Metamorphic rocks are formed by heat and pressure acting on older igneous, sedimentary, or other metamorphic rocks. Earthquakes and volcanic activity apply this heat and pressure, which can melt rock into magma or flatten and rearrange mineral grains without melting. Metamorphic rocks are classified based on their texture as either foliated, with flattened and aligned mineral grains, or nonfoliated, with rearranged but not layered grains. Common metamorphic rocks include slate, gneiss, marble, and quartzite formed from their igneous or sedimentary protoliths under metamorphism.

1. Metamorphic Rocks FORMED BY HEAT AND PRESSURE

2. OLDER ROCKS MAY BE FORMED INTO A NEW TYPE OF METAMORPHIC ROCK

3. - Metamorphic rocks can form from igneous, sedimentary or other metamorphic rocks.

4. EARTHQUAKES AND VOLCANIC ACTIVITY CAUSE HEAT AND PRESSURE TO ACT ON ROCKS.

5. - sometimes temperature and pressure are great enough to melt rock, forming magma.

6. - sometimes pressure flattens mineral grains in rocks without melting them.

7. - as pressure and temperature continue to increase over time, one type of rock can change into several different metamorphic rocks.

8. METAMORPHIC ROCKS ARE CLASSIFIED BY CLASSIFICATION AND TEXTURE

9. CLASSIFICATION: 1. Foliated texture: mineral grains flatten and line up in parallel layers or bands.

10. 2. Nonfoliated texture: mineral grains grow and rearrange but do not form layers.

11. Foliated Rocks Original Rock: shale (sedimentary) Metamorphic Rock: slate

12. Foliated Rock Original Rock: granite (igneous) Metamorphic Rock: gneiss

13. Nonfoliated Rock Original Rock: limestone (sedimentary) Metamorphic Rock: marble

14. Nonfoliated Rock Original Rock: sandstone (sedimentary) Metamorphic Rock: quartzite (melted sand)

15. USES OF METAMORPHIC ROCK: 1. blackboards, roofs, sidewalks, floors: slate

16. 2. building stone: gneiss, marble, quartzite

17. 3. statues, tombstones: marble AND GRANITE