1. Ocean Landforms

2. The Ocean Floor

3. 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.
How can the ocean floor be mapped?

4. 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

9. 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 surface to make maps of ocean floor.
Can cover more territory using satellites rather than ship sonar.

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

13. Continental Shelf Begins at the shoreline
Continues until it begins to slope more steeply downward
Depth can reach 200 meters
This is what you walk on at the beach.

14. Depth ranges from 200 meters to 4000 meters
Continental Slope
Begins at the edge of shelf and continues to flattest part of ocean floor
Depth ranges from 200 meters to 4000 meters
Continent ends at bottom of continental slope

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

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

21. 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.

24. 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.

26. Actual footage of an erupting underwater volcano.

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