Chapter 5: RocksChapter 5: RocksSection 5: Metamorphic Rocks

Metamorphic RockMetamorphic Rockfrom Greek: meta = “change”, morphosis = “form”

heat and pressure deep beneath Earth’s surface can change any rock into metamorphic rock

How Rocks ChangeHow Rocks ChangeCan change appearance, texture,

crystal structure, and mineral contentCollisions between plates can push

rock down toward mantle or pockets of magma can rise

High temperatures change size and shape of grain and extreme pressure squeezes rock so tightly that the mineral grains may line up in flat, parallel layers

Checkpoint 1Checkpoint 1What are two ways that rocks

can be exposed to intense heat sufficient to turn them into metamorphic rocks?

Checkpoint 1Checkpoint 1What are two ways that rocks

can be exposed to intense heat sufficient to turn them into metamorphic rocks?

They can be pushed down toward the mantle through plate tectonics or pockets of magma can rise.

Types of Metamorphic Types of Metamorphic RocksRocksClassified according to

arrangement of grains that make up the rocks

Types:◦Foliated◦Nonfoliated

Checkpoint 2Checkpoint 2How are metamorphic rocks

classified?

Checkpoint 2Checkpoint 2How are metamorphic rocks

classified?According to arrangement of

grains

Foliated RocksFoliated RocksHave their grains arranged in

parallel layers or bandsFolio is Latin for “leaf”May split apart along bandsE.g. slate (from shale), gneiss

(from granite)

Nonfoliated RocksNonfoliated RocksMineral grains are arranged

randomlyDon’t split into layersE.g. quartzite (from sandstone)

Nonfoliated vs. Foliated Nonfoliated vs. Foliated RocksRocks

Checkpoint 3Checkpoint 3What is the difference between

foliated and nonfoliated rocks?

Checkpoint 3Checkpoint 3What is the difference between

foliated and nonfoliated rocks?Foliated rocks are arranged in

layers.

Uses of Metamorphic RockUses of Metamorphic RockCertain metamorphic rocks are

important materials for building and sculpture◦Marble (from limestone)

Fine, even grain – can be cut into thin slabs or carved into many shapes

Easy to polish – buildings and statues◦Slate

Variety of colors Splits easily into flat pieces – flooring,

roofing, outdoor walkways, chalkboards

Checkpoint 4Checkpoint 4Why are metamorphic rocks

useful?

Checkpoint 4Checkpoint 4Why are metamorphic rocks

useful?Marble: fine, even grain; can be

cut into thin slabs or carved; easy to polish

Slate: splits evenly into flat pieces

Post-lesson QuizPost-lesson Quiz

1. How are metamorphic rocks classified?

a. by the arrangement of their grain

b. by the color of their grainc. by the size of their graind. by the texture of their grain

Post-lesson QuizPost-lesson Quiz

2. What can change about a rock when it becomes metamorphic?

a. textureb. crystal structurec. mineral contentd. all of the above

Post-lesson QuizPost-lesson Quiz

3. What two things do metamorphic rocks need to form?

a. electricity and airb. heat and pressurec. heat and waterd. pressure and water

Post-lesson QuizPost-lesson Quiz

4. What is the heat source for transforming metamorphic rocks?

a. lavab. the Sunc. magmad. thermal vents

Post-lesson QuizPost-lesson Quiz

5. Which of the following is not a metamorphic rock?

a. slateb. limestonec. marble d. gneiss