Plate Tectonics Vocabulary Terms Emily Leonard 2/2/12Core1

Inner Core  A ball of hot, solid metals  It is solid.  It is about 2400 km in diameter.  Intense pressure makes it solid.

Outer Core  A layer of liquid metals that surround the inner core.  The pressure is lower than the inner core.  The metal is liquid.  It is about 2300 km thick.

Mantle  Hot rock that is less dense than the metallic core.  It is Earth’s thickest layer.  It measures nearly 2900 kilometers.  It is not solid.

Crust  The thin layer of rock above Earth’s mantle  It is the layer we walk on  It is the thinnest layer  It is solid

Lithosphere  The layer in Earth made up of the crust and the rigid rock of the upper mantle  It is the crust  The very upper part of the mantle is solid rock  It does not include the sky

Asthenosphere  The layer in Earth’s upper mantle directly under the lithosphere  It lies below the lithosphere  It has a relatively low density  Seismic waves pass slowly through this layer

Tectonic Plate  One of the large, moving pieces into which Earth’s lithosphere is broken and which commonly carry both oceanic and continental crust  There are 10 different plates  They are part of the lithosphere  They are on top of the athenosphere

Continental Drift  The hypothesis that Earth’s continents move on Earths’ surface  It was first put out by Abraham Ortelius  It was first introduced in 1596  Plate tectonics helped the theory of the continental drift.

Pangaea  A hypothetical supercontinent that once included all of the landmasses on Earth  The name comes from Ancient Greek  They say it formed 300 million years ago  They say it began to break up about 200 million years ago

Convection Current  A circulation pattern in which material is heated and rises in one area, then cools and sinks in another area  Convection is caused by them.  They circle throughout Earth’s layers  They are very important

Divergent Boundary  A boundary along which two tectonic plates move apart  It is related to plate tectonics  It is part of the process of two plates moving apart  It occurs in the lithosphere

Convergent Boundary  A boundary along which two tectonic plates push together In plate tectonics, a convergent boundary, also known as a destructive plate boundary (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of lithosphere move toward one another and collide. As a result of pressure, friction, and plate material melting in the mantle, earthquakes and volcanoes are common near convergent boundariesplate tectonicssubductionlithosphere mantlevolcanoes

Transform Boundary  A boundary along which two tectonic plates scrape past each other A transform fault or transform boundary, also known as conservative plate boundary since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly horizontal in either sinistral or dextral directionlithospherefaultmotionhorizontalsinistraldextral

Magnetic Reversal  A switch in the direction of Earth’s magnetic field so that the magnetic north pole becomes the magnetic south pole A geomagnetic reversal is a change in the Earth's magnetic field such that the positions of magnetic north and magnetic south are interchanged.Earth's magnetic field

Hot Spot  An area where a column of hot material rises from deep within a planet’s mantle

Subduction  The process by which an oceanic tectonic plate sinks under another plate In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zonesgeologyconvergent boundariestectonic plateEarth's mantle