Department
of Earth Science |
Northeastern
Illinois University
INTRODUCTION TO EARTH SCIENCE
ESCI 121
Section 05
Fall 2008
Department
of Earth Science |Northeastern
Illinois University
w Answer these quick assessment questions about sedimentary rocks:
| 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.
w 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
w 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
w Describe these
non-foliated rocks, and tell what their protoliths are:
marble quartzite anthracite
w
Examine, describe,
classify, and name the metamorphic rocks in your rock kit: #101, 107, 109, 115,
116, 131, 140, 147.
w 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)
w
For the minerals listed
above, find examples of them in your mineral kit.
IGNEOUS
ROCKS
w
Examine the igneous rocks
in the rock box. Classify and describe them based on their composition and
texture. Show that you can describe the following rocks:
basalt
andesite rhyolite
gabbro diorite granite
obsidian pumice scoria
THE ROCK CYCLE
w
Put it all together!
Using rock samples and chalk, create a concept map that demonstrates your
understanding of the processes involved in the rock cycle.
REVISITING "ROCK YOUR STATE!"
w
One month ago, as part of the "Rock Your State!"
assignment, you worked with others to create a poster illustrating the various
kinds of rocks, their important characteristics, and different ways of
classifying them. Today, revisit that poster with your group, and
fine-tune it. How much have you learned since that day?
REVISITING "GEOTECTONICS"
w
Several weeks ago, we examined fourteen different
places on Earth, studied their geologic characteristics,
and tried to discern patterns that gave clues to their geotectonic setting.
Now that you know much more about geotectonics, revisit those locations and see
how much more sense the patterns make. This will launch us into our next
topic--volcanoes!