1. Physical Oceanography Physical Oceanography Ocean Topography

2. What is Topography?  The physical features of an area  The shapes, patterns and physical configuration of the surface of the ocean basins

3.  Side-scan sonar is used to create an image of large areas of the sea floor.  This tool is used for mapping the seabed in conjunction with seafloor samples it is able to show differences in material and texture type of the seabed.

4. The ocean basin: Structures 1. Continental Margin:Continental Shelf (near continent)Continental Slope Continental Rise Submarine Canyons 2. Deep Ocean Basin: Abyssal Plains Oceanic ridges 3. Others: a Trenches b Seamounts and Guyots b Seamounts and Guyots c Atolls c Atolls

5. Instructions:  On the sheet provided, label the diagram and then copy the definitions  You can yell at me tomorrow, but there will be LOTS of notes….then we’ll take a break from notes for a few days!

6. Major Sea Floor Structures: A. Continental Slope B.Sea Mount C. Abyssal Plain D. Mid Ocean Ridge E. IslandF. Continental Shelf G. Oceanic Trench H. Guyot

7. Definitions (YES, COPY)  Continental Shelf – An extention of the continent under water. There is a fairly abrupt drop off at the edge. Has hills, valleys, canyons and other features. This is very wide off of Canada’s maritime provinces. (Grand Banks and Scotian Shelf) Has hills, valleys, canyons and other features. This is very wide off of Canada’s maritime provinces. (Grand Banks and Scotian Shelf)

8.  Continental Slope – The portion of the ocean bed between the edge of the continental shelf and the deep-sea floor. The average angle displayed by the slope is about 5 degrees.  Abyssal Plain – The largest portion of the earth’s sea bed. It is covered with a thick layer of sediment, beneath which is relatively dense basalt rock. Vast, empty and usually boring.

9. Seamounts and Guyots Both are undersea volcanoes that originated at a hotspot or along a ridge Guyots once reached the surface of the ocean and have flat, eroded tops Guyots once reached the surface of the ocean and have flat, eroded tops Seamounts never reached the surface, so they have pointy tops

10. Example:Hawaii!

11. Submarine Canyons  V-shaped indentations in the continental shelf, usually ending in a fan shaped wedge of sediments. How do submarine canyons form?  Thought to be fast moving currents and underwater landslides.

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. Mid-Ocean Ridge  A large underwater mountain chain, part of a cast system extending some 40,000 miles through four of the world’s oceans  Caused by divergent plate boundaries

14. Mid-Atlantic Ridge Us!

15.  Trench – deep gap in ocean floor, formed by movement of plates. Ex: Mariana Trench is 10,668 meters deep They are among the most active areas on Earth.They are the deepest areas of the Earth’s crust. They are among the most active areas on Earth.They are the deepest areas of the Earth’s crust. 90% of trenches are found around the Pacific rim. 90% of trenches are found around the Pacific rim.  Island Arc – A series of islands of volcanic origin, usually found at or near the edge of an ocean basin.

17. Atolls  A ring shaped island of coral reefs and coral debris. These often form over sinking inactive volcanoes.

18. Where are atolls?  Most of the world's atolls are in the Pacific Ocean and Indian Ocean  The Atlantic Ocean has no large groups of atolls other than eight atolls east of Nicaragua