Earths Treasure Trove: Elements, Minerals and Rocks

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Earths Treasure TroveElements, Minerals and
Rocks

• Chapter 6

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What is the Lithosphere Made of?

• The layers of the lithosphere are made of
• Elements
• substances that cannot be broken apart in any way
  by chemical or physical means.
• For example Carbon, Oxygen
• Minerals
• compounds of one or more elements
• For example Coal, Carbon dioxide
• Rocks
• minerals combine in an infinite variety to make
  up rocks.

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Types of Rock

• Three types
• Igneous
• Sedimentary
• Metamorphic

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Igneous Rocks

• Created from molten rock or magma in the earths
  crust or asthenosphere
• These rocks reach the earths surface via
  volcanic eruptions or by erosion
• Extrusive Igneous Rocks form when lava flows on
  earths surface and then hardens into new rock
• Intrusive Igneous Rocks form when magma
  solidifies inside the lithosphere

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Sedimentary Rock

• Created from deposits of broken-up material that
  accumulates in oceans and lakes
• Three types
• Clastic Sedimentary Rock formed when stones and
  smaller pieces of weathered rock are cemented
  together naturally
• Chemical Sedimentary Rock formed from chemical
  processes.
• Biogenic Sedimentary Rock formed from the
  living organisms

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Sedimentary Rock

• Sediment builds up when layers of materials are
  deposited by rivers, glaciers, and other agents
• First rock is weathered or broken up into smaller
  pieces
• Then its transferred to another place by wind
  glaciers or water before finally being deposited
• Layers are created as more and more weathered
  material accumulates over time until thick
  deposits of sedimentary rock are formed

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Sedimentary Rock

• For sediment to be transformed into rock it must
  be compacted and cemented together
• Compaction new layers are deposited over old
  ones. The weight of the upper layers squeezes out
  all the spaces between the particles in the
  layers beneath
• Cementation occurs when minerals, dissolved in
  water filter through the sediment. At a certain
  pressure and temperature the minerals precipitate
  out of the water and act like glue to cement the
  sediments together.

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Metamorphic Rocks

• Meta means change
• Morph means shape
• These rocks form when sedimentary and igneous
  rocks are subjected to heat and pressure and
  morph into new rocks
• For example sandstone turns to quartzite,
  limestone turns to marble
• 85 of the earths crust is made of metamorphic
  rocks

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Metamorphic Rock

• Two types
• Contact Metamorphic Rocks those that change as
  a result of the heat given off during the
  formation of intrusive igneous rock
• Dynamic Metamorphic Rocks formed when they are
  compressed by the weight of the layers above them
  or by tectonic forces

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The Rock Cycle
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Building Resources

• Rocks and minerals provide many of the raw
  materials used to manufacture a wide range of
  consumer items
• Examples
• graphite in your pencil
• Gold in your jewelry
• Metal in the desk legs
• chalk