Aim: What are the different types of rocks.

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Aim What are the different types of rocks.

• Objective Ability classify the three basic
  types
• Vocabulary igneous, sedimentary, metamorphic,
  lava, magma, molten

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Is this lava or magma, or both?
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• Molten rock is liquid rock.
• Do you think molten rock is hot ?
• Inside the earth it is called magma
• When it reaches the outside lava

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Magma and/or lava forms igneous rock
Magma forms intrusive igneous rock Lava forms
extrusive igneous rock Whats the difference?
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Intrusive igneous rock large crystals

• Granite

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Intrusive igneous rock large crystals

• Granite
• Occurs when magma cools slowly !

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Extrusive igneous rock small crystals

• Basalt
• Occurs when lava cools quickly

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Igneous Rock
Intrusive Extrusive
Formed From Magam lava
Cools Slowly quickly
Results Large crystals Small crystals
Granite Basalt
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Sedimentary rocks show layers
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Formation

•  Sedimentary rocks are formed from pebbles, sand,
  silt, or clay
• Also formed from the shells or microscopic
  skeletons of dead sea organisms (1-celled)  
• Streams carry the tiny eroded fragments of stone
  and spread them out over a flood plain.
• Layers of these materials are built up over
  millions of years.  
• The layers of sediment turn into rock strata.

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Formation

• Sedimentary rocks are formed when eroded
  fragments of old rocks and dead organisms settle
  (usually in seas or rivers) to form a sediment.
  Over millions of years, layers of sediment build
  up and are buried one on top of the other.
• They are compressed, and their weight squeezes
  out the water.
• Eventually they become bonded together to form
  sedimentary rocks.

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Formation

• What are they like?Sedimentary rocks have a
  layered appearance. They may contain fossil
  remains of animals and plants that were trapped
  as the rocks formed. These fossils can be used to
  date the rock.
• Limestone, sandstone and mudstone are examples of
  sedimentary rocks.

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  A stream is carrying silt and clay into a
large lake or sea.
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Millions of years have gone by and there are many
layers of deposited sediment now. Some of the
sediment granules have been cemented together by
minerals that were dissolved in the water.  They
have turned into layers of rock
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Millions of years later, the water is no longer
there, Sedimentary rocks is exposed to the
atmosphere on Earth.
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Millions of years later, pressure from inside the
Earth may cause the layers of rock to rise or
fall BTW Which layer of rock is the oldest?
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Millions of years later, pressure from inside the
Earth may cause the layers of rock to rise or
fall BTW Which layer of rock is the oldest?
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Sometimes there is an earthquake or other fault
which make the layers disjoint
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Sometimes the older sedimentary layers are
covered by new volcanic activity magma or lava
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Metamorphic Rocks
Sometimes existing rock is subject to extreme
heat or pressure This changes the rock to a new
classification called metamorphic rock
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Metamorphic formation may occurs in areas where
existing layers of rock comes in contacts with
underground magma
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Metamorphic formation may form in areas where
existing layers of rock comes under great
pressure because they are under so many other
layers of rock.
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Rock Cycle
Rocks can and do change from one form to another.
The Rock Cycle is a model of these changes which
may occur over millions of year !