Chapter 10 ROCKS

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Chapter 10ROCKS
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Ch. 10.1 Rocks and the Rock Cycle

• Magma is the parent material for all rocks.
• There are three types of rocks, classified by how
  they are formed.

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Igneous Rocks

• Formed when magma or lava cools and hardens.
• Igneous is from the Latin term from fire.

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Sedimentary Rock

• Formed when small fragments of rock or organic
  material harden after being compressed and
  cemented together.

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Metamorphic Rock

• Forms when heat and or pressure, or chemical
  processes change the form of existing rock.

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The Rock Cycle

• Any type of rock can be changed into any other
  kind of rock and back again.
• Processes are
• Melting and coolingigneous.
• Compaction and cementationsedimentary.
• Heat and pressuremetamorphic.

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Characteristics of Igneous Rocks

• Large or small crystals depending on cooling
  rate. The slower the cooling rate, the larger
  the crystals.
• Color depends on lava or magma typefelsic
  produces lighter rocks mafic produces darker
  rocks.
• May have trapped gas bubbles (pumice and scoria).

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• Generally composed of silicate minerals.

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Characteristics of Sedimentary Rocks

• Form from cemented together rock fragments,
  organic material, or from minerals that
  precipitate out of water.
• May have layered structure from deposition of
  various kinds of sediment deposited in silt beds.
• Moving wind or water may cause ripple marks.
• May contain fossilsremains or traces of ancient
  plants or animals.

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Characteristics of Metamorphic Rock

• Local volcanism may cause contact metamorphism.
• Tectonic activity may cause widespread regional
  metamorphism. Usually deep within the earth.
• May have enlarged or alternating bands of
  crystals (foliated).
• May change soft sedimentary rock into hard,
  durable rock.