How Does Plate Tectonics

Affect the Rock Cycle?

eBook Created By:  Amy Zbylut

Original Author:  Corina Fiore, eHow Contributor

Illustrations Provided By:  Flickr Contributors

Plate Tectonics

Plate tectonics is the movement of the Earth's crust through convection currents that occur in the mantle. Divergent plate boundaries occur where hot magma rises to the surface, pushing the plates apart. The mid-ocean ridges form at divergent plate boundaries. Convergent plate boundaries occur where cooled rock becomes denser than the rocks around it and sinks back into the mantle. Oceanic trenches , folded mountains and volcanic mountains occur at convergent plate boundaries. Sliding plate boundaries occur when one plate slides past another plate through a twisting force. The San Andreas Fault is an example of a sliding plate boundary.

Igneous Rocks and Plate Tectonics

Igneous rocks form from the cooling of magma or lava. At diverging plate boundaries, convection currents bring hot magma to the surface. This hot magma flows out onto the ocean floor, forming extrusive, finely grained igneous rocks. At convergent plate boundaries, sedimentary rock from the ocean floor gets pushed down into the mantle. The crust increases in temperature as it dives deeper into the mantle. Eventually, the crust melts and rises to the surface causing a volcanic eruption, creating igneous rocks. Sometimes, magma that gets pushed up at plate boundaries cools before it gets there. It fills in cracks and voids in the bedrock . When it cools, it creates igneous rock formations, such as dikes and batholiths .

Metamorphic Rocks and Plate Tectonics

Metamorphic rocks form when rocks change after undergoing extreme pressure or temperature increase. These temperature changes must be hot enough to reorganize matter within the rock but not hot enough to melt it. Hot magma pushes itself to the surface at both divergent plate boundaries and convergent plate boundaries. This magma comes in contact with rocks as it rises to the surface. The magma is hot, heating the rocks around it. As the rocks heat, they change and become metamorphic rocks. This process is called contact metamorphism . Regional metamorphism occurs at convergent plate boundaries, due to intense pressure. As two plates collide, the Earth's crust folds and faults. The intense pressure changes large areas of the Earth's crust into metamorphic rock. Mountain ranges are typically metamorphic rock, due to plate tectonic processes.

“Rocks Rock Harder” – Bill Nye the Science
Guy

Rocks are formed in many different ways
I want to talk about them if that’s okay
Made by pressure, heat and water we rock hard but
ROCKS ROCK HARDER
Igneous rocks form inside the ground
Made when melted rocks cool down
Lave, pummus, great big granite, rocks sitting on
this planet
Made by pressure, heat and water we rock hard but
ROCKS ROCK HARDER
Heat and pressure get their kicks, making rocks
go metamorphic
Goes down deep inside the Earth, a fine place to
have your birth
Sedimentary rocks are made from dust
Like sandstone, covered gray and rust
Wind and water break um down
Cut big canyons in the ground
Made from pressure, heat and water we rock hard but
ROCKS ROCK HARDER
But rocks rock harder

Music Video for Rocks Rock Harder:  http://www.youtube.com/watch?v=Aqy-p41VpKU