Download First Hour Exam, Fall, 2006

Geology 141
Autumn, 2006
Name
6 October, 2006
GE141: Understanding Earth
~
First Hour
Examination
INSTRUCTIONS:
PLEASE read the instructions and
questions CAREFULLY and completely.
If you do not
understand a question as it appears on the exam,
PLEASE ASK FOR CLARIFICATION!!
It is to YOUR
benefit to do so.
This examination is worth 125
points, or 12.5% of your overall semester grade.
Exams will be graded as quickly as possible; your
individual point total will be entered on the last
page to ensure that only you know how well you did
on the exam, unless you choose to divulge that
information to others.
"Patriotism at the expense of another nation is as
wicked as racism at the expense of another race....
Let us resolve to be patriots always, nationalists
never. Let us love our country, but pledge
allegiance to the earth and to the flora and fauna
and human life that it supports - one planet
indivisible, with clean air, soil and water; with
liberty, justice and peace for all."
Geology 141: Fall, 2006
First Hour Examination
William
(1924-2006), 2003
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Sloane
Coffin
Geology 141: Fall, 2006
First Hour Examination
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Section I: Multiple-choice.
Please circle the letter of the
correct or best response to each question.
Each question is
worth 3 points; the section as a whole is worth 75 points of the
125 for the exam.
1. The current estimate of the age of the Universe (from the time of the "Big Bang") is
approximately
a. 5 million years
c. 5 billion years
b. 12-15 million years
d. 12-15 billion years
2. The best estimate of the age of our Solar System and the Earth is
a. 5 million years
c. 5 billion years
b. 12-15 million years
d. 12-15 billion years
3. The elements above iron in the Periodic Table (the transferric elements) are considered
evidence that our solar system, including the Earth, are a second-generation star
system because these elements
a. must have come from outside our galaxy.
b. only form by radioactive decay deep underground.
c. are formed from cosmic rays bombarding the Earth.
d. form only in the extreme temperatures and pressures of exploding stars
(supernovas).
4. The mantle of the Earth is believed to be composed mainly of
a. silicon and oxygen
d. solid iron
b. molten iron
e. magma
c. iron and magnesium silicate minerals at the top, and oxides at the bottom
5. The continental crust of the Earth is about how thick?
a. 5-8 km
c. 100-200 km
b. 40-70 km
d. 2900 km
6. The two most abundant elements, by weight, in the Earth's crust are
a. iron and nickel
c. oxygen and silicon
b. iron and silicon
d. silicon and aluminum
7. The major mineral groups are classified according to
a. the density of the mineralsc. the crystal structure of the minerals
b. the color of the minerals d. the chemical composition of the minerals
8. The ________ comprise >50% of the Crust of the Earth.
a. oxides
c. carbonates
b. sulfides
d. feldspars
9. The only non-silicate mineral group that is more important for its abundance in the
Crust than its economic significance is the
a. oxides
c. carbonates
b. sulfides
d. feldspars
10. The ocean basins exist because of
a. constant regeneration of oceanic crust at the Mid-Oceanic Rise and Ridge
System.
b. constant subduction beneath the mid-ocean basins, as the ocean floor is
pulled down by gravity and the continents are pushed up.
c. deep holes left by meteors and other impacts in the Earth's early history.
d. convection in the upper mantle, that pulls the ocean floor down along the
Mid-Oceanic Rise and Ridge System.
Geology 141: Fall, 2006
First Hour Examination
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11. The islands of Hawai'i and the Galápagos Islands all exist because they're
a. island arc systems above subduction zones.
b. parts of the Mid-Oceanic Rise and Ridge system.
c. the isolated, weathered remnants of what was once the continent of Atlantis.
d. the tops of volcanoes created by mantle plumes beneath moving oceanic
plates.
12. What rock type would you most expect to find in a typical shield volcano, such as
Mauna Loa or Kilauea in Hawai'i ?
a. basalt
c. andesite
b. gabbro
d. granite
13. What rock type would you most expect to find in a typical stratovolcano, such as the
Soufriere Hills volcano on Montserrat, Tungurahua in Ecuador, or Mt. St. Helens in
Washington State?
a. basalt
c. andesite
b. gabbro
d. granite
14. Typical spreading rates on the Mid-Oceanic Rise and Ridge system range from
a. 5-15 mm/day
c. 5-15 mm/year
e. 5-15 km/day
b. 5-15 cm/day
d. 5-15 cm/year
f. 5-15 km/year
15. The minerals that comprise Bowen's Reaction Series are arranged, from top to bottom,
by
a. their melting temperature (highlow) and silica content (lowhigh)
b. their position in the Palisades sill - those being higher in the sill being placed
higher in the diagram.
c. age of the minerals - those at the top date from earlier in Earth's history,
while those at the bottom are forming today.
d. their chemical composition - those at the top being non-silicates, while those
at the bottom are all silicates.
16. While on vacation hiking in Wyoming, you encountered a light-colored plutonic rock
that was quite striking where it had intruded into black shales. Though you couldn't
determine whether it was a diorite or a granite, you decided to walk this contact to see
where it went. Three days later, you were back where you started. Looking at the map,
you discovered that you had walked around a total area of 67 square miles (172 km 2).
