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Landforms associated with destructive margins

Oceanic Continental Plate Convergence. Oceanic crust is denser than continental crust, when plates converge the oceanic is subducted and taken down into the aesthonosphereAs oceanic crust descends, friction builds up and releases causing major earthquakes around the marginRock is scraped off the

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Landforms associated with destructive margins

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    1. Landforms associated with destructive margins Destructive margins are found where plates converge. The 3 types of convergent margin are: Oceanic plate meeting continental plate Oceanic plate meeting oceanic plate Continental plate meeting continental plate

    2. Oceanic – Continental Plate Convergence Oceanic crust is denser than continental crust, when plates converge the oceanic is subducted and taken down into the aesthonosphere As oceanic crust descends, friction builds up and releases causing major earthquakes around the margin Rock is scraped off the descending oceanic crust helping to create young fold mountains on the continental crust (e.g. the Andes) Deep ocean trenches mark where a plate begins to descend below another. Can be up more than 10km deep. Friction causing by the subduction of one plate creates great heat, causing the descending to melt. New, young magma tries to rise through cracks and fissures, where they meet the surface – volcanoes are formed.

    4. Oceanic – Oceanic Plate Convergence The crust that is subducted is usually the slightly more dense of the two, or the one that is moving the quickest. Very similar processes occur to oceanic-continental crust convergence, but the volcanoes created form islands – known as arcs (Aleutian Islands) Ocean trenches are incredibly deep (Marianas Trench in Pacific)

    5. Continental – Continental Plate Convergence Where two continental plates converge, neither will be subducted – instead they will collide with each other and a collision margin will form. Collision margins create young fold mountains with deep roots in the lithosphere. The collision of Indo-Australian plate with the Eurasian plate some 40 million years ago formed the Himalayas, home to Mt Everest (8,848m) Isostatic change is causing Mt Everest to grow by 2.5cm a year.

    7. Conservative Margins Often referred to as passive or slip margins – occur where two plates are moving parellel to each other E.g. San Andreas Fault in California, and Alpine Fault in New Zealand Areas of seismic activity, but not vulcanism

    9. Hawaiian Volcanic Chain and hot spot The main Hawaiian island is closest to the hot spot and most volcanically active Older, less active and volcanically extinct islands lie to the north west, having been moved away from the hot spot. Pacific Plate moves at 10cm/yr – new island will form to the south east of Hawaii as the Loihi submarine volcano builds up.

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