The Story of Tiny Pebble

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The Story of Tiny Pebble

• By Tyler Brown

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Tiny Pebble is Born

• Tiny Pebble is a tiny piece of sandstone. He
  doesnt know he is made of sandstone, so he
  thinks that he isnt any good. Tiny Pebble has
  friends, but he thinks all the other minerals are
  rare gems. Tiny Pebble thinks he isnt worth
  anything because he doesnt know he is made of
  sandstone, which has tiny pieces of quartz
  embedded in it.

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Types of Rocks

• Tiny Pebble is made of sandstone, which is a
  sedimentary rock. This means he is a rock
  fragment that has been moved by nature. Some of
  his friends are igneous rocks and others are
  metamorphic. Igneous rocks form when magma cools
  or hardens. His metamorphic rock friends form
  when heat, pressure, or fluids act on igneous,
  sedimentary, or other metamorphic rock and
  affects its form or composition, or both.

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Compaction and Cementation

• Sedimentary rocks, like Tiny Pebble, can be
  formed from compaction and cementation.
  Compaction occurs when layers of small sediments
  are compressed by the weight of the layers above
  them. Tiny Pebble was formed by compaction.
  Cementation occurs when large sediments are held
  together by natural cements that are produced
  when water soaks through rock and soil.

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Rock Cycle

• Tiny Pebble is a sedimentary rock. This means he
  was originally an igneous rock, but weather and
  erosion broke off sediments from the igneous
  rock. With compaction and cementation, these
  sediments became a sedimentary rock. If heat and
  pressure are applied to Tiny Pebble and his
  igneous rock friends, theyll become a
  metamorphic rock. All three types of rocks can
  become magma if they melt and all 3 can become
  sediments with weathering and erosions. When the
  magma cools it becomes igneous rock.

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What Does Intrusive and Extrusive Mean?

• Tiny Pebble has many igneous rock friends. Some
  of them are intrusive and some of them are
  extrusive. Intrusive igneous rocks, like granite,
  form when magma cools slowly beneath earths
  surface. Extrusive igneous rocks, like basalt,
  form when magma cools quickly at or near earths
  surface. When magma reaches earths surface out
  of a volcano, it becomes lava.

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What Types of Magma are There?

• Tiny Pebble is scared of lava. When lava is under
  earths surface, it is classified as magma. When
  magma is above earths surface, it is called
  lava. There are three types of magma basaltic,
  granitic, and andesitic. Basaltic magma is dark
  colored and dense. It contains iron and
  magnesium, but very little silica. Granitic magma
  has a lower density and lighter color. Granitic
  magma is rich in silica but has very little iron
  and magnesium. Granitic magma is thick and stiff.

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Metamorphic Rocks

• Tiny Pebble is most scared of the metamorphic
  rocks. They have been put under a lot of heat and
  pressure, so they are always angry. Metamorphic
  rocks are classified by their composition and
  texture.

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Classification of Metamorphic Rocks

• Metamorphic rocks are classified into two groups
  foliated and nonfoliated. Foliated metamorphic
  rocks, like quartzite, have mineral grains that
  flatten and line up in parallel layers.
  Nonfoliated metamorphic rocks have mineral grains
  that grow and rearrange, but dont form layers.

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A Walk On the Volcano

• One day Tiny Pebble was out for a walk on a
  volcano when he ran into one of his metamorphic
  rock friends. I wish I was made of sandstone
  like you, the other rock said. Im made of
  sandstone? Tiny pebble asked. Yes, silly, you
  also have pieces of quartz embedded all over the
  outside of your body, his friend said. Thats
  awesome, Tiny Pebble said. Tiny Pebble was more
  self-confident from that day on and made lots of
  new friends.