Metamorphism and Metamorphic Rocks Metamorphic rocks by fbw14149

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 1   Metamorphism and Metamorphic Rocks
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3    Metamorphic rocks
      Exposed metamorphic rocks make up large parts of continents
       (shields)
4    I. Agents of Metamorphism
      (1) Heat
         increases the rate of chemical reactions
      A. Heat sources
         intrusive magma
         deep burial along subduction zones
         Geothermal gradient: temperature increase with depth ~25
         °C/km

5    I. Agents of Metamorphism
      (2) Pressure
      A. LITHOSTATIC PRESSURE results from the weight of
       overlying rocks and is applied equally from all sides
      Experienced by divers
6    I. Agents of Metamorphism
      B. DIFFERENTIAL PRESSURE results from unequal forces
       applied to the rock
      deformation

7    Metaconglomerate
8    I. Agents of Metamorphism
      (3) Fluid Activity
      increase the rate of chemical reactions
      water trapped in the pore space of sedimentary rocks
      magmatic fluids

9    II. Types of metamorphism
10   II. Types of Metamorphism
      (1) CONTACT METAMORPHISM
         produced when a body of magma alters the surrounding
          country rock
11   B. Protolith: Parent rock
12   II. Types of Metamorphism



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11   B. Protolith: Parent rock
12   II. Types of Metamorphism
      (2) DYNAMIC METAMORPHISM
      results from high differential pressures
      most often found near faults
      Result in MYLONITES
13   II. Types of Metamorphism
      (3) Regional Metamorphism
      produces most metamorphic rocks
      results from extreme heat, pressure and fluid activity
      covers large geographic areas
14   III. Metamorphic grade
      low, intermediate, and high grades of metamorphism are
       recognized with index minerals
15   IV. Metamorphic Texture
      1. FOLIATED Metamorphic Rocks
      A. Heat and differential pressure cause minerals to arrange
       themselves in parallel
      B. Slate-Phyllite-Schist-Gneiss

      Migmatites: “swirls”
16   Foliated textures
17   Foliated microtexture
18   IV. Metamorphic Texture
      2. NONFOLIATED Rocks
      A. minerals do not show a discernible preferred orientation
      B. Marble, quartzite, greenstone or hornfels
19   Nonfoliated microtextures
20   V. Metamorphic zones
21   V. Metamorphic zones
22   VI. Metamorphic Facies
      A pressure-temperature-depth diagram shows where various
       metamorphic facies occur
23   VII. Metamorphism
     the “big picture”
      plate tectonics, the growth of continents, and even climate
       change.

24   VII. Metamorphism and Plate Tectonics
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24   VII. Metamorphism and Plate Tectonics
25   VIII. Natural Resources




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