Chapter 2 (Part 4)

Chapter 2

 

IV. Metamorphic Rocks

   A.Changed form rocks

   B.Can form from

      1.Igneous rocks

      2.Sedimentary Rocks

      3.Other metamorphic rocks

   C.Degrees of Metamorphism 

      1.Show the rock's texture and mineralogy

      2.Types

         a.Low Grade(Shale becomes slate)

         b.High Grade (causes the original features to be obliterated)

   D. Metamorphic settings

      1.Regional metamorphism 

         a.over extensive areas

         b.Produces the greatest volume of metamorphic rock

      2.Contact metamorphism 

         a.Near mass of magma

         b."Brakes" surrounding rock

   E.Metamorphic agents 

      1.Heat

      2. Pressure 

         a. From burial

         b.From stress

      3.Chemically active fluids

         a.Water- most common

         b.Ion exchange among materials

   F.Textures

      1.Foliated

         a.Minerals are in a parallel alignment 

         b.Minerals are perpendicular to the force 

      2. Non-foliated

         a.Contain equidimensional crystals 

         b.Resembles a coarse igneous rock

   G.Classification

      1.Based on texture

      2.Two Groups

         a.Foliated Rocks 

            1.Slate

               a.Fine Grained 

               b.Splits easily

            2.Schists

               a.Strongly foliated 

               b. Platy

               c.Types based on composition 

            3.Gneiss 

               a. strong segregation of silicate minerals

               b.banded texture

         b. Non foliated rocks

            1.Marble

               a. Parent Rock- limestone

               b.Calcite Crystals

               c.Used as a building stone

               d.Variety of colors

            2.Quartite 

               a.Parent Rock - quartz

               b.Quartz grains are fused

   H. Resources from rocks and minerals 

      A. Metallic minerals

         1. Gold, sliver and copper 

         2.Produced by

            a.Igneous Processes 

            b. Metamorphic Processes

         3.Hydrothermal solutions

            a. Hot

            b.Contain metal rich fluids

            c.Cooling magma 

            d.Types

               1.Vein deposits 

               2. Disseminated deposits 

      B.Non-metallic minerals

         1. Make use of the materials

             a.Non metallic elements

             b. Physical or chemical properties

         2. Two broad groups

            a. Building materials (limestone/gypsum)

            b.Industrial Minerals (Flourite, corundum, sylvite)