Earths Treasure Trove

Document Sample
Earths Treasure Trove Powered By Docstoc
					ELEMENTS, MINERALS, AND
                 ROCKS
 The  layers of the lithosphere are made up
  of elements, minerals, and rocks.
 Elements:
  • Substances that cannot be broken apart in any
    way by chemical or physical means
  • They are the building blocks of minerals
  • Example: Carbon and oxygen
 Inorganic compounds of one or more
  elements found naturally in the lithosphere
 Minerals combine in infinite variety to make
  up rocks
 Of the 92 elements found in nature, only
  eight form most of the earth’s crust
 The combination of one or more elements
  creates a mineral
    Ex. Of one element – coal, made up of pure carbon
 Examples: gold, silver, and copper
 Often identified with a chemical formula
    Ex. Silicon dioxide (SiO2) is quartz
 When several minerals are cemented
 together to form rocks
   Ex. Granite is made up of quartz, mica, and orthoclase
    or plagioclase feldspar.
 Rocks  and minerals seem indestructible,
  but they are actually constantly changing.
 Existing rocks are being worn down and
  crushed by natural processes, and new
  rocks are constantly being formed as
  sediments are cemented together or as
  volcanoes spew lava into the air.
 Rocks are classified as either igneous,
  sedimentary, or metamorphic, according
  to how they were created.
                            % of the Earth’s Crust

                            Mass            Volume
   Element        Formula
Oxygen       O              46%               91%
Silicon      Si             28%               1%
Aluminum     Al             8%                1%
Iron         Fe             5%                1%
Calcium      Ca             4%                1%
Sodium       Na             3%                2%
Potassium    K              3%                2%
Magnesium    Mg             2%                <1%
Carbon       C              <1%               <1%
Sulphur      S              <1%               <1%
Lead         Pb             <1%               <1%
Hydrogen     H              <1%               <1%
 Created  from molten rock, or magma,
  deep within the crust and upper mantle.
 These rocks are often found on the
  earth’s surface in one of two ways: via
  volcano eruptions or erosion
 Formed   when a volcano erupts and molten
  rock, or lava, flows over the earth’s surface.
 When it cools, new rock is formed.
 Depending on the minerals in the lava and
  the speed in which it cools, a wide variety of
  different igneous rocks can be created.
 Ex. Obsidian: Resembling black glass, this
  rock is formed when lava is cooled so
  rapidly that crystals do not get a chance to
  form.
 Originate when molten rock solidifies deep
  within the lithosphere
 These plutonic rocks eventually reach the
  surface as erosion gradually wears away the rock
  above it
 Much of the igneous rock in Canada was formed
  this way.
 Ex. Granite, takes on different colours depending
  on how quickly they formed and what type of
  material they are made up of. Granite is made
  up of either pick feldspar or gray feldspar, plus
  quartz, hornblende, and mica.
 Created from deposits of broken-up material
  (sediments) that accumulate in oceans and lakes,
  deposited by weathering (wind, glaciers, or water)
  and erosion.
 Sediments are transformed into rock, by being
  compacted and cemented together.
     Compaction occurs when new layers of sediments are deposited on
      top of older layers. The weight of upper layers squeezes out any
      spaces between particles that make up the layers beneath, and
      presses the weathered material tightly together.
     Cementation occurs when minerals, dissolved in water, filter
      through the sediment. At a certain temperature and pressure, the
      minerals precipitate out of the water solution and remain in the
      spaces between the rock particles, cementing the particles together.
 Classified by their origin and texture.
 There are 3 different types of sedimentary rock:
  clastic, chemical, and biogenic.
 All three types of sedimentary rocks can be found
  mixed together.
 Formed  when accumulations of stones and
  smaller pieces of weathered rock are
  cemented together naturally.
 Textures range from:
    Shale (made from clay deposited in a lake – very smooth)
    Sandstone (made from sand deposited in moving water –
     fine particles, rough texture)
    Conglomerate (stones and large boulders deposited in fast
     moving water and cemented together – rough, large
     particles)
 Ex. Shale, sandstone, and        Breccia
 Formed     from chemical processes
 Classified by texture and source
  material.
 Ex. Gypsum, formed when water
  evaporated, leaving the dissolved salts
  on the sea floor.
 Flint, is a hard chemical sedimentary
  rock that forms from quartz crystals that
  are cemented together by fine silica gel.
 Formed   from living organisms
 Most common examples are dolomite
  and limestone, which are both created
  from the shell and skeletal remains of tiny
  sea creatures. This leaves a calcium
  deposit.
 Calcium carbonate cements these
  fragments together, creating limestone.
 Dolomite is formed when magnesium
  carbonate cements them together.
   “Meta” means change
   “Morph” means shape
   Metamorphic rocks changes more than just their shape
   Estimated that 85% of the upper crust is made of
    metamorphic rock, buried under sedimentary rock
   They change in mineral composition, structure, and texture
    as a result of the great pressure and heat that exist in the
    lithosphere.
       The amount of change depends on the amount of heat (over 300oC) and
        pressure exerted on it.
   Formed in places where there is enormous pressure and
   More types of metamorphic rock than there are igneous or
    sedimentary rocks. Each sedimentary and igneous rock has
    at least one metamorphic equivalent.
   Ex. Marble, gneiss, schist, and quartzite
   Hard to identify because they are like igneous rocks, but
    they are different because of a banded structure called:
    Foliation
       When pressure is intense, minerals may align themselves in layers within the
        rock.
   There are two major types: Contact and Dynamic
1.   Contact Metamorphic Rock
     • Those that change as a result of the heat given off
      during the formation of intrusive igneous rocks

2.   Dynamic Metamorphic Rock
     • Formed when compressed by the weight of rock
      layers above them or by tectonic forces.
      to page 89 in your textbook and
 Refer
 complete the diagram of the rock cycle

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:10/6/2012
language:simple
pages:21