Active and Passive continent Margins
The continental margins are one of the three significant zones that the ocean floor, the various other two gift deep-ocean basins and also mid-ocean ridges. The continental margins space the shallow water areas found in proximity come continents. The continental margins are the zone the the s floor that different the thin oceanic crust from special continental crust. Together, the continental shelf, continental slope, and continental increase are dubbed the continental margin. Continent margins constitute around 28% the the oceanic area.
An active continental margin is discovered on the leading edge of the continent where subduction occurs. Active continental margins are commonly narrow from coastline to shelf break, through steep descents into trenches. Fantastic example is the west shore of southern America. Active margins are frequently the website of tectonic activity: earthquakes, volcanoes, hill building, and also the development of brand-new igneous rock. These are often marked by uplift and volcanic hill belts ~ above the continental plate, and by island-arc chain on the oceanic plate. Less frequently there is a strike-slip fault, comparable to the one that specifies the southern coast of west Africa. Many of the east Indian Ocean and also nearly every one of the Pacific s margin are instances of active margins. Active margins have the right to be convergent or transform margins.
A passive margin is the shift between oceanic and also continental lithosphere that is no an energetic plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting creates brand-new ocean basins. Eventually the continental rift creates a mid-oceanic ridge and also the locus of extension moves far from the continent-ocean boundary. The shift between the continental and oceanic crust that was originally developed by rifting is recognized as a passive margin. Passive margins are discovered at every ocean and continent boundary that is not significant by a strike-slip fault or a subduction zone. Passive margins define the region around the Atlantic Ocean, Arctic Ocean, and also western Indian Ocean, and also define the entire shores of Africa, Greenland, India and Australia.