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The Earth, DF: Definition. - Coggle Diagram
The Earth
Plate tectonics
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Plates
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Slide, separate, collide past eachother along boundaries.
Along boundaries volcanoes, earthquakes, fold mountains occur.
Convection currents
Magma heated in lower mantle, rises towards lithosphere, cools and becomes semi-molten, moves sideways and sinks, sideways movement causes friction, friction moves plates.
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All landmasses origanally joined together in one super continent- Pangaea. Broke apart to form our world today.
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Subduction
DF
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Where plates pull apart, new seafloor created.
Mid-Ocean ridges are underwater volcanoes which form as lava reaches the surface through separating plates.
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Slab pull
Heavier oceanic plate collides with light oceanic plate, oceanic plate sinks and melts, before melts, sinks in mantle, drags rest of plate with it.
DF
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Made up of dense, heavy metals.
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The Mantle
DF
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Made up of layers of rock, molten close to the core. Closer to crust, semi-molten.
Types
Lower Mantle
Molten magma, convection currents begin here.
Asenthosphere
Semi-molten rock, lithosphere slides on top.
Lithosphere
Solid upper mantle and crust, slides on asthenoshpere, briken sections called plates.
The Crust
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Types
Continential
Average thickness 45km, light.
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Seafloor spreading
New seafloor made at mid-ocean ridges, older seafloor pushed towards continents, oceans getting bigger.
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Mid-Ocean ridges
Chain of underwater volcanoes , plates separating ocean floor thinner here.
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