Metamorphic Rocks

1. Metamorphic Rocks 2006 Prentice Hall Science Explorer- Earth Science Liz LaRosa http://www.middleschoolscience.com 2009 Images from Geology.com unless otherwise noted

2. Metamorphic Rock • Metamorphic comes from the Greek word meta, meaning “change” and morphosis meaning “form”. • Heat and pressure deep beneath Earth’s surface can change any rock into metamorphic rock. • When rock change into metamorphic roc, its appearance, texture, crystal structure, and mineral content change. • Metamorphic rock can form out of igneous, sedimentary, or other metamorphic rock.

3. Metamorphic Rock • Sometimes forces inside Earth can push the rock down toward heat in the mantle. • Pockets of magma rising through the crust also provide heat that can produce metamorphic rocks. • The deeper a rock is buried, the greater the pressure many times greater than the Earth’s surface, the minerals in a rock can be changed into other minerals. http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm

4. Types of Metamorphic Rock • Geologists classify metamorphic rocks according to the arrangement of the grains that make up the rocks. • Foliated- metamorphic rocks that have their grains arranged in parallel layers of bands. Ex- slate, schist, and gneiss. • Non-foliated- metamorphic rocks that have mineral grains arranged randomly. Ex- marble, quartzite

5. Metamorphic Rock • Foliated - contain aligned grains of flat minerals in parallel layers or bands Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains. It typically contains abundant quartz or feldspar minerals.

6. Metamorphic Rock • Non-Foliated – mineral grains are not arranged in plains or bands, just random. Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone. It is composed primarily of calcium carbonate.

7. Metamorphic Rock • Determine if the following rock samples are foliated or non-foliated: Quartzite Amphibolite Phyllite Foliated

8. Types of Metamorphism Types of Metamorphism • Contact Metamorphism – heated by nearby magma • Increased temperature changes the composition of the rock, minerals are changed into new minerals. Hornfels is a fine-grained non-foliated metamorphic rock produced by contact metamorphism http://www.windows.ucar.edu/tour/link=/earth/geology/meta_contact.html&edu=h igh&fr=t

9. Types of Metamorphism • Regional Metamorphism – pressure builds up in rocks that is deep within the Earth • Large pieces of the Earth’s crust collide and the rock is deformed and chemically changed by heat and pressure http://www.windows.ucar.edu/tour/link=/earth/geology/meta_regional.html&edu=high&fr=t

10. Uses of Metamorphic rock • Marble and slate are two of the most useful metamorphic rock. • Marble is is mostly used for building and sculpture. Lincoln Memorial in Washington, D.C. is made of gleaming white marble. • Slate comes in a variety of colors, including gray, black, red, and purple. Because it is foliated, slate splits easily into flate pieces. These pieces can be used for flooring, roofing, outdoor walkways, chalkboards, and as trim for stone buildings.