The Ocean FloorChapter 14

What is Oceanography?

Oceanography science that draws

on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the world ocean

Water on the Earth

61% found in the Northern Hemisphere

81% found in the Southern Hemisphere

71% total on Earth

The Four Oceans

Pacific –largest and the greatest average depth

Atlantic –shallowest Indian Arctic

Mapping the Ocean Floor

Bathymetry measurement of

ocean depths and the charting of the shape or topography of the ocean floor

Mapping the Ocean Floor

Sonar is an acronym for sound navigation and ranging. It is also referred to as echo sounding transmitting sound

waves toward the ocean bottom

Mapping the Ocean Floor

Satellites able to measure

small differences by bouncing microwaves off the ocean surface

Mapping the Ocean Floor

Submersibles are small underwater crafts used for deep-sea research remotely operated

vehicles (ROVs)

Main Ocean Floor Regions

Continental Margin Ocean Basin Floor Mid-Ocean Ridge

Continental Margin

Continental shelf is the gently sloping submerged surface extending from the shoreline mineral deposits, large

reservoirs of oil and natural gas, and huge sand and gravel deposits

Continental slope is the steep gradient that leads to the deep-ocean floor

Continental rise is the gently sloping surface at the base of the continental slope.

Ocean Basin Floor

Trenches form at the sites of plate convergence where one moving plate descends beneath another

Abyssal plain is a very level area of the deep-ocean floor

Seamount is an underwater volcano at least 1000 meters above the deep-ocean floor

Guyot is an eroded, submerged seamount.

Mid-Ocean Ridges

Seafloor spreading process by which plate

tectonics produces new oceanic lithosphere at ocean ridges

New ocean floor is formed Hydrothermal Vents

mineral-rich water is heated by the hot, newly-formed oceanic crust and escapes through cracks in the oceanic crust into surrounding ocean water

Types of Seafloor Sediments

Terrigenous sediments: mineral grains that were eroded

Biogenous sediments: shells and skeletons of marine animals and algae

Hydrogenous sediment: minerals that crystallize directly from ocean water through various chemical reactions

Resources From the Sea

Oil and natural gas main energy products

currently being obtained from the ocean floor

Gas hydrates compact chemical

structures made of water and natural gas

Resources From the Sea

Sand and Gravel Used to fill in recreational

beaches and make concrete Manganese nodules

Extracted to make permanent magnets and engine parts

Evaporative Salts halite—table salt Used for preserving foods

and de-icing roads

Which Ocean Has the Greatest Salt Quantity?

Dead Sea 38% salt content