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The outer most layer of the Earth. It is high in magnesium, calcium, iron and silicon. It can be from 5 - 7 km. thick on the ocean floor and from 30 - 100 km thick on the continents. |
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The middle layer of the earth. It is nearly 3000 km thick and has three layers to it. There is the solid outer mantle, the asthenosphere where it is so hot and has so much pressure that the material is like a viscous (thick) liquid, and the dense inner layer of lower mantle. |
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| The middle layer of the mantle. It is very hot and has so much pressure on it that it behaves like a viscous fluid (very thick, hard to pour) |
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| the centre of the earth's internal (inside) structure. It has a radius of about 3500 km and is nearly spherical (round like a ball). It has two layers, the outer core and the inner core. |
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| the outer layer of the core of the planet. It is made of liquid iron and nickel |
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| The very inside of Earth. It is a very dense solid iron |
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| a large mechanical wave or vibration through the Earth. Is usually caused by an Earthquake. It is these waves that cause all the destruction. |
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| one of 12 large and 20 smaller sections of the Earth's lithosphere that drift (move around without direction) on the denser asthenosphere. |
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Continental Drift Theory [image] |
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| A theory that explains how the continents have moved around since the Earth was formed. It suggests that at the beginning all of the continents fit togethere like a jigsaw puzzle. |
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| the long periods of time, in the past, when glaciers covered most of the continents |
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| undersea mountain ranges bracketing a divergent boundary. Meaning an undersea mountain range that surrounds a boundary of plates that is pulling apart. |
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Sea-Floor Spreading [image] |
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| the widening of the sea floor at the mid-ocean ridges. It creates a new sea floor and is pushed toward and opposing (opposite) convergent (coming together) boundary where it is recycled into the mantle |
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| Extensive (very large) elongated (long and narrow) depressions where two tectonic plates converge. (come together) |
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Theory of Plate Tectonics [image] |
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| the idea that the lithosphere is divided into large tectonic plates that drift over the asthenosphere, so that some plates are splitting apart, others are coming together, and some are passing each other in opposite directions |
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Divergent Boundaries [image] |
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| the place where two tectonic plates are moving away from each other |
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| A divergent boundary that goes across land, where small volcanoes and shallow earthquakes occur (happen) |
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Convergent Boundary [image] |
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| Tectonic plates that are moving together on a collision course. Where they meet is the convergent boundary |
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| the area where tectonic plates overlap and one is pushed down beneath the other |
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Oceanic-Oceanic convergent Boundaries [image] |
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| a convergent boundary where the oceanic portion of two tectonic plates meet. May form an island |
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Oceanic-Continental Convergent Boundary [image] |
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| a convergent boundary where oceanic and continental portions of two tectonic plates meet. They create deep ocean trenches and parallel mountain chains. |
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Continental-Continental Convergent Boundary [image] |
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| A convergent boundary where the continental portions (parts) of two tectonic plates meet. This creates inland mountain ranges |
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Transform Boundary [image][image] |
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| a place where tectonic plates move past each other in opposite directions |
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Strike-Slip Faults [image][image] |
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| a type of transform boundary at which the land on either side of a fault line is moving in opposite directions parallel to the fault |
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