Changes

===The Cause of Plate Motion===

===The Cause of Plate Motion===

====Mantle Convection====

====Mantle Convection====

The widely accepted opinion regarding the cause of the plates move at this time is because of the convection currents in the mantle. The heat from the core of the Earth is transferred to the surface of the Earth through the mantle. The heat from the core warms up the liquid rock on mantle that closest to the core, causing the liquid rock to expand and rise toward the [[crust]]. The cooler liquid rock near the surface sinks back down toward the core. In doing so, a current of liquid rock is set up flowing toward the surface and back down again. This mantle convection is believed the causes the plates movement.

The widely accepted opinion regarding the cause of the plates move at this time is because of the convection currents in the [[mantle]]. The heat from the core of the Earth is transferred to the surface of the Earth through the mantle. The heat from the core warms up the liquid rock on mantle that closest to the core, causing the liquid rock to expand and rise toward the [[crust]]. The cooler liquid rock near the surface sinks back down toward the core. In doing so, a current of liquid rock is set up flowing toward the surface and back down again. This mantle convection is believed the causes the plates movement.

[[File:Mantle_convection_cell.jpg|framed|center|Mantle Convection <ref> http://research.bpcrc.osu.edu/education/rr/plate_tectonics/mantle_convection_cell.gif </ref>]]

[[File:Mantle_convection_cell.jpg|framed|center|Mantle Convection <ref> http://research.bpcrc.osu.edu/education/rr/plate_tectonics/mantle_convection_cell.gif </ref>]]

====Slab Pull====

====Slab Pull====

The other proposal is called slab pull. Cold lithosphere sinking at a steep angle through hot mantle should pull the surface part of the plate away from the ridge crest and then down into mantle as it cools. A subduction plate sinks because it is denser than the surrounding mantle. This density contrast is partly due to the fact that sinking lithosphere is cold. The subduction plate may also increase its density while it sinks, as low-density materials such as water are lost and as plate minerals collapse into denser form during subduction. Slab pull is thought to be at least twice as important as ridge push in moving an oceanic plate away from aridge crest. Slab pull causes rapid plate motion.<ref name=Carlson />

The other proposal is called slab pull. Cold lithosphere sinking at a steep angle through hot [[mantle]] should pull the surface part of the plate away from the ridge crest and then down into mantle as it cools. A subduction plate sinks because it is denser than the surrounding mantle. This density contrast is partly due to the fact that sinking lithosphere is cold. The subduction plate may also increase its density while it sinks, as low-density materials such as water are lost and as plate minerals collapse into denser form during subduction. Slab pull is thought to be at least twice as important as ridge push in moving an oceanic plate away from aridge crest. Slab pull causes rapid plate motion.<ref name=Carlson />

===Continental Drift===

===Continental Drift===