Quiz: True or False and why

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Quiz True or False (and why)

• Coal is a mineral.
• Covalent bonds involve one atom giving an
  electron to another atom.
• This mineral
• exhibits cleavage

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Rocks(Part 1 of 3)
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What Are Rocks?

• Solid aggregate of one or more minerals
• Can also include organic sediments (ex coal)

Potassium Feldspar (Orthoclase)
Quartz
Biotite Mica
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Three Types of Rocks

• Igneous Rocks
• Cooled (solidified) from a liquid magma
• Sedimentary Rocks
• Metamorphic Rocks

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Igneous Rocks(from melts to solids)
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How do magmas form?

• Most information comes from experiments
• (literally guys melting rocks in a lab)
• Minerals melt at temperatures (T) above their
  melting point
• Increase in heat adds energy to bonds
• When it is sufficient, bonds break ? liquid

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Rocks dont all melt at once

• Minerals that compose rocks melt at different
  temperatures
• So, some minerals melt and others stay solid
• Moms ol chocolate chip cookies

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Partial Melting

• Melts of different compositions generated by
  changing amount of melt created
• This is why not all igneous rocks look the same
• Depends on composition, pressure
• Also occurs as magmas cool

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Composition of Original Rock

• Rocks rich in calcium (Ca), magnesium (Mg), and
  iron (Fe)
• Minerals with high melting temperatures
• Ex Olivine
• Rocks rich in potassium (K), silica (Si), and
  sodium (Na)
• Minerals with low melting temperatures
• Ex Quartz

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Pressure (P)

• Pressure increases with depth
• Bonds, more compact, harder to break
• A mineral at surface melts at 1000C might melt
  at 1300C if deep in the Earth
• As temp and pressure increase with depth, melting
  occurs 100-350 km down (600-1400C)

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Magma Storage Hot Bodies

• Rocks expand 10 in volume as they melt
• Given time space, liquids move upward because
  they are less dense (ex balloons)
• Move through empty spaces
• Collect where the density is equal, shallow

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Classifying Igneous Rocks

• When magma/lava solidifies, minerals form
• Igneous rock texture
• Size, shape, and arrangement of Minerals

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Intrusive (or plutonic) Igneous Rocks

• If molten magma cools beneath the surface
• Slow cooling allows for growth of large crystals
• Ex Granite

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Extrusive (or volcanic) Igneous Rocks

• Rapid cooling produces small crystals/glass
• Eruptions onto the Earths surface

Obsidian
Tuff
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Felsic
Mafic
Ultramafic
Intermediate
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Common Igneous Rocks
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Homework

• Read pgs. 47-51, 52-53
• Due Wednesday
• 6 pts Review Questions (pg 71) 5, 7, 8
• 4 pts For Discussion (pg 71) 2 (THINK)