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Unformatted text preview: Geology 1001
Chapter 6 Metamorphic Rocks Quiz Results!!!
Average Grade: 8.1/10 1 Metamorphic Rocks: altered pre-existing rocks pre- Altered by heat and/or pressure Metamorphic Rocks Parent Rock: rock prior to metamorphism. Rock:
Ig. Ig. Sed. Meta. + Increased T/P = Metamorphic Rock Metamorphic Rocks Meta: Change Meta: Morph: Form Morph: What Changes? Minerology Texture Composition 2 Metamorphic Rocks Changes occur in the solid state! Metamorphic Rocks: Fig 6.2, p. 133 Metamorphic Rocks Pressure increases with depth at about the same rate everywhere. Increases 300-400 bars per Kilometer 300- 3 Temperature Temperature increases are variable. Temperature Temperature increases are variable. 50 Km 30 Km 150 Km Role of Temperature Igneous rocks: affects chemical composition, texture, and minerology as rocks solidify Sedimentary Rocks: involved in the transformation from sediments to rocks. Metamorphic Rocks: affects chemical composition, texture, and minerology in the solid state 4 Role of Pressure Igneous rocks: affects the melting temperature of minerals Sedimentary Rocks: involved in the transformation from sediments to rocks. Metamorphic Rocks: affects chemical composition, texture, and minerology in the solid state. Pressure = Stress Directed Stress: In a particular direction. Stress: Types of metamorphism Regional Metamorphism: Rocks are subjected to high pressures and temperatures over a large region. region. Associated with convergent plate boundaries. 5 Regional Metamorphism Continent-Continent Convergence Continent- Regional Metamorphism Ocean-Continent Convergence Ocean- Pressure = Stress Confining Stress: Equal in all directions Stress: 6 Types of metamorphism Contact Metamorphism: Rocks are subjected to localized heat. Associated with magma chambers. Contact Metamorphism Contact Metamorphism 7 Contact Metamorphism Contact Metamorphism Fluid Metamorphism Also called Metasomatism: reactions between Metasomatism: fluids and rock. Fluids can remove or replace minerals 8 Fluids invade and deposit minerals Convergent Boundaries Step 2: Fluids are released as the temperature increases. Divergent Boundaries Crust Mantle 9 Seafloor Metamorphism Alter the composition of basalts "Other" Metamorphism Other" Burial Metamorphism: Older sediments are Metamorphism: progressively buried by more recent sediments Associated with diagenesis of sediments (Low Grade) Burial Metamorphism Begins at the upper limit of diagenesis 10 ...
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- Spring '07