ROCKS

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ROCKS
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What is a rock?
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What is a rock?

• Made of entirely one mineral or several minerals.
  
• Could contain organic matter (composed of living
  material, usually carbon based).
• The chemical make-up of the rock may vary from
  one sample to another.

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Types of Rocks

• What are the three classes of rocks?

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Types of Rocks

• What are the three classes of rocks?
• 1. Igneous Rocks
• 2. Sedimentary Rocks
• 3. Metamorphic Rocks

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Igneous Rocks

• Name comes from the Latin word ignis meaning
  from fire.
• Formed when super hot magma or lava cools.
• There are seven different classes based on
  chemical composition of the igneous rock.

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Types of Igneous Rocks

• Extrusive Igneous Rocks
• Formed from lava that quickly solidifies at the
  cooler surface.
• Produces fine-grained rocks.
• Ex. basalt and rhyolite

david-amador.com
geology.com
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Types of Igneous Rocks

• Intrusive Igneous Rocks
• Trapped magma under the crust solidifies slowly.
• Intrusive rocks are composed of larger crystals
  because form slower.
• Larger crystals give these rocks a rougher
  texture
• Ex. granite

• Mount Rushmore is carved from granite in the
  Black Hills of South Dakota.

Mount Rushmore is carved from granite in the
Black Hills of South Dakota.
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Igneous Rock

• The most common known igneous rock is granite.
• It is composed almost entirely of feldspar and
  quartz

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Igneous Rocks Mafic vs. Felsic

• Felsic chemically composed of potassium,
  feldspar, and large amounts of quartz.

• Mafic chemically composed of iron and
  magnesium, and smaller amounts of quartz.

csmres.jmu.edu
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Bell Ringer Rocks

• What is the difference between intrusive and
  extrusive igneous rocks?
• T or F Intrusive igneous rocks are composed
  of larger crystals then extrusive igneous rocks.
• Would mafic or felsic magma be magnetic? Explain
  your answer.

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Igneous Rock Formations

• Extrusive Igneous Structues
• volcanoes
• Intrusive Igenous Structures
• batholiths
• laccoliths
• sills
• dikes

indiana.edu
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Sedimentary Rocks

• All sedimentary rocks are made of materials
  called sediments deposited by natural and
  chemical processes.
• Sediments become cemented or compacted together
  over time forming a solid rock

Uluru (Ayers Rock) in Australia, the world's
largest monolith, is made of sandstone.
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Types of Sediments

• Tiny grains of sand
• Broken pieces of rock along the bottom of a
  stream
• Fragments of seashells
• Layers of mud
• Organic matter (plant and animal remains)

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Sediments and Sedimentary Rocks

• Gravity, water, or wind carries them to a
  destination.
• Sediments deposit in layers over time. (strata
  layers)
• Loosely deposited sediments eventually form a
  solid rock by
• 1.Compaction sediments squeezed together by
  gravity/pressure.
• 2. Cementation sediments glued together by
  minerals deposited by water.

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Sedimentary Rock

• The most common sedimentary rock is limestone.
• Develops from living remains (shells, mollusks)
• Coal is another example of a sedimentary rock
  derived from organic remains.

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Sedimentary Rock
Ripple marks formed in the sand by wind

• Often preserve some characteristics from which
  they were formed.
• Ripple marks formed in the sand will appear in
  the rock formed from the sand deposits.

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Sedimentary Rocks

• The source of most fossil remains.
• The age of a rock can be determined by studying
  the fossils within it.(Radiometric Dating)
• Identify when prehistoric organisms and
  vegetation thrived and became extinct.

Fossilized Leaves
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Sedimentary Rocks

• The diverse colors within the sedimentary layers
  (strata) gives scientists an idea of their
  chemical make-up.
• The red and pink bands in the Grand Canyon
  exhibit the iron found in the sediment.

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Sedimentary Rocks Location

• Sedimentary rocks cover almost all of the ocean
  floor and about three-fourths of Earth's surface
  land area.

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Metamorphic Rock

• Metamorphism change in the chemical make-up of
  rocks
• Heat, pressure, and hot fluids cause rocks to
  change into other rocks.
• Where would this most likely occur?

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Metamorphic Rock

• Heat, pressure, and hot fluids cause rocks to
  change into other rocks.
• Where would this most likely occur? within the
  Earth
• at subduction zones

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Metamorphic Rock
Formed from compression of Tectonic plates
The geologic processes that created the North
Cascades changed the original rock into
metamorphic rock.
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Types of Metamorphic Rock

• Slate is a common form that is easily split into
  slabs
• Gneiss (pronounced nice) contains light and
  dark bands
• Granite is also a common type

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The Rock Cycle

• Almost all of the rocks that compose the Earths
  crust today are made of the same stuff as the
  rocks that dinosaurs and other ancient life forms
  walked, crawled, or swam over. While the
  stuff(matter) that rocks are made of has changed,
  the rocks themselves, have not. Over time rocks
  are recycled into other rocks.

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The Rock Cycle
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The Rock Cycle