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Metamorphic Rock. Metamorphic Rock. What does the term metamorphose mean? What are examples in which things change?. Metamorphic Rock. Metamorphic rocks: form when pre-existing rocks are exposed to increases in temperature and pressure .
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Metamorphic Rock • What does the term metamorphose mean? • What are examples in which things change?
Metamorphic Rock • Metamorphic rocks: form when pre-existing rocks are exposed to increases in temperature and pressure. • Where is the heat source responsible for the high temperatures that morph rocks? • Derived from earth’s internal crust
Metamorphic Textures • Metamorphic rocks are classified into 2 textural groups • Foliated • Nonfoliated • Textures and mineral compositions are used to identify metamorphic rocks
Metamorphic Textures • Foliated: Layers and bands of minerals • Foliation happens when pressure is applied from opposite directions. Foliation develops perpendicular to the pressure
Metamorphic Textures • Nonfoliated: minerals form blocky crystal shapes • Example: Quartzite and Marble
Grades of Metamorphism • Different combinations of temperature and pressure result in different grades of metamorphism. • Low Grade- Low Temperature and Pressure • High Grade- High Temperature and Pressure
Types of Metamorphism • Regional Metamorphism: When high temperatures and pressures affect large regions of Earth’s crust • Contact Metamorphism: When molten material , such as intrusive igneous intrusions, comes in contact with solid rock • Hydrothermal Metamorphism: When very hot water reacts with rock and alters its chemical and internal composition.
Rock Observations • Look at the various rocks • In your notebook you need to write a description of each rock (10) • Particle size, color, texture • Determine if it is foliated or non-foliated
Metamorphic Chocolate Demo • You will have 3 pictures – one after each stress is applied • What are the stresses that are applied? • How does your third picture change from you first?