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

Ocean Landforms

The Ocean Floor

Revealing the Ocean Floor If you could travel to the bottom of the ocean, you would see the world’s largest mountain chain and canyons much deeper than the Grand Canyon. If you could travel to the bottom of the ocean, you would see the world’s largest mountain chain and canyons much deeper than the Grand Canyon. How can the ocean floor be mapped? How can the ocean floor be mapped?

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

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.

Continents Edge Called the continental margin Called the continental margin Three parts Three parts –Continental shelf –Continental slope –Continental rise

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

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

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

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

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

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

Actual footage of an erupting underwater volcano.

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