Oceanography Ocean Floor Features Ocean Circulation Waves and

Oceanography • Ocean Floor Features • Ocean Circulation • Waves and Tides

Oceans • https: //www. youtube. com/watch? v=3 GRA 7 il. M 708

Ocean Topography

How do we get the information about the ocean floor? • Sonar – Boats using sonar to map the ocean floor as they pass over it. • Boats have to go in set patterns going back and forth just like you would mow a lawn to make sure it covers everything • Slow process • Satellites • Measure the ocean surface height as small as 3 -6 cm • These can be affected by features under the water, help to verify sonar readings • Submersibles • Small underwater craft that can be manned or unmanned. • Give a visual as well as other readings to verify the findings in detail

Sonar • https: //www. youtube. com/watch? v=-f. AAx. EIFe. LU

Starting at the beach • The area where a continental plate meets an oceanic plate is called a Continental Margin. • Most ocean features will be in this range due to plate tectonics

Beach to water • Continental Shelf • Gently sloped underwater surface • Some areas it is very short in width (convergent boundaries) while others can be quite large • Fairly flat, only dropping at about 2 meters per KM (6 feet per mile) • Great source of minerals, oil, natural gas, sand, gravel, and fishing

Continental Slope • The edge of the continental crust where it goes down to the oceanic crust • Much steeper where the water gets deep quickly • Can contain deep cuts called Submarine Canyons that can be ends of ancient rivers • They can also be formed from Turbidity Currents that have a lot of sediment moving at once • Because it is more muddy than normal seawater it is more dense and flows down the side eroding it

Continental Rise • Slope becomes much smaller as the ocean floor starts to flatten • No trenches in this area • Continental Slope leading down can be nearly 20 km wide but the rise can be 100’s of km wide

Ocean Basin Floor • 30% of Earth’s surface is ocean floor • Abyssal Plains • Very deep very flat areas after the continental rise • Probably the flattest places on earth due to lots of sediment settling there at a fairly even rate • Mid-Ocean Ridges • Occur all around the Earth due to seafloor spreading • Divergent oceanic plates allow magma to come up and form ridges and create new ocean floor

Ocean Topography