U5 - Lesson 3: Ocean Features

•A continental shelf is the gently sloping underwater surface extending from the shoreline. Continental shelves contain important mineral deposits, large reservoirs of oil and natural gas, and huge sand and gravel deposits.

•A continental slope is the steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf.

•Trenches form at the sites of plate convergence where one moving plate descends beneath another and drops back into the mantle, which is called subduction. These canyons include Earth’s deepest points.

•The abyssal plain has thick layers of sediment, formed by sunken remains of dead organisms from the surface, which covers these massive, flat plains.

Mid-ocean ridge consists of undersea mountain chains all around the world. These are formed by divergent plates where tectonic plates move apart and new, ocean floor is created.

•Seamounts are underwater mountain. An example is Loihi in Hawaii.

•The Mariana Trench is the deepest known part of the ocean. It is located in the Pacific Ocean and is about 11,000 meters deep.