Restless earth notes

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PLATE NAMES-

-Pacific

-Eurasian

-indo australian

-African

-Antarctic

-South American

-Nazca

Why do the plates move?

-the plates move because the semi liquid mantle has convection currents. these currents move the crusts around the world. millions of years ago all the plates were attached and formed a summer continent but convection currents moved them apart.

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The Restless Earth

At a constructive plate boundary, two plates move apart. As the two plates move apart, magma rises up to fill the gap. This causes volcanoes. However, since the magma can escape easily at the surface the volcano does not erupt with much force.

Earthquakes are also found at constructive boundaries.

An example of a constructive boundary is the Mid-Atlantic Ridge.

-Destructive Plate margins

A destructive plate boundary is found where a continental plate meets an oceanic plate.

The oceanic plate descends under the continental plate because it is denser. As the plate descends it starts to melt due to the friction caused by the movement between the plates. This melted plate is now hot, liquid rock (magma). The magma rises through the gaps in the continental plate. If it reaches the surface, the liquid rock forms a volcano.

SUPER VOLCANO

super volcanos are found at hotspots within the plates. these hotspots are caused by huge magma chambers found near the earths crusts. a super volcano is up to 100x more powerful than an normal volcano. its eruption in result could kill and annihilate the human race.

One super volcano is the yellowstone caldera in the USA. the depression in the land there is called a caldera and is the cause of the hotspot.

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fold mountains occur at collision plate margins such as into australian and eurasian plates. they move towards each other and collide. inbeteen these plates theres a depression called a geosyncline filled with sea water. over time rivers loads will deport here and the well will be filled with sediment. the heat and pressure caused by the two plates pushing towards each other combined with the sediment cause sedimentary rock to be formed in the middle. then soon this rock will begin to fold into anticlines and synclines. as the plates are still moving the fold mountains will continue to grow. an example of this is the himalayas.