Active and also 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 mid-ocean ridges. The continental margins space the shallow water areas found in proximity come continents. The continent margins space the zone of the ocean floor that separate the thin oceanic late from thick continental crust. Together, the continental shelf, continental slope, and also continental increase are called the continental margin. Continent margins constitute around 28% the the oceanic area.

An active continental margin is uncovered on the top edge of the continent where subduction occurs. Active continental margins are typically narrow from coast to shelf break, through steep descents into trenches. Fantastic example is the west coastline of southern America. Energetic margins are commonly the website of tectonic activity: earthquakes, volcanoes, hill building, and also the formation of brand-new igneous rock. These are often marked by uplift and also volcanic hill belts ~ above the continent plate, and also by island-arc chains on the oceanic plate. Less frequently there is a strike-slip fault, comparable to the one that defines the southern shore of west Africa. Most of the east Indian Ocean and also nearly every one of the Pacific ocean margin are examples of active margins. Energetic margins deserve to be convergent or change margins.

A passive margin is the shift between oceanic and continental lithosphere that is no an energetic plate margin. A passive margin forms by sedimentation above an old rift, now marked by transitional lithosphere. Continental rifting creates new ocean basins. At some point the continent rift forms a mid-oceanic ridge and the locus of extension moves far from the continent-ocean boundary. The shift between the continental and also oceanic crust the was originally produced by rifting is recognized as a passive margin. Passive spare part are uncovered at every ocean and also continent boundary that is not marked by a strike-slip fault or a subduction zone. Passive margins define the an ar around the Atlantic Ocean, Arctic Ocean, and also western Indian Ocean, and define the entire coastlines of Africa, Greenland, India and also Australia.

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Lock are likewise found on the east coast of phibìc America and also South America, in western Europe and also most of Antarctica. Eastern Asia also contains some passive margins.