The Ocean FloorChapter 14

Chapter 14.1: The Vast World of Ocean

The Blue Planet 71% of its surface is covered by water.

97% of the water on Earth is salt water

Exploring Oceans

Oceanography: the field of science that studies all aspects of the ocean

The total surface area of Earth = 510 million km²

Continents and islands = 150 million km²

oceans = 360 million km²

If all the water were drained from the ocean, what would the ocean floor look like?

Bathymetry: the measurement of depth of the ocean floorbathos= depth metry= measurement

1872-1876HMS ChallengerFirst voyage to map the ocean floor

Sonar: (Sound Navigation And Ranging) uses electronic signals to determine depth by echo location.

Multibeam Sonar: uses more than one sounds source and listening device to obtain topographic profiles

Satellites: measuring the ocean floor from space, using microwave and radio pulses that are sent back to the satellite, providing detailed images and data.

Submersibles: small underwater crafts used for deep sea research. Collects data about conditions under water including temperature, pressure, sediment samples, pictures and live footage!

http://nautiluslive.org/

Chapter 14.2 Ocean Floor Features

Oceanographers studying the ocean floor have divided it into 3 major regions:

Mid-ocean ridges ocean basin floorContinental margins

Continental margin: the zone of transition between a continent and the adjacent ocean basin floor.

Continental shelf → gently sloping submerged surface, varying widths

Contains:

● mineral deposits

● reservoirs of oil and natural gas

● gravel and sand deposits

Continental slope → steep edge of the continental shelf, boundary between continental and oceanic crust

Submarine canyons → eroded canyons which cut into the continental slope

Turbidity currents → occasional movements of dense sediment-rich water which erode the continental slope

Continental rise → the gradual incline after the continental slope, may be hundreds of meters wide, edge of continental crust

Ocean basin floor: between the continental margin and the mid ocean ridges

Deep-sea trenches→ deepest parts of the ocean, formed at sites of plate convergence

Abyssal plains → deep flat features created by settled deposits

Seamounts & Guyots → submerged volcanic peaks that do not reach the ocean surface

Mid-ocean ridge: interconnected system of underwater mountains developed from newly formed oceanic crust. 1000-4000 km wide

Seafloor spreading occurs at this divergent boundary

Hydrothermal vents appear where mineral rich water is heated by new crust

coral atolls