Metamorphic Rocks

Rock cycle

General Features metamorphic means “change in shape” metamorphic rocks can come from any other kind of rock (called the “parent rock”) rocks are changed (undergo metamorphosis) due to heat and pressure

Texture for Metamorphic Rocks is Alignment and Size of Crystals foliated texture = parallel alignment foliated texture = flat or wavy bands or stripes non-foliated texture = not pressed into sheets also called “massive”

Foliated Rock Classification Foliated Classified 1. Nature of foliation 2. Size of Crystals 3. Degree to which minerals segregated into light and dark bands

Rock Cycle

Types of Metamorphism Contact metamorphism High heat, low pressure Parent rock came into contact with a heat source How could the parent rock be heated up? What types of formations could provide this heat source?

Types of Metamorphism ctd. Regional Metamorphism High pressure, high heat Gneiss = "nice" Schist Parent rock changes over a widespread area Where could the rock change over a widespread (area that is as large as a state or even several countries) area?

Types of Metamorphism ctd.

Summary Questions What are heat and pressure changing? What can texture tell you about a metamorphic rock?