Bellringer Pretend you have walked off the edge of North America and into the depths of the Atlantic Ocean. As you walk along the ocean floor toward Europe, what do you see? Draw the ocean floor as you imagined it. Illustrate your answer in your science notebook.
Ms. Ginnever, Student Teacher 7 th Science
Studying the Ocean Floor Satellite 1978 scientists launched the satellite Seasat Focused on the ocean, sending images back to Earth to measure direction and speed of ocean currents. Geosat Used to be a top-secret military satellite Measures changed in ocean surface and underwater features, such as mountains and trenches. Sonar Sound navigation by ranging
The longer it takes for the sound to bounce off the ocean floor and return to the ship, the deeper the floor is in that spot.
Satellite image
Revealing the Ocean Floor
Continental Margin
Continental Shelf Begins at the shoreline and slopes towards the open ocean It continues until the ocean floor slopes more steeply downward The depth can reach 200 meters Continental Slope Begins at the edge of the continental shelf and continues down to the flattest part of the ocean floor The depth ranges from 200 meters to 4,000 meters
Continental Margin Continental Rise Is the base of the continental slope and is made up of large piles of sediment It’s the boundary between the continental margin and the deep-ocean basin
Deep Ocean Basin
Rift Valley
Deep Ocean Basin Abyssal Plain Depth of 4,000 meters Broad flat part of the deep-ocean basin Covered by mud and remains of marine organisms Mid-Ocean Ridges Mountain chains that form where tectonic plates pull apart Pulling action creates cracks called rift zones. As rifts form magma rises to fill in the cracks which causes the rifts to expand and rise to create the ridges
Deep Ocean Basin Rift Valley The area between the ridges in the rift zone Ocean Trenches Huge cracks in the deep ocean basin Ocean trenches are formed when the oceanic plate is pushed below the continental plate or another oceanic plate Seamounts Individual mountains of volcanic material Formed when magma pushes it’s way between tectonic plates If a seamount builds up above sea level it becomes a volcanic island
Exploring with Underwater Vessels Piloted Vessels Alvin Deepworker 2o45I4