Features of the Ocean Floor Example For Students

Features of the Ocean Floor Question Answer The edge of a continent where the land interacts with the ocean. The transition from land to deep sea, from continental crust to oceanic crust that consists of the continental shelf, slope rise. Continental Margin Contains active geological areas such as subduction, volcanoes, earthquakes. Has a very narrow continental shelf that is less stable with a very steep continental slope and little or no continental rise. Occurs more on the West Coast. Active Continental Margin Is a non-geologically active area that has wide continental shelves that are more stable with gradual sloping continental slopes and a well developed continental rise. Occurs in the East Coast. Passive Continental Margin A gently sloping submerged plain that surrounds all continents. It can be narrow or wide, from the beach out to the shelf break. Continental Shelf The area where the seafloor drops steeply from the continental shelf to the ocean floor. Continental Slope The area where sediments from continents pile up at the base of the continental slope. Continental Rise Steep V shaped cuts through the continental slops with turbidity currents, or under sea mudslides, carve valleys into the shelf slope creating deep sea fans. Submarine Canyons Small, submerged volcanic mountains that are taller than 1 km and rise above the ocean surface to form islands. Seamounts These are eroded seamount islands that have become flattened and are beneath the ocean surface. Guyots These are long, narrow, steep depressions in the ocean floor that form the deepest parts of the ocean and are mainly found in the Pacific Ocean basin. They form at convergent tectonic plate boundaries (subduction zones). Ocean trenches The deepest ocean trench. Mariana trench This is the vast, flat seafloor area at a depth of 10,000 to 20,000 ft. Larger ones are hundreds of miles wide and thousands of miles long. Abyssal Plain This global system is the largest single volcanic feature on the Earth. It is the site of focused volcanic activity. These occur at divergent tectonic plate boundaries when 2 plates are moving away from each other. Mid-Ocean Ridge This is a depression that forms at the crest of the mid-ocean ridge. Magma comes up out of a crack in the sea floor, where new crust is continually being created. Rift Valley Hot springs or geysers on oceanic ridges that occur when sea water seeps into the ocean floor and is superheated by the underlying magma. It mixes with minerals and gases before escaping upwards through cracks in the crust. Hydrothermal vents Unstable areas of mid-ocean ridge where fractures can form when large sections of the ridge slide past each other. Transform faults These are areas of very rough, steep topography that are created from transform faults that run perpendicular across ridges. Fracture zones