Atlantic
Ridge and in the Pacific, the Pacific-Antarctica
Ridge.
Formation of Mid ocean Ridges
• Mountain ranges on land are formed when
the Earth’s crust folds and is squeezed
together.
• Mid ocean ridges are areas where molten
material from deep within the Earth flows up
to the surface and cools and forms new crust.
• Has 2 parallel chains of mountains separated
by valley and trenches
Submarine Canyons
• In many areas, submarine canyons cut
through a continental shelf and slope.
• They are deep, V-shaped valleys that have
been cut in the rock, possibly by turbidity
currents.
• The Monterey Submarine Canyon(2000
meters) is deeper than the Grand Canyon.
Rifts
• Running along the middle of the mid ocean
ridges between the rows of parallel mountains
are deep crevices or rifts.
• Rifts are areas of great earthquake and
volcanic activity.
Trenches
• Trenches are the
deepest parts of the
ocean found along the
edge of the ocean floor.
• Is a steep sided canyon
in the ocean floor
• The Mariana Trench in
the Pacific Ocean
contains the deepest
spot on Earth- the
Challenger Deep.
Mariana Trench
• The Mariana Trench is 2, 542 km (1,580 miles) long
(more than five times the length of the Grand
Canyon) and 69 km (43 miles) wide
• The Challenger Deep is 11,033 meters (36,201
feet), almost 7 miles
• If Mount Everest, which is the tallest point on Earth
at 8,850 meters (29,035 feet), were set in the
Mariana Trench, there would still be 2,183 meters
(7,166 feet or about 2 miles) of water left above it.
• http://deepseachallenge.com/the-expedition/mariana-trench/
• https://www.youtube.com/watch?v=9FYKLS7xjpg
Mariana
Trench