4. Most prevalent in Earth’s crust
Intrusive - formed underground when magma (melted rock, temps
between 1,500 and 2,400 degrees F) cools
Granite
Extrusive - formed above ground when lava (melted rock) erupts from
volcanos and cools on the surface
Basalt, Obsidian
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5. Formed by deposits of material on the Earth’s surface or within
bodies of water (Sedimentation).
Sediment consists of small weathered particles of other rocks or
the weathered shells of sea animals.
Wind and rain work on the exposed rock, particles are blown or
washed away to new locations. Dead sea creatures float to the
bottom of the ocean or lake.
Sediments pile up and become pressed together.
The resulting weight compresses the sediments at the bottom.
Rock crystals and salts cement the sediments together, creating
sedimentary rock.
Most prevalent type of rock on Earth’s surface.
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7. Metamorphic rocks have “morphed” into another kind
of rock.
They were once igneous or sedimentary rock.
Rocks deep in the earth (7 – 9 mi) are exposed to
tremendous heat (between 400 and 1,500 degrees F)
and pressure.
Sandstone -> Quartzite
Limestone -> Marble
Shale -> Slate
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8. What is a cycle?
A model that describes the formation, breakdown and
reformation of a rock as a result of
sedimentary, igneous and metamorphic processes.
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