1. Unit 7 Chapter 23
The Ocean Basin

2. Section 1 The Water Planet
The global ocean contains more than 97% of all the water on or near the Earth’s surface.
Divisions of the Global Oceans
5 Major Oceans
They are the:
Atlantic, Pacific, Indian, Artic and the Southern Oceans.
Seas
A sea is a smaller body of water that may be partially surrounded by land.
Mediterranean Sea
Caribbean Sea
South China Sea

3. Exploration of the Ocean
Oceanography
Oceanography is the scientific study of the ocean using chemistry, biology, physics, geology and other sciences.
In approximately the 1850’s the ocean started to become a popular laboratory
The Birth of Oceanography
In 1855 Matthew F. Murray published the first known textbook on the oceans with information that he collected from Navy records about the currents, winds, depths and weather conditions.
In 1872 the scientists aboard the H.M.S. Challenger made some discoveries that we still use today. In WWII scientists developed sonar recordings and magnetic recordings of the ocean floors.

4. Sonar - Sound Navigation and Ranging
Echo Sounding (sonar)-
Sound signals are sent through the water to the sea floor. By tracking how long it takes for them to bounce back, the depth can be determined.
Satellite Observing-
Bouncing back signals from space can map the area. The waves can not penetrate to the sea floor, but they still can create a high resolution sea floor map based on the height of the sea level.
Submersibles
These are under water research vessels which are piloted by people. Sometimes they will used robotic submersibles to reach areas too dangerous for humans.
Underwater Research
Scientists have found unusual life communities underwater

5. Section 2 Features of the Ocean Floor The ocean floor has 2 major areas; the continental margin and the deep ocean basin.
The Continental Margin
The continental margin is the shallow sea-floor that is located between the shoreline and the deep ocean bottom.
Continental Shelf
The continental shelf extends from the shore line out toward the continental slope.
The Continental Slope and the Continental Rise
Continental Slope
The continental slope begins at the shelf edge where depth increases rapidly.
Continental Rise
The continental rise is several kilometers thick, descends gradually from the continental slope to the ocean floor.
Turbidity Currents
Triggered by earthquakes. They are landslides that go down the continental slope.

6. Deep Ocean Basins Deep ocean basins have distinct features
Deep Ocean Basins Deep ocean basins have distinct features. Some include the highest mountains, and the flattest plains.
Trenches
Trenches are long, narrow depressions located in the deep ocean basins. The Mariana Trench is the Western Pacific is the deepest place on Earth’s Crust
Abyssal Plains
The abyssal plains are considered some of the flattest lands surfaces on Earth; (Argentina’s coastal abyssal plain rises 3 meters over 1300 km). More of the located in the Atlantic Ocean than anywhere else.
Abyssal Hill-
Small rolling hills underwater. In the Atlantic Ocean they run parallel in either side of the mid-ocean ridge.
Mid-Ocean Ridges
Remember the volcano chapter.
Seamounts
Seamounts are submerged volcanic mountains; the beginning of an Island.

7. Section 3 Ocean-Floor Sediment Sediments depend on where they are from and usually are well sorted.
Sources of Deep Ocean Basin Sediments
Samples are usually taken by core sampling. A core sample requires a long tube shoved into the ocean floor and sediments scooped out as a cylindrical piece.
Inorganic Sediments
Sediments produced by non-living things
Biogenic Sediments
Sediments produced by living things
Chemical Deposits
Crystallized dissolved material

8. Physical Classification of Sediments
There are 2 classifications
Mud and Ooze