The Rock CycleThe Rock Cycle

An Interactive Presentation by:An Interactive Presentation by:

Andrew DeWittAndrew DeWitt

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The Rock Cycle Home PageThe Rock Cycle Home Page

• Overview of Rock Cycle

• Igneous Rocks

• Sedimentary Rocks

• Metamorphic Rocks

• About the Author

• Resources

• Concept Map

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Overview of the Rock CycleOverview of the Rock CycleThe rock cycle describes Earth’s

natural process of recycling rocks and sediments. All the rocks on Earth fall into the three distinct categories of sedimentary, igneous, or metamorphic rocks. The names of these rock types refer to the way the rocks were formed. This interactive powerpoint will guide you through each of these three categories.

Click here to view a rock cycle video

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Igneous RocksIgneous RocksIgneous rocks are formed from

magma, the molten form of Earth’s mantle layer. These rocks can form above ground when lava comes out of a volcano, or they may form under the Earth’s surface when magma cools. When igneous rocks are broken down chemically and physically the pieces of this rock may be lithified creating sedimentary rock. Or, if these rocks undergo heat and pressure they may turn into metamorphic rock.

Granite is a common igneous rock that is formed under the Earth’s surface. About 75% of the Earth’s crust is granite.

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Sedimentary RocksSedimentary RocksSedimentary rocks form from

weathered pieces of other rocks (metamorphic, igneous, or other sedimentary rocks) or from weathered shells of sea creatures. Also, sedimentary rocks can be precipitated directly out of water as is the case with limestone. Coal is also an example of a sedimentary rock. Coal forms when dead organic matter is squeezed together before the material can be decayed. Whatever the case, these rocks must be squeezed and cemented together.

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Metamorphic RocksMetamorphic RocksMetamorphic rocks form under intense

heat and pressure. These rocks may start out as igneous, sedimentary or another type of metamorphic rock, but due to heat and pressure the characteristics change, generating a metamorphic rock. It is important to know that rocks continue to change form. What was once a sedimentary rock may become a metamorphic rock when subjected to extreme heat and pressure. With sufficient time and weathering, that metamorphic rock can become a sedimentary rock once again.

Evidence of deformation and stress is often associated with metamorphic rocks due to the fact that they were subject to extreme heat and pressure.

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About the authorAbout the authorMy name is Andrew DeWitt and I am

an Earth Science major, Biology minor at GVSU. I graduated from Hudsonville High School in 2005. I was a three sport athlete at HHS for all four years I attended there. Currently, I am preparing to enroll into the College of Education at GVSU. After a semester of teacher assisting and a semester of student teaching I will be out on the hunt for a teaching job. I enjoy all the sciences but specifically Earth Science and Geology.

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Click here for author’s contact info

About the author continued…About the author continued…

Author atop of Mauna Kea in Hawaii in summer of 2008. Elevation = 13,000 feet

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Click here to contact me via E-mail

I greatly appreciate and enjoy the outdoors. I enjoy hunting, fishing, hiking, and rock and mineral collecting. I also am also very interested in sports, particularly football, basketball, and track. I am currently a volunteer track coach at Hudsonville High School and I hope that one day I can coach at the school I teach.

ResourcesResources• Photos from the following sites:

http://evolution.itgo.com/rock_cycle/cycle.htmlwww.rocksandminerals4u.com/rock_cycle.htmlwww.geol.umd.edu/.../GEOL388/lectures/02.htmlgeology.com/rocks/igneous-rocks.shtml

• Video from United Streaming:http://streaming.discoveryeducation.com/index.cfm

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Overview of the Rock CycleOverview of the Rock CycleVideoVideo

Click on image above to view introductory video

Click here to return to overview of rock cycle

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Examples of Igneous RocksExamples of Igneous RocksRocks formed as lava cooling on Earth’s surface:

Basalt

Obsidian

Rocks formed as magma cooling under the Earth’s surface:

Rhyolite

Diorite Gabbro

Granite

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Examples of Sedimentary RocksExamples of Sedimentary Rocks

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Examples of Metamorphic RocksExamples of Metamorphic RocksIncreasing metamorphic grade (more heat and pressure) from lower left to upper right.

Slate

Phyllite

Schist Gneiss

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Concept MapConcept Map

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