Rocks

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Rocks

• A solid material made up of 1 or more minerals,
  or other things including the remains of
  once-living things.

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• Earths rocks are made up of about 20 minerals.
• A rock can have several minerals or only one.

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Classify Rocks

• Color color of rock depends on the minerals that
  make it up.
• Texture size, shape, arrangement of the grains
• Large grains coarse texture
• Small grains fine texture

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• Composition The minerals the rock is made up of
• Easier to ID course grained rocks
• How/where rocks are formed -

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Classify Rocks

• 3 Major groups
• Igneous
• Sedimentary
• Metamorphic

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3 Main Types of Rocks
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Igneous Rock
http//www.fi.edu/fellows/payton/rocks/create/igne
ous.htm
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Igneous Rock

• Fire formed
• Forms when magma or lava cools and hardens
• Intrusive
• Extrusive

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Intrusive Igneous Rock

• Cools and hardens beneath the surface.
• Coarse grained. Larger mineral crystals.
• Forms much Continental Crust.
• Ex Granite, diorite, pegmatite

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Extrusive Igneous Rock

• Forms from Lava on the surface of the Earth.
• Fine-grained. Small Crystals Cool quickly
  Basalt most common Makes up the oceanic crust.
• Ex Obsidian, pumice, andesite

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• Granite - Intrusive

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• Obsidian - extrusive

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Sedimentary Rock
http//www.fi.edu/fellows/payton/rocks/create/sedi
ment.htm
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Sedimentary Rock

• Form in places where there was once water
• Form from sediment that is compacted and cemented
  together
• Takes millions of years to form

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Sediments

• Particles of rock, minerals or organic material.
• Sand, gravel, seashells, leaves, dead plants
  animals.

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• Weathering - The chemical and physical processes
  that break down rock at Earths surface.
• Erosion wind, water, gravity carries sediments
  to a new place.
• .

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Deposition when the water stops moving and
drops off the sediments Compaction slowly
the layers of sediment press down on top of other
layers
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• .
• Cementation when the layers are stuck
  together.
• Water evaporates, leaving minerals behind which
  glue the sediments together

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3 Types of Sedimentary Rock

• Clastic Rock Made up of particles of
  pre-existing rock
• Can form from igneous, metamorphic or other
  sedimentary rocks
• Ex sandstone, conglomerate

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Sandstone
Sedimentary, Clastic Rock Sandstone
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Sedimentary, Clastic Rock Conglomerate
Conglomerate
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Chemical Sedimentary Rock

• Form due to chemical reaction Evaporites
  http//geology.campus.ad.csulb.edu/people/bperry/S
  edimentary20Rocks20Tour/chemical_sedimentary_roc
  ks.htm
• Can occur in oceans, lakes, caves and hot
  springs.
• Ex limestone, halite, calcite

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Limestone forming Coral Reefs off the coast of
China
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Limestone found in Arizona Once part of a reef
under water
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Limestone in Guadelupe Mnts in West Texas 280
million years ago was under water now 8,000 ft
above sea level.
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Sedimentary, Chemical Rock Halite
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Organic SedimentaryRock

• Form when organic material sea shells, dead
  animals and plant material is compacted and
  cemented together
• Ex coquina, coal, anthacite

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Coquina

• seashellsbymillhill.com
• 900  769 - Made of tiny coquina seashells

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Metamorphic Rock
http//www.fi.edu/fellows/payton/rocks/create/meta
morph.htm
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Metamorphic Rock

• Meta Change
• Morph - form
• Original rock igneous, sedimentary, metamorphic
  is changed by intense heat and pressure causing
  physical or chemical changes

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Metamorphic Rock

• Can form when
• rock is deep within earths surface subjected
  to high temps and pressure of layers above
• Tectonic processes continental plates colliding
• Rock is heated by molten magma nearby

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Metamorphic Rock

• One type of rock is changed into another type of
  rock
• Igneous granite is changed into metamorphic
  gneiss
• Sedimentary rock sandstone changes into quartzite
  

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Metamorphic Rock

• 2 Types foliated and non-foliated
• Foliated- banded
• Examples - Gneiss, schist, slate
• Non-foliated not banded
• Examples marble, quartzite

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• Gneiss - foliated

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• Schist - foliated

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• Marble non-foliated

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• Quartzite non-foliated

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• What type of rock do I have
• http//www.minsocam.org/MSA/K12/rkcycle/typeofrock
  .html
• Rock cycle real pix and describe steps
• http//www.open2.net/geologytoolkit/rockcycle_embe
  dded.html
• Good click and drag animation
• http//www.kscience.co.uk/animations/rock_cycle.ht
  m
• Pictures of Different Rocks Rock Picture
  Gallery
• http//geology.about.com/library/bl/images/blrocki
  ndex.htm