Rock Cycles

Even rocks have a cycle. Rocks are continually circulating in the mantle just below the crust of the earth. They are sometimes thrust up into the crust due to convection currents. Imagine really thick jam slowly cooking in a big pot on a stove. The jam is thick, and when it reaches a high temperature, convection currents circulate through it. Occasionally big bubbles of steam erupt from the jam and splash onto the top of the stove. This is how rocks get thrust up onto the top of the crust from the boiling mantle below. Rocks can also reach the surface when they are spit out by volcanoes.

Once on the surface of the earth, rocks cool down. Over time, they are broken up or worn down by weather, and the fragments are carried back to the ocean by way of wind, rain, and the flow of rivers and streams. All of these small pieces of rock collect as sediment at the bottom of seas and oceans. The sediment slowly solidifies into rock and is sometimes drawn back down in to the mantle at subduction zones or reaches the surface again as sea levels change or plates collide.

Sample some of the following activities to learn more about rocks and their cycles.


Places To Go    People To See    Things To Do    Teacher Resources    Bibliography

Places To Go

The following are places to go (some real and some virtual) to find out about rocks and their cycles.

Ayers Rock
Visit famous Ayers Rock in Australia. It is a sacred place to the aboriginal people, and it is made of limestone which is a sedimentary rock.
Devils Tower National Monument
Visit Devil's Tower in Wyoming. The tower is a big hunk of igneous rock. It was formed by magma solidifying in a vertical tube that was once the heart of a volcano.
Easter Island
Stroll along the beaches of Easter Island. Those big, mysterious statues are made of volcanic tuff which is an igneous rock.
The Geology of the Grand Canyon
Erosion is part of the cycle of how rocks erode from wind, water, glaciers, and shifts in temperature. Travel to the Grand Canyon to view one of the most magnificent examples of how a river had carved its way through sedimentary rock.
The Giant's Causeway
Travel to the Giant’s Causeway in Antrim, Northern Ireland to study some unusual igneous rocks. These unique rock structures were formed when basalt lava cooled and then shrank to form hexagon-shaped columns. The legend is that an Irishman named Finn McCool built the causeway so that he could walk across to Scotland and fight a giant.
Grand Canyon Explorer
Virtually visit the Grand Canyon. The layer's of the earth's crust are plainly visible there.
Great Pyramid of Khufu
Visit the Great Pyramid in Egypt. It's made from limestone which is a sedimentary rock.
Great Sphinx
Visit the Great Sphinx in Egypt. It's made from limestone which is a sedimentary rock.
Visit the hoodoos of southern Utah. These unusual rock formations are columns of soft sandstone that are topped by harder rock caps. The hard tops of the hoodoos have protected the rock beneath from being eroded by rain.
How Do Soils Form?
Visit your backyard and learn all about soil. Soil consists of tiny rocks, minerals, dead plants and animals, microbes, gases, and water. As plants and animals die, microbes break them down to eventually become soil.
Mount Rushmore
Visit Mount Rushmore. It's made from granite which is igneous rock.
Rock & Roll Hall of Fame and Museum
Visit the Rock and Roll Hall of Fame.
Shiprock Pinnacle
Visit Shiprock Pinnacle in New Mexico to view a huge outcropping of igneous rock. This enormous rock was once a plug-like mass of magma that filled the chimney vent of a volcano. It exploded from the volcano thousands of years ago and now fills the horizon in this remote area of New Mexico.
Taj Mahal
Visit the Taj Mahal. It is one of the world’s largest and most famous marble buildings. Marble is a metamorphic rock and is formed when heat and pressure change the structure of igneous or sedimentary rock.
Washington Monument
Climb to the top of the Washington Monument. The exterior is made of white marble which is a metamorphic rock. Marble is formed when limestone is put under extreme pressure and heat. The interior of the monument is granite which is an igneous rock.
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People To See

