Rocks cont.

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Rocks cont.

• Chapter 2

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Last time

• 2 minerals (quartz calcite)
• Igneous rocks
• Sedimentary rocks

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Metamorphic rocks

• Formed by transformation of other rocks
• End up with
• New minerals
• And/or texture changes

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Metamorphic textures

• Foliated alignment of minerals
• Rock looks banded/layered
• Nonfoliated random orientation of minerals

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Foliated or nonfoliated?
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Foliated metamorphic rocks

• Smallest minerals
• Slate
• Clue like shale/mudstone but harder

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Foliated metamorphic rocks

• Schist
• Shiny with bigger minerals

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Foliated metamorphic rocks

• Gneiss
• Big minerals
• Looks like a granite with bands of color

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Nonfoliated met. rocks

• Marble
• Made of calcite
• Best way to ID?

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Nonfoliated met. rocks

• Quartzite
• Can look like marble, but no fizz with acid

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Nonfoliated met. rocks

• Greenstone
• Clue green basalt

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Rock Cycle
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What rock is this?
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What rock is this?
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What rock is this?
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What rock is this?
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What rock is this?
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For met rocks, what did they start as?

• Greenstone
• Quartzite
• Marble
• Gneiss

• Basalt
• Sandstone
• Limestone
• Granite or mudstone

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For your rock

• What is it?
• How and where did it form?
• What part of the rock cycle has it seen?

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Layers of the solid Earth

• Crust
• Mantle
• Core

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Open March 28, 2003
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The core

• 16 of Earths volume
• Very dense (iron nickel)
• Inner core solid
• Outer core liquid

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The mantle

• 83 of Earths volume
• Less dense (iron, magnesium, silicon)
• Most of mantle solid but flows plastically

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The crust

• Outermost layer
• Ocean crust thinner and more dense
• Continental crust thick and less dense

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The crust

• Crust divided in to plates
• Plates move on top of plastic mantle
• Concept plate tectonic theory
• Explains where all rocks form and why

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Reminder of time period for project

• Choose top 2 choices of time period (Cambrian
  through Quaternary) due next Friday
• Once in group, decide exact topic