Warm Up 12-5-14

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Warm Up 12-5-14

• 1. What are the four minerals that compose salt
  water?
• 2. What are the three reasons the ocean is
  salty?
• 3. What percentage of a drop of water contains
  sea salt?
• 4. What are the parts of the continental margin?

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Ocean Landforms
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The Ocean Floor
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Revealing the Ocean Floor

• If you could travel to the bottom of the ocean,
  you would see the worlds largest mountain chain
  and canyons much deeper than the Grand Canyon.
• How can the ocean floor be mapped?

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Revealing the Ocean Floor

• Sonar (stands for Sound Navigation and Ranging)
  
• Invented in the 1920s
• Primary instrument for measuring depth
• Reflects sound from ocean floor

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Revealing the Ocean Floor

• Use of satellites for mapping
• Employs satellites equipped with radar altimeters
• Scientists are able to measure the direction and
  speed of ocean currents.
• Measure the different heights of the ocean water
  surface to make maps of ocean floor.
• Can cover more territory using satellites rather
  than ship sonar.

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Continents Edge

• Called the continental margin
• Three parts
• Continental shelf
• Continental slope
• Continental rise

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Continental Shelf

• Begins at the shoreline, Depth can reach 200
  meters, meets the continental slope.
• This is what you walk on at the beach.

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Continental Slope

• Begins at the edge of shelf, Depth ranges from
  200 meters to 4000 meters
• Continent ends at bottom of continental slope

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Continental Rise

• Slopes more gently
• Made of sediments that come off the shelf
• Like underwater avalanches of sediment and
  water

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Abyssal Plain

• Broad, flat portion of the deep-ocean floor.
• Covered with mud and remains of marine organisms.
• Average depth is 4,000 meters

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Mid-Ocean Ridges

• Mountain chains formed where tectonic plates pull
  apart.
• Pulling motion creates cracks in the crust called
  rift zones.
• Rift Valley forms between mountains in the
  mid-ocean ridge.

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Seamounts

• Individual mountains of volcanic material.
• If a seamount builds up above sea level, it
  becomes an island.
• A guyot is a flat-topped seamount.

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Actual footage of an erupting underwater volcano.
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Ocean Trench

• bottomless cracks in the ocean basin (floor).
• Formed where one oceanic plate is forced
  underneath another plate.
• Most famous Marianas Trench

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