Ask a Geologist
Geologists are rock experts. Ask them anything.
Chalk is a sedimentary rock and is formed from the shells and skeletons of microscopic sea creatures. The White Cliffs of Dover are made up of countless numbers shells of sea creatures that fell to the bottom of the sea and then became compacted over the centuries.
See a gemologist and learn about the characteristics of gems. What is the difference between a rock and a mineral and a crystal and a gem? Minerals are natural chemicals. Rocks are composed of innumerable grains of minerals. Of the 3,000 minerals in the world, only about 130 of them form gems.
Igneous Rock Formation
Magma, which is melted rock inside the earth, oozes and flows and moves around beneath the surface of the earth. When it pushes up through the crust of the earth or erupts from a volcano, it is no longer called magma; it is called lava. Cooled lava becomes igneous rock.
James Hutton
Meet James Hutton. He was from Scotland. He is considered to be the father of modern geology.
Kīlauea -- Perhaps the World's Most Active Volcano
Spend some time with the people on the island of Hawaii. Kilauea Volcano is one of the earth's most active volcanoes. It has been constantly spilling out lava since 1983.
Mechanical Weathering
Spend time with geologists who study rocks. Weathering is part of the rock cycle. Rocks break down into smaller pieces from the effects of water freezing in small holes of rocks, from the effect of waves, from the flow of water in rivers and streams, and from wind.
Metamorphic Rocks
Metamorphic rock is rock that has changed its form due to intense heat or pressure. Michelangelo carved his famous sculpture of David from a large hunk of Carrara marble.
Mohs Scale of Mineral Hardness
Make the acquaintance of Mr. Mohs. In 1812, he developed a scale of hardness for minerals.
Mount Rushmore National Memorial
See George Washington, Thomas Jefferson, Teddy Roosevelt, and Abraham Lincoln. Their faces are carved from igneous rock at Mount Rushmore.
Silicon is used is used in circuit boards and chips for the computer industry. Meet scientists who manufacture silicon. Silicon is a crystal, but is does not occur in a pure form in nature. It can now be made artificially.
William Steig
Get to know Sylvester the donkey. By a set of strange circumstances, he turned into a rock. (It may have been an igneous rock). Read all about his adventures in William Steig's Sylvester and the Magic Pebble which won a Caldecott Medal in 1970.

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Things To Do

Birthstones By Month
Learn about which gemstones are associated with different months of the year. They are called birthstones.
Learn more about Utah's official rock.
Desert Environment & Geology: Rocks, Gems & Minerals
Learn about the rocks and minerals that are in the Great Basin Desert which is in part of Utah. Utah has a lot of topaz.
Mineral Identification
All the different rocks in the world are made up of minerals. Some rocks contain just one kind of mineral, and other rocks contain many kinds of minerals. It all depends on how the rock was formed.
The Rock Cycle
Think about the differences between a rock and a mineral. Then view photos of minerals at The Mineral Gallery and The Mineral and Gemstone Kingdom and photos of rocks at Igneous Rocks.
The Rock Cycle
Check out this diagram of the rock cycle to understand how rocks form.
Sedimentary Rock
Sediment is turned into sedimentary rock by two processes. Learn more about these processes.
Types of Rocks
To learn more about the rock cycle, start your own collection of rocks. They are certainly easy to find.
What's the Hardness of Your Mineral
Testing the hardness of a mineral can help you identify what it is. Learn more about the hardness of minerals and about the Mohs scale where talc is rated as a 1 and diamond is a 10.
Utah State Library
Check out Utah's official state rock.
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Teacher Resources

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  • Burton, Jane. The Nature and Science of Rocks. Milwaukee, WI: Gareth Stevens Pub., 1998.
  • Challoner, Jack. Rocks and Minerals. Milwaukee, WI: Gareth Stevens, 1999.
  • Curtis, Neil.. Rocks and Minerals. New York: Oxford University Press, 1998.
  • Kittinger, Jo S. A Look at Rocks: From Coal to Kimberlite. New York : Franklin Watts, c1997.
  • Morris, Neil. Rocks and Minerals. New York, N.Y.: Crabtree Pub. Co., c1998.
  • Snedden, Robert. Rocks and Soils. Austin, Tex.: Raintree Steck-Vaughn, 1998.
  • Staedter, Tracy. Rocks and Minerals. Pleasantville, N.Y.: Reader's Digest Children's Books, c1999.