Quite pleased with yourself, you knew you'd walked the entire limits of a
a. lithosphere
c. stock
e. protolith
b. batholith
d. laccolith
f. lithograph
17. Dikes are
a. high ridges and plateaus of volcanic rock, left by erosion.
b. tabular, parallel-sided bodies of intrusive igneous rock that cut across preexisting rock structures.
c. naturally occurring ridges on the coast of the Netherlands.
d. any naturally occurring ridge on the land surface.
18. Typical island-arc systems include all of the following except
a. the Japanese archipelago
c. the Kuril Islands
b. the Aleutian Islands
d. the islands of Iceland
19. The critical difference between mechanical weathering and chemical weathering
processes is that
Geology 141: Fall, 2006
First Hour Examination
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a. mechanical weathering takes place as material is moving, while chemical
weathering takes place as it's sitting in one place.
b. mechanical weathering produces smaller fragments of the same
composition,
while chemical weathering changes the composition.
c. mechanical weathering is human-induced, but chemical weathering is
natural.
d. mechanical weathering is the same as erosion, but chemical weathering is different
from erosion because it involves chemistry.
20. Ice-wedging is a very effective mechanical weathering process because
a. water expands as it freezes, pushing rocks apart from the inside.
b. the ice grinds away at the rocks as it forms, like a tiny glacier.
c. the minerals in the rock become incredibly unstable at subfreezing
temperatures, and break down into other minerals.
d. the ice pushes tiny soil particles deep into the rock, forcing it to split.
21. The most important function of mechanical weathering is to
a. create rich, fertile soils.
b. increase the surface area exposed on rocks and minerals, where chemical
weathering can take place most effectively.
c. release metallic cations into the soil as soil nutrients
d. remove loose debris from slopes so chemical weathering can attack the
underlying rocks.
22. ALL clays are ultimately derived from
a. fine-grained sediments formed by grinding of rocks.
b. mechanical weathering of non-silicate minerals.
c. chemical combinations of phosphate and carbonate minerals.
d. chemical weathering of silicate minerals.
23. The soil horizon with the most biological activity AND the highest level of chemical
weathering processes is the
a. parent material
c. B horizon
b. A horizon
d. C horizon
24. The only nutrient that plants need to get from the soils that does NOT come from the
chemical weathering of minerals is
a. calcium
d. magnesium
b. iron
e. nitrogen
c. potassium
f. sulfur
25. Two key nutrients plants need to get from soils in order to form proteins are
a. sulfur and potassium
c. potassium and phosphorus
b. sulfur and nitrogen
d. nitrogen and iron
Geology 141: Fall, 2006
First Hour Examination
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Section II: Please respond to each question in the most appropriate
fashion.
Please make your responses concise and to the point,
but thorough; use sketch diagrams any place you believe that they
may help explain your response.
There should be ample space
provided for an adequate response to each question; PLEASE
RESTRICT YOUR RESPONSES TO THE SPACE PROVIDED. PLEASE ALSO try to
write legibly; I CANNOT give any credit for responses I can't
read!
The number of points for each question is indicated in
parentheses after the question; there are 40 points possible for
this entire section.
(And PLEASE remember as well that, as promised on the syllabus, I
WILL deduct a point each time I see "volcanoe" or "techtonic!")
26. Please fill in the names of each of the minerals in Bowen's Reaction Series, in the
appropriate spaces below (10 points: 1 point each + one bonus point for the first correct
answer).
/
/
/
/
|
|
|
27. Rocks are classified into three groups based on how they originate; what ARE the major
rock groups? What is this particular kind of classification scheme called? (5 points)
The three groups are the:
a.
c.
b.
This is called a
classification.
Geology 141: Fall, 2006
First Hour Examination
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28. What is a convergent plate margin? (3)
Describe what typically occurs at a convergent margin between an oceanic lithospheric
plate and a continental plate, including an example of a place where this process is
taking place today. (7)
A convergent plate margin is
29. Describe the formation of phenocrysts in a volcanic rock - showing that you both know
what they are and how they form; feel free to use a sketch if it will help. (10 points)
Geology 141: Fall, 2006
First Hour Examination
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30. In discussing the chemical weathering process of hydrolysis, we used an equation to
show what happens to a "generic" silicate mineral as it weathers - i.e., how a typical
silicate mineral will break down. Please fill in the blanks in the following equation with
the correct end products (5 points: 2-1-1-1)
+
Generic silicate + water (H2O) 
+
+
Section III: Geography. On the maps on the following page (the maps
are printed back-to-back), please locate precisely each of the
following localities or features.
FOR SMALL FEATURES OR
LOCALITIES, use a sharp arrow drawn from your label to the
feature, so there can be no doubt about what you are labeling.
PLEASE remember that IT IS TO YOUR BENEFIT that your label is
clear enough that there is NO question as to your meaning or
intent! (10 points, 1 point each)
And YES, all labels must be correctly spelled for credit!
[ Since all you have to do is copy the name from the list below! ]
On the map of the U.S. & Canada:
New Brunswick
Lake Ontario
Wyoming
Arizona
Chesapeake Bay
On the map of the world:
Iceland
Kamchatka
Andes Mountains
Uruguay
Japan
Grade on exam: __________________ out of 125 possible*.
* If this is below 85, please see me within the next week !!!
PLEASE NOTE: After exams are graded, I will return your exam ONLY to you. It
will not be released to friends, roommates, your lab partner, or anyone else.
This is to ensure YOUR security and confidentiality.