1. Physical Oceanography
The Ocean Basins
Physical Oceanography

2. Features of the Ocean Basins
Continental margin: portion of ocean made up of continental crust

3. Features of the Ocean Basins
continental shelf: flat part of continental margin covered by shallow ocean water
Formed by changes in sea level
Avg depth = 60 m

4. Shelf Relatively shallow 0 – 200 m
Relatively flat with a gradient of 2 m drop per kilometre

5. Features of the Ocean Basins
continental slope: boundary between continental crust and oceanic crust - The average angle displayed by the slope is about 5 degrees.

6. General Slope Features
Sharp break from the shelf
Angle is gentle, averaging less than 5 degrees
Continues to a depth of 3600 m
Often carved by deep canyons - Hudson Canyon is famous in N.A.

7. Features of the Ocean Basins
continental rise: wedge of sediments that separates slope from ocean floor

8. Rise Slope about ½ degree toward the abyssal plain
Sediment deposition from continent
Range from 100 to 1000 km in width
Only occur along passive margins, often off the mouth of large rivers

9. Features of the Ocean Basins
abyssal plain (floor): very flat areas at depths of 3-5 km

10. Features of the Ocean Basins
submarine canyons: deep, v-shaped valley that cuts through shelf & slope

11. Submarine Canyons V-shaped Hudson Canyon steeper than the Grand Canyon
Form deep sea fans from sediments
Originated from rivers during ice ages

12. The Gully! Submarine canyon off Nova Scotia
Marine protected area because of the rare corals found there
The natural gas pipeline goes right by it…problems?
The Gully

13. Turbidity currents
Turbidity currents are caused by the slumping of sediments from the continental slope.
can travel at over 55 km/h
can spread 700 km+
Can damage underwater pipelines, transatlantic cables

15. Features of the Ocean Basins
mid-ocean ridge: mountain range on ocean floor due to seafloor spreading

16. Features of the Ocean Basins
trench: deep narrow valleys along the edges of subduction zones in the ocean floor; 90% of trenches are found around the Pacific rim.
Marianas Trench in Pacific ocean is the deepest point on earth - 10,668 meters

17. Bathymetric Charts – show the contours and depths of the seafloor topography

19. Features of the Ocean Basins
seamount: underwater volcanic mountain (some more than 1000 m high)

20. Features of the Ocean Basins
guyot: a flat-topped submerged seamount due to erosion

21. Features of the Ocean Basins Atolls
A ring shaped island of coral reefs and coral debris. These often form over sinking inactive volcanoes.

22. Features of the Ocean Basins
coral reef: limestone structures containing shells of animals that surround volcanic islands

23. Features of the Ocean Basins
rift valley: deep crevice in between mountain ranges

26. Which coast has the wider shelf?

27. Another look 