Rocks

1
Rocks
2
The Rock Cycle
Interactions between water, air and land can
cause rocks to change from one form to another.
This process is called the ROCK CYCLE.
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The Rock Cycle the basics

• Rocks are broken into small pieces (sediment)
• Sediment gets cemented together (makes different
  rocks)
• Rocks get subjected to a lot of heat and pressure
  (makes different rocks)
• Magma and lava cool (makes different rocks)

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Types of RocksRocks any naturally occuring
solid mass of mineral or mineral-like material
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Sedimentary RocksHow They are Made

1. Wind and water break down the earth
2. Bits of earth settle in lakes and rivers
3. Layers are formed and build up
4. Pressure and time turn the layers to rock

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Types of Sedimentary Rocks
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Sedimentary Rock Formation

• Weathering breaks rock into sediments
• Erosion weathering combined with movement of
  rock sediment (Water, wind, ice, gravity)
• Deposition process of sediment being moved by
  an element of erosion to another place
• Compaction sediments are squeezed together
• Cementation dissolved minerals fill in the
  spaces between sediments

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Sedimentary Rock Classification

• Clastic made from weathered bits of rock and
  grouped according to the size of sediments in the
  rock EX. Shale and Breccia
• Chemical made from dissolved minerals falling
  out of solution. This usually happens when water
  evaporates. EX. Limestone and Rock Salt

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Metamorphic RocksWhat are They?

1. Rocks that have changed
2. They were once igneous or sedimentary
3. Pressure and heat changed the rocks

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Types of Metamorphic Rocks
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Metamorphic Rock Formation

• Occurs when temperature and pressure are high in
  the Earths surface and mantle
• Contact Metamorphism magma intrudes into
  existing rock, changes in the rock occur where
  the magma touches the existing rock
• Regional Metamorphism mountain building large
  scale changes
• Agents of Metamorphism heat, pressure, reaction
  to water

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Metamorphic Rocks Classification

• Foliated layered looking. These layers have
  different densities EX. Shale
• Non-foliated no layers or bands. Usually have
  only one mineral EX. Marble

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Igneous RocksWhat are They?

1. Fire Rocks
2. Formed underground by trapped, cooled magma
3. Formed above ground when volcanoes erupt and
   magma cools

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Types of Igneous Rocks
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Classification Igneous Rocks

• Intrusive made beneath the Earths surface
  (from magma)
• Extrusive made above the Earths surface (from
  lava)
• REMEMBER magma and lava are the same thing.
  Except we call magma lave when it reaches the
  Earths Surface

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Classification Igneous Rocks - cont

• Course-grained texture large crystals, slow
  cooling
• Fine-grained texture small crystals, fast
  cooling
• Glassy texture little to no crystals, crazy fast
  cooling
• Porphyritic texture large and small crystals
  due to cooling that occurs over thousands of
  years

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Igneous Rock Composition

• Granitic makes up continental crust
• Basaltic makes up the ocean floor
• These rocks are made of different concentrations
  of materials like silicate.
• Granitic - high silicate concentration.
• Basaltic - low silicate concentration.
• These differences effect rock density. Rock
  density determines how plates of rock move.
  Important for when we talk about Plate Tectonics.