Rocks Rock!

The Rock Cycle

3 Types of Rocks  Sedimentary  Igneous  Metamorphic

Sedimentary Rock  This type of rock forms when small pieces of clay, silt, or sand (and plants and animals) settle into layers on the bottoms of lakes and oceans.  Over time, the layers harden into the sedimentary rock we see today.  Most fossils are found in sedimentary rock.

Examples of Sedimentary Rock  Sandstone  Limestone  Shale

Igneous Rock  Melted rock (magma) can push up through cracks in the earth’s crust.  When the melted rock cools and hardens, it is called igneous rock.  There are two classifications of igneous rock: extrusive and intrusive.

Examples of Igneous Rock  Basalt  Granite  Obsidian

Metamorphic Rock  The word ‘metamorphic’ comes from a word that means “to change”.  These are rocks that were changed from one kind to another kind by heat and pressure.  Heat + Pressure + Time = Metamorphic Rock

Examples of Metamorphic Rocks  Marble – (from limestone)  Gneiss – (from granite)  Quartzite – (from sandstone)

Famous Examples Igneous: Basalt Devil’s Tower Wyoming Sedimentary: Limestone Metamorphic: Marble The Taj Mahal Agra, India The Great Sphinx Egypt All photos licensed under the ‘Creative Commons’. Sam and Ian Francisco Martins Michael Schroeter

Sources  Discovery Education. "Sedimentary Rock." Discovery Education:  Discovery Education. "Metamorphic Rock." Discovery Education:  Discovery Education. "Igneous Rock." Discovery Education:   Cole, Joanna. (1987). The Magic School Bus Inside the Earth. Scholastic, New York, New York.  