Warm Up 12-5-14Warm Up 12-5-14• 1. What are the four minerals that 1. What are the four minerals that

compose salt water?compose salt water?

• 2. What are the three reasons the 2. What are the three reasons the ocean is salty?ocean is salty?

• 3. What percentage of a drop of 3. What percentage of a drop of water contains sea salt?water contains sea salt?

• 4. What are the parts of the 4. What are the parts of the continental margin?continental margin?

Ocean LandformsOcean Landforms

The Ocean FloorThe Ocean Floor

Revealing the Ocean Revealing the Ocean FloorFloor•If you could travel to the If you could travel to the

bottom of the ocean, you would bottom of the ocean, you would see the world’s largest see the world’s largest mountain chain and canyons mountain chain and canyons much deeper than the Grand much deeper than the Grand Canyon.Canyon.

•How can the ocean floor be How can the ocean floor be mapped?mapped?

Revealing the Ocean Revealing the Ocean FloorFloor

SonarSonar (stands for (stands for SoSound und NaNavigation and vigation and RRanging) anging) Invented in the 1920s Invented in the 1920s Primary instrument for Primary instrument for measuring depth measuring depth

Reflects sound from ocean Reflects sound from ocean floor floor

Revealing the Ocean Revealing the Ocean FloorFloor Use of satellites for mapping Use of satellites for mapping Employs satellites equipped with Employs satellites equipped with

radar altimetersradar altimeters Scientists are able to measure the Scientists are able to measure the

direction and speed of ocean direction and speed of ocean currents.currents.

Measure the different heights of the Measure the different heights of the ocean water surface to make maps of ocean water surface to make maps of ocean floor.ocean floor.

Can cover more territory using Can cover more territory using satellites rather than ship sonar. satellites rather than ship sonar.

Continents EdgeContinents Edge•Called the continental marginCalled the continental margin

•Three parts Three parts –Continental shelfContinental shelf–Continental slopeContinental slope–Continental riseContinental rise

Continental ShelfContinental Shelf

•Begins at the shoreline, Begins at the shoreline, Depth can reach 200 Depth can reach 200 meters, meets the meters, meets the continental slope.continental slope.

•This is what you walk This is what you walk on at the beach.on at the beach.

Continental SlopeContinental Slope•Begins at the edge of Begins at the edge of shelf, Depth ranges shelf, Depth ranges from 200 meters to from 200 meters to 4000 meters4000 meters

•Continent ends at Continent ends at bottom of continental bottom of continental slopeslope

Continental RiseContinental Rise•Slopes more gentlySlopes more gently

•Made of sediments that Made of sediments that come off the shelfcome off the shelf

•Like underwater Like underwater avalanches of avalanches of sediment and sediment and waterwater

Abyssal PlainAbyssal Plain

•Broad, flat portion of the Broad, flat portion of the deep-ocean floor.deep-ocean floor.

•Covered with mud and Covered with mud and remains of marine remains of marine organisms.organisms.

•Average depth is 4,000 Average depth is 4,000 metersmeters

Mid-Ocean RidgesMid-Ocean Ridges

•Mountain chains formed where Mountain chains formed where tectonic plates pull apart.tectonic plates pull apart.

•Pulling motion creates cracks Pulling motion creates cracks in the crust called rift zones.in the crust called rift zones.

•Rift Valley forms between Rift Valley forms between mountains in the mid-ocean mountains in the mid-ocean ridge.ridge.

SeamountsSeamounts•Individual mountains of Individual mountains of volcanic material.volcanic material.

•If a seamount builds up If a seamount builds up above sea level, it above sea level, it becomes an island.becomes an island.

•A guyot is a flat-topped A guyot is a flat-topped seamount.seamount.

Actual footage of an erupting underwater volcano.

Ocean TrenchOcean Trench•bottomless cracks in the bottomless cracks in the ocean basin (floor).ocean basin (floor).

•Formed where one oceanic Formed where one oceanic plate is forced underneath plate is forced underneath another plate.another plate.

•Most famous: Most famous: Marianas TrenchMarianas Trench