Metamorphic Rocks How do metamorphic rocks form How

Metamorphic Rocks • How do metamorphic rocks form? • How do types of metamorphic rock differ?

Metamorphic Rocks • metamorphism • nonfoliated rock • plastic deformation • contact metamorphism • foliated rock • regional metamorphism

Metamorphic Rock Formation • Metamorphism is any process that affects the structure or composition of a rock in a solid state as a result of changes in temperature, pressure, or the addition of chemical fluids. • Most metamorphic rocks form deep within Earth’s crust. • Like igneous rock, metamorphic rocks form under high temperature and pressure conditions.

Metamorphic Rock Formation (cont. ) • Plastic deformation is the permanent change in the shape of rock by bending and folding. • Plastic deformation occurs during uplift events when tectonic plates collide and form mountains.

Metamorphic Rock Formation (cont. ) • The rock that changes during metamorphism is called the parent rock. • The temperatures required to metamorphose rock depend on the parent rock’s composition.

Both temperature and pressure increase with depth in Earth’s crust and mantle.

Metamorphic Rock Formation (cont. ) Under what conditions do metamorphic rocks form?

Metamorphic rocks are classified into two groups based on texture: foliated rocks and nonfoliated rocks.

Metamorphic Rock Identification • Foliated rocks contain parallel layers of flat and elongated minerals. • Metamorphic rocks that have mineral grains with a random, interlocking texture are nonfoliated rocks.

Metamorphic Rock Identification (cont. ) foliate from Latin foliatus, means “consisting of thin, leaf-like layers”

Metamorphic Rock Identification (cont. ) • During contact metamorphism, magma comes in contact with existing rock, and its thermal energy and gases interact with the surrounding rock and forms nonfoliated metamorphic rock. • Regional metamorphism is the formation of metamorphic rock bodies that are hundreds of square kilometers in size.

Metamorphic Rock Identification (cont. ) Compare and contrast contact metamorphism and regional metamorphism.

• Foliated metamorphic rocks have distinct layers of flat and elongated minerals. • A nonfoliated metamorphic rock has minerals arranged in a random, interlocking texture. • Contact metamorphism occurs when rocks come in contact with magma without melting.

When rocks bend or fold without melting, the permanent change in the rock’s shape is called what? A. metamorphism B. foliation C. plastic deformation D. rock deformation

What kind of rocks contain parallel layers of flat and elongated minerals? A. foliated rocks B. metamorphic rocks C. crystallized rocks D. nonfoliated rocks

Which type of metamorphism occurs when magma comes in contact with existing rock, and its thermal energy and gases interact with the surrounding rock? A. regional C. plastic B. crystal D. contact

Do you agree or disagree? 7. With the right pressure and temperature conditions, minerals in a rock can change shape without breaking or melting. 8. Metamorphic rocks have layers that form as minerals melt and then recrystallize.

Key Concept Summary Interactive Concept Map Chapter Review Standardized Test Practice

• Igneous rocks form from molten rock that cools and crystallizes. • Sedimentary rocks form from compaction and cementation of sediments or evaporation and crystallization of minerals dissolved in water. • Metamorphic rocks form from exposure of existing rocks to high pressures, temperatures, or the addition of chemical fluids.

Lesson 1: Rocks and the Rock Cycle • There are three major rock types—igneous, sedimentary, and metamorphic. Geologists study rock texture and mineral composition to identify rocks of each type. Nancy Simmerman/Getty Images • Rocks can melt or recrystallize. Rocks exposed on Earth’s surface can break down due to forces such as water, ice, wind, and gravity. New rocks form under changing temperature and pressure conditions or the addition of chemical fluids.

Lesson 2: Igneous Rocks • Igneous rocks form when volcanic material cools and crystallizes. • Crystal size is dependent on how quickly the magma or lava cools. • Igneous rocks range in color from light to dark, depending on their mineral composition.

Lesson 3: Sedimentary Rocks • Weathering, erosion, transportation, deposition, compaction, cementation, and crystallization are the important processes in the formation of sedimentary rocks. • A sedimentary rock’s texture and mineral composition depends on where it formed and the forces that created it. National Geographic/Getty Images

Lesson 4: Metamorphic Rocks • Metamorphic rocks form from a parent rock that has been exposed to increases in temperature, pressure, or the addition of chemical fluids. • Some metamorphic rocks have foliated textures and are deformed. Others are composed of coarse and blocky crystals that are uniform in color.

Which term refers to the series of processes that change one type of rock into another type of rock? A. metamorphoses B. sediment deposit C. rock cycle D. rock deposit

Geologists can determine if an igneous rock is extrusive or intrusive by studying its composition and which of these? A. size C. weight B. color D. texture

Which type of rock is sedimentary rock that was formed by organisms or contains the remains of organisms? A. chemical C. carbonate B. biochemical D. clastic

Which process occurs when minerals dissolved in water crystallize between sediment grains? A. cementation B. compaction C. crystallization D. erosion

Which type of rocks contain parallel layers of flat and elongated minerals? A. igneous B. foliated C. nonfoliated D. sedimentary

Which term refers to magma that erupts on Earth’s surface? A. sediment B. metamorphic rock C. lava D. crystals

When magma or lava cools and crystallizes, it creates which type of rock? A. igneous B. sedimentary C. metamorphic D. mineral

An igneous rock is classified as extrusive if which part is difficult or impossible to see without a magnifying glass? A. minerals B. crystals C. holes D. grains

Which term refers to any process that affects the structure or composition of solid rock? A. chemical reaction B. plastic deformation C. foliation D. metamorphism

Which process refers to the formation of metamorphic rock bodies that are hundreds of square kilometers in size? A. cementation B. regional metamorphism C. contact metamorphism D. plastic deformation