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Divisions of the ocean floor The global ocean is divided in to three major
oceans.1. Atlantic ocean 2. Pacific ocean 3. Indian ocean
Waters in the polar regions are sometimes called oceans.
Sea is the term applied to smaller areas that are partially surrounded by land ( ex: Mediterranean sea, and Caribbean sea)
What is the Ocean Floor?
The ocean floor consist of: Continental Margins ( line that divides
continental and oceanic crust) Deep Ocean Basins ( plains, submerged
volcanic mountains, trenches, Abyssal planes, and flat planes, mid-ocean ridges, and seamounts ).
Sediments ( fragments that result from the breaking of rocks, minerals, and organic mater.)
Continental Margins
Continental Shelf ( edge of a continental covered by shallow ocean water) gently slopes from shorelines. Average depth is 60 meters. The length varies as the continents
shape and size changes. There areas are commonly affected by
changes in sea levels.
Continental Slope Continental slope ( a steep incline
at the edge of a continental shelf.) Boundary between continental
and oceanic crusts. Ocean depth increases several
thousand meters. Submarine Canyons are deep
under water v-shaped valleys. They are associated with
mouths of major rivers. caused by turbidity currents.
Turbidity Currents are dense currents that carries a large amount of sediments, down the continental slopes.
Continental rise the accumulation of sediments at the base of a continental slope.
Deep Ocean Basins Deep ocean basins
Trenches: deepest feature on
the earth’s surface. Long and narrow. The deepest in the
world is the Mariana Trench located in the western pacific ocean, near the island of Guam.
Most trenches located along the pacific ring of fire.
Abyssal Planes( extremely flat areas that lie in the deep ocean basins.) Occurs where ocean’s depth is greater than
4km They cover around ½ of the deep ocean
basins. Mid-Ocean ridges ( Continuous series of
underwater mountains along the ocean floor.) They have narrow depressions ( aka rifts ) They separate at different rates, there for
they create fracture zones. Fracture Zones : faults running perpendicular to
mid-ocean ridges.
Seamounts ( Submerged volcanic mountains ) They are at least
1,000 m high. The seamounts that
are less than 1 km height they are called the abyssal hills.
they are normally associated with hotspots.
Seamounts are also the creator of islands; they rise about the surface ( ex, Hawaii and the canary islands. )
Exploring The Ocean Floor Submersibles- under water
vessels that allow oceanographers to study the depts. of the ocean.
1. Bathysphere- spherical submersibles that remains attached to a research ship to establish communication and support.
2. Bathyscaph- self propelled moving submersible.
Sonar- ( sound navigation system ) method for mapping the ocean floor using sound waves.