Download Rocks

Rocks
Pieces of the Earth’s crust.
Types of Rocks
• Igneous- Rocks that formed from the fiery
depths of the Earth. They form from magma and
lava.
– Extrusive
– Intrusive
• Sedimentary- Rocks that formed from the
eroded sediment of other rocks through
lithification (compaction, cementation)
• Metamorphic- Rocks that have been changed
or morphed through heat and pressure
Igneous Rock
• Rock that forms from cooled magma or
lava.
• Crystalline or glassy structure
• Extrusive or Intrusive
• Felsic- Thick viscous, silica rich, light
colored
• Mafic- Hot, thin, fluid-like, often Iron rich,
dark colored
Igneous Rock
• Igneous Rock Examples
Igneous Rock
• Structure depends upon freezing
temperature of rock and rate of cooling
• Bowen’s reaction series
– High freezing temperatures crystallize first
– Depends upon composition
– Discontinuous series- Mafic magma
• Olivine, pyroxine, amphibole, biotite, potassium feldspar, muscovite,
quartz
– Continuous series- Felsic magma
• Calcium rich, calcium/sodium rich, sodium rich
Bowen’s Reaction Series
Igneous Rocks
• Crystal size depends upon rate of cooling
• Fast cooling lava produces small crystals,
or even no crystals (glassy)
• Slow cooling magma produces large
crystals.
• When magma cools at different rates,
large and small crystals may result
creating porphoritic rock
Igneous Rocks
• Rock Families
– Read about the 3 main types of rock families
in your text. pgs 123-125
– Summarize each type of igneous rock family
in your notes
Igneous Families
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Granite (Felsic)
Gabbro (Mafic)
Diorite (Intermediate)
Peridotite (Ultramafic)
Granite Family
• Mostly coarse grained felsic rocks that are
generally light in color. Most granite family
rocks cool slowly due to the thick sticky
magma that they form from.
Gabbro Family
• Dark, dense coarse grained mafic rocks.
• Contain the minerals pyroxene, olivine,
plagioclase feldspar, amphibole, and
biotite.
Diorite Family
• A mixture of felsic and mafic rock.
• Darker than granites but lighter than
gabbros.
Peridotite Family
• Dense coarse grained ultramafic rock.
• Contain the minerals olivine and pyroxene.
Sedimentary Rocks
• Sedimentary rocks form from fragments of
other rocks producing clastic rocks.
• Through weathering and erosion,
sediment is carried by wind and water.
• This sediment is eventually deposited.
• Deposition occurs when the moving water
or wind slows down.
Sedimentary Rock
• Deposited material often gets sorted by
size.
• Large sediment often only makes it part
way down rivers.
• Small sediment makes it to the mouth of
rivers.
• Fine silts and clays gets carried out to the
middle of the oceans and lakes
Sedimentary Rock
Sedimentary Rocks
• Eventually material is formed into rock
through lithification
• This sorting gives rise to different types of
clastic rock such as
– Conglomerate
– Sandstone
– Shale
Conglomerate
Sandstone
The layering that is shown here is called stratification.
Shale
Sedimentary Rock
• Other types of sedimentary rock can be
formed through chemical processes and
organic material
– Limestone (organic and chemical)
– Halite (chemical)
– Coquina (organic)
Limestone
Halite
Coquina
Sedimentary Rock
• Sedimentary Rock Examples
Metamorphic Rock
• Metamorphic rock is rock that has been
changed over time due to heat and
pressure.
• Crystals get squished and the texture
becomes foliated
• Foliated metamorphic rocks have a
layered or banded appearance that is
produced by exposure to heat and
directed pressure.
Metamorphic Rock Foliation
Crystal are flattened
Orientation becomes aligned
Metamorphic Rock
• Metamorphic Rock Examples
• Foliation process animation