Metamorphic Rocks - A rock that has been changed by extreme heat and/or pressure.

“morph” means to change (like the Mighty Morphin’ Power Rangers No melting but the texture or chemistry changed. Heat – comes from overlying rock and/or nearby magma Pressure – comes from overlying rock and/or squeezing from plate tectonics.

Types of Metamorphism 1)Contact Metamorphism – when molten rock comes in contact with solid rock Relatively thin layer of metamorphism around an igneous intrusion.

Rhyolite Mafic Intrusion Contact metamorphism

2) Hydrothermal Metamorphism “hydro” means water “thermal” means heat Associated with the mid-ocean ridge and black smokers.

3) Regional Metamorphism large area of metamorphism (ex. New England is one big area of regional metamorphism) Associated with convergent boundaries. Classified as either high, medium, or low grade.

Metamorphic Textures 1) Foliated – have layers or bands of minerals. pressure caused minerals to align in the same direction – Examples: Schist (comes from mica) Gneiss (comes from granite)

Metamorphic Textures 2) Non-Foliated – no layers. Mostly a result of heat. Examples: -Quartzite (comes from quartz or sandstone) - Marble (comes from limestone) - good for sculptures.

*Any type of rock (igneous, sedimentary, or metamorphic) can be changed into any other type of rock! - This is called the ROCK CYCLE. Rocks-01.htm Rocks-01.htm

Rock Cycle Awesome Rock Cycle Animation