Rocks

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Rocks
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We Are the Rocks
We are the rocks...Igneous. We are the
rocks...Metamorphic. We are the
rocks...Sedimentary. We are the rocks...in the
Rock Cycle! I am an igneous rock. I was very
hot when I was magma. Over time I cooled and
became a rock. I was magma. Minerals combined
to form my Igneous rock. I have an Igneous
friend who was just like me...from magma. The
name is El Capitan in Yosemite. He was magma.
Minerals combined to form that Igneous rock.
Resource Songs for Teaching
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• Question
• What primary processes are involved in the rock
  cycle?

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Rock

• Mixture of minerals, volcanic glass, organic
  matter, or other material.

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Rock Cycle

• Model showing processes that create and change
  rock.
• A continuous and dynamic process.

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Animation of Rock Cycle
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Three Types of Rock

• Sedimentary rock can be changed by heat and
  pressure into metamorphic rock.
• Metamorphic- rock can melt and cool to form
  igneous rock.
• Igneous rock can be broken into fragments that
  may later form sedimentary rock.

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Conservation of Matter

• Rock cycle never destroys elements of rocks but
  merely redistributes them.
• James Hutton recognized the rock cycle in 1788 by
  observing Siccar Point, Scotland.

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Igneous Rock

• Igneous rocks form from magma found deep under
  Earths surface.
• Magma reaching the surface flows from a volcano
  as lava.
• Magma trapped below the surface forms
  large-grained intrusive igneous rock when it
  cools.
• Magma cooling at or near Earths surface forms
  small-grained extrusive igneous rock.

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Igneous Rock
Resource Rock Hounds with Rocky
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Crystal Size

• Large or small can help identify an igneous rock
  as intrusive or extrusive.
• Volcanic glass rocks cool so quickly that few
  crystals form.

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Igneous Rocks are classified

• Where they formed
• Under the Earths surface intrusive
• At or near the Earths surface - extrusive

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Magma Type

• Basaltic
• Granitic
• Andesitic

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Basaltic Igneous Rock

• Dark-colored and dense.
• Contain iron and magnesium but very little
  silica.
• Basaltic lava flows freely from a volcano.

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Granitic Igneous Rocks

• Lower density and lighter color
• Contain more silica and less iron and magnesium
• Granitic magma is thick and stiff

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Andesitic Rocks

• More balance composition of minerals and density
  than basaltic or granitic rocks.

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Igneous Rocks
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How Sedimentary Rock Is Formed

• Sediments

• Moved by wind, water, ice or gravity

• Rock Fragments
• Mineral grains
• Bits of plants and animal remains

Resource Rock Hounds with Rocky
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Classified

• Detrital sedimentary rocks made from broken
  fragments of other rocks.
• When layers of small sediments stick together
  because of pressure, compaction occurs.
• When water and other minerals move through open
  spaces between larger sediments, gluing them
  together, cementation occurs.
• Often have a granular texture.

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Rocks are named according to size and shape of
sediments.

• Sediment size can be large like gravel or small
  like clay.
• Sediments can be well-rounded or have sharp
  angles.

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Chemical Sedimentary Rocks

• Non-clastic rocks formed when dissolved minerals
  came out of solution.
• Limestone forms from calcite, which was calcium
  carbonate in solution.
• Rock salt forms from halite, which was salt in
  solution.

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Organic Sedimentary Rocks

• Made from once living plants or animals
• Chalk made of microscopic calcite-shell remains
  of animals
• Coal made of plant remains, chemically changed
  by microorganisms and compacted over millions of
  years

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Sedimentary Rocks
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Metamorphic Rocks

• Changed by temperature, pressure, and hot fluids.
• Sometimes temperature and pressure are great
  enough to melt rock, forming magma.
• Sometimes pressure flattens mineral grains in
  rocks without melting them.
• As pressure and temperature continue to increase
  over time, one type of rock can change into
  several different metamorphic rocks.
• Hot, water rich fluids can move through rock,
  chemically changing it.

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Metamorphic Rock
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Classification of Metamorphic Rocks

• By composition and texture
• Foliated texture mineral grains flatten and
  line up in parallel layers or bands
• Nonfoliated texture mineral grains grow and
  rearrange but do not form layers.

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Metamorphic Rocks