Department
of Earth Science |
Northeastern
Illinois University
INTRODUCTION TO EARTH SCIENCE
ESCI 121
Section 05
Fall 2008
Department
of Earth Science |Northeastern
Illinois University
| Answer #1 first, and then choose one other question to answer. | 1) Where on Earth (i.e. in
what environment) do most sedimentary rocks form? Explain why. 2) Imagine you find a sedimentary rock and, testing it with acid, you quickly determine that most of it is composed of calcite. What type of rock is it? In what type of environment did it probably form? 3) Imagine you find a sedimentary rock and look at it closely with a hand lens. You see it is mainly composed of sand-sized grains of quartz, but still, you test it with acid and detect fizzing. What type of rock is it? Explain why it fizzes even though it is mostly made of quartz. 4) Imagine you find two clastic (detrital) sedimentary rocks and make observations about the size of grains in the two rocks. In one, the grains are larger than 2 mm in diameter. In the other, the grains are so small you can't pick out a single, individual grain. What type of rocks are they? Explain what the difference in grain size tells you about the difference in how they were formed. |
METAMORPHIC ROCKS
w
Describe the plate tectonic settings in which
metamorphic rocks form.
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Describe, give examples of, and explain the importance
of each of the following processes and/or terms regarding metamorphic rocks:
foliation
protolith regional
metamorphism
recrystallization parent
rock contact metamorphism
color-banding
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Describe these foliated rocks, tell what their
protoliths are, and explain where each one falls on a continuum of increasing
"grade" (degree) of metamorphism:
slate
phyllite schist
gneiss
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Describe these non-foliated rocks, and tell what their
protoliths are:
marble
quartzite anthracite
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Examine, describe,
classify, and name the metamorphic rocks in your rock kit: #101, 107, 109, 115,
116, 131, 140, 147.
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Metamorphic Rock-Forming Minerals:
Using this list of common
metamorphic rock-forming minerals, tell how each is likely
to play a part in forming a metamorphic rock.
u calcite
u quartz
u
feldspar (both plagioclase and potassium feldspar--also called orthoclase)
u
clays (we do not have this in our kit boxes)
u
the mica minerals: for example, biotite and muscovite
u
the ferromagnesian minerals: for example, amphibole (also called hornblende)
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For the minerals
listed above, find examples of them in your mineral kit.