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Rocks
Notes & Focus Questions
Directions: Get a copy of the Heath Earth
Science book and read pages 63 67, 69 71, and 76 79. If you dont do
the readings, the notes and questions will be much more difficult, so
dont skip the readings.
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Igneous Rocks form from cooled
off molten rock, either magma (underground) or
lava (at the surface.) The deeper the magma is when it
cools off, the more slowly it cools, and the larger the
crystals that form. Igneous rocks are classified according
to their mineral composition (which we generally use color
to give us clues about), whether they are dark colored (mafic),
medium colored, or light colored (felsic), and their
texture, or crystal size, whether they have large crystals,
medium sized crystals, small crystals, or amorphous rocks,
with no crystals. They may even be porphyritic rocks, with
two or more sizes of crystals.
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Sedimentary Rocks are
classified by the method they were formed. They are either
clastics, formed from sediments (bits and pieces of
pre-existing rocks), or formed by chemical means, when
insoluble substances precipitate (settle) out of mixtures of
solutions, that later evaporate, or by organic means, from
the remains of plants and animals.
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Metamorphic Rocks are changed by combinations of heat and
pressure, and are classified by the presence of
recrystallization (small crystals become larger) and
foliation (the crystals line up in layers or stripes.)
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| Do these Focus Questions
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Questions |
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68 |
#3 7 |
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74 |
#9 |
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79 |
#20 21 and 23 |
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