Active and also Passive continent Margins
The continental margins are among the three major zones the the s floor, the various other two gift deep-ocean basins and also mid-ocean ridges. The continental margins room the shallow water areas found in proximity come continents. The continent margins are the zone of the ocean floor that different the slim oceanic crust from thick continental crust. Together, the continental shelf, continental slope, and also continental increase are dubbed the continental margin. Continent margins constitute around 28% that the oceanic area.
An energetic continental margin is uncovered on the top edge that the continent wherein subduction occurs. Active continental spare are typically narrow from coastline to shelf break, through steep descents right into trenches. Terrific example is the west shore of southern America. Active margins are generally the web page of tectonic activity: earthquakes, volcanoes, mountain building, and also the formation of new igneous rock. These space often significant by uplift and volcanic mountain belts on the continent plate, and also by island-arc chain on the oceanic plate. Less often there is a strike-slip fault, comparable to the one that defines the southern coast of western Africa. Many of the east Indian Ocean and also nearly every one of the Pacific s margin are examples of active margins. Active margins can be convergent or change margins.
A passive margin is the transition between oceanic and continental lithosphere the is not an energetic plate margin. A passive margin creates by sedimentation above an ancient rift, now significant by transitional lithosphere. Continental rifting creates brand-new ocean basins. Eventually the continent rift forms a mid-oceanic ridge and also the locus of expansion moves away from the continent-ocean boundary. The transition between the continental and also oceanic crust that was originally developed by rifting is well-known as a passive margin. Passive margins are found at every ocean and continent boundary that is not marked by a strike-slip fault or a subduction zone. Passive margins specify the region around the Atlantic Ocean, Arctic Ocean, and western Indian Ocean, and define the entire shores of Africa, Greenland, India and also Australia.