Geology 101
Exam #1
Fall 2001

1. "Fossil organisms succeed one another in a definite and determinable order, and therefore any time period can be recognized by its fossil content."
a. principle of fossil succession
b. principle of superposition
c. principle of crosscutting relationships
d. principle of original horizontality
e. principle of inclusions

2. In general, chemical weathering would occur most rapidly in a:
a. cool, moist climate
b. cool, dry climate
c. warm, moist climate
d. warm, dry climate
e. area with lots of freezing days

3. When you observe an outcrop of steeply inclined sedimentary layers, what principle allows you to assume that the beds were tilted after they were deposited?
a. principle of fossil succession
b. principle of superposition
c. principle of crosscutting relationships
d. principle of original horizontality
e. principle of inclusions

4. The Earth is about ____ years old?
a. 4.6 thousand
b. 4.6 million
c. 4.6 billion
d. 4.6 trillion
e. 4.6 gazillion

5. In general, rocks exposed in the cores of mountain ranges are ________ when compared to surrounding rocks.
a. quite old b. quite young

6. Lakes, rain, oceans, rivers and the like are all considered to be part of Earth's
a. lithosphere b. hydrosphere c. biosphere d. cryosphere e. atmosphere

7. In the rock cycle, the process that changes igneous rock into sedimentary rock involves:
a. melting, solidification and sedimentation
b. heat and pressure induced changes
c. cooling and crystallization
d. melting, metamorphism and lithification
e. weathering, transportation and deposition

8. The three principle chemical layers (layers defined on the basis of their chemical composition) of the Earth are
a. crust, asthenosphere, upper mantle
b. ocean, crust, mantle
c. moon, sun, planet
d. core, mantle, crust
e. lithosphere, asthenopshere, mesosphere

9. The three outermost layers of the Earth defined by their physical properties are
a. crust, asthenosphere, upper mantle
b. ocean, crust, mantle
c. moon, sun, planet
d. core, mantle, crust
e. lithosphere, asthenopshere, mesosphere

10. The theory of plate tectonics was mostly developed and confirmed
a. in the 18th century
b. in the 19th century
c. early in the 20th century
d. since about 1960
e. in the 21st century

11. Which of the following is the least stable due to weathering at the Earth's surface?
a. quartz
b. clay
c. olivine or pyroxene
d. water
e. calcite

12. The most common mineral group, the silicates, breaks down (due to weathering) by a process called
a. mechanical weathering
b. solifluction
c. hallucination
d. hydrolysis
e. oxidation

13. Unloading, thermal expansion, plants and critters, ice wedging and gravity can all cause
a. mechanical weathering
b. solifluction
c. hallucination
d. hydrolysis
e. oxidation

14. The most important thing that determines the type of soil that will develop in an area is
a. time b. the parent material c. climate d. freezing e. slope

15. In a typical soil profile, the topmost layer is the ______ horizon.
a. A
b. B
c. D
d. E
e. O

16. The soil of the northern great plains is a very fine soil for agriculture. What type of soil is it?
a. laterite
b. mollisol
c. tundra
d. spodisol
e. aridosol

17. Which type of rock is most likely to contain fossils?
a. igneous rocks
b. metamorphic rocks
c. sedimentary rocks
d. sandstone
e. all of the above

18. Leaching is very important to soil formation because it
a. removes salts and other unwanted things from upper soil horizons
b. stops erosion from occurring
c. ensures adequate nutrients remain
d. may prevent laterites from forming
e. all of the above.

19. Missing rock, or "a surface that represents a break in the rock record caused by erosion or non-deposition."
a. unconformity
b. cross bedding
c. continental gap
d. epoch
e. epic

20. Rocks in the lowest parts of the Grand Canyon are old. How old?
a. Permian
b. Cretaceous and Tertiary
c. Cambrian
d. Precambrian
e. Phanerozoic

21. Most of the bedrock in North Dakota is of __________ in age.
a. Permian
b. Cretaceous and Tertiary
c. Cambrian
d. Precambrian
e. Phanerozoic

22. Mechanical weathering can:
a. change the internal composition of minerals.
b. transport rock and mineral fragments to different locations
c. convert particular minerals into more stable forms
d. change the size and shape of rock structures
e. cause small rock fragments to combine to form larger rocks

23. Fossils that are most useful as time indicators are called
a. index fossils
b. time fossils
c. indicator fossils
d. extinct fossils
e. correlative fossils

24. The half life of uranium-238 is 4.5 billion years. This means that if we start with 100 atoms of uranium-238, we will have ___ atoms left after 9 billion years (two half lives):
a. 100
b. 75
c. 50
d. 25
e. 0

25. What may account for the fact that we don't have a detailed time scale for the Precambrian?
a. Precambrian rocks are not found at the surface in most parts of the Earth
b. there are not many fossils associated with Precambrian rocks
c. many Precambrian rocks were affected by metamorphism
d. we just don't know lots of things about rocks that old
e. all of the above

26. The reason that rocks or even footprints on the Moon do not weather is that:
a. the Moon has no atmosphere, and therefore no chemical weathering can occur
b. the temperatures on the Moon are so hot that all water is evaporated
c. the temperatures on the Moon are so cold that all water at the surface exists only as ice
d. the Moon's atmosphere is made exclusively of CO2 and is completely lacking in water
e. the Moon has no gravity

27. What type of soil is associated with tropical rain forests. This type of soil is associated with luxuriant natural vegetation. Is it also excellent for growing crops?
a. pedocal; no
b. pedalfer; no
c. pedalfer; yes
d. laterite; yes
e. laterite; no

28. Heat speeds up chemical reactions. So, why does chemical weathering occur slowly in deserts?
a. too much sand
b. too much sun
c. too little water
d. to hot
e. the nights are cold

29. What is the primary difference between weathering and erosion?
a. Weathering is the breaking down of rocks by mechanical means; erosion occurs by chemical means.
b. Weathering is the breaking down of minerals; erosion is the breaking down of rocks.
c. Weathering is the breaking down of rocks; erosion is the transportation of rock fragments.
d. Weathering and erosion are synonymous and may be used interchangeably.
e. Weathering always involves acids, erosion rarely does.

30. In north America, the greater portion of the central part of the United States is
a. the Precambrian Shield
b. the Appalachian Mountains
c. the Rocky Mountains
d. the Colorado Plateau
e. the North American Platform

31. When scientists are developing an explanation for something, which comes first:
a. hypothesis b. theory

32. Which of the following types of plate boundaries is Mt. St. Helens (and the rest of the Cascade Mountains) associated with?
a. subduction zone
b. seafloor spreading
c. transform fault
d. island arc
e. continental rift

33. Using certain characteristics to arrange rock units or geologic events in chronological order is called:
a. age dating
b. absolute dating
c. relative dating
d. geometric dating
e. the principle of original horizontality

34. The most abundant types of sedimentary rock are:
a. sandstones
b. limestones
c. mudstones
d. conglomerates and breccias
e. granites

35. Which of the following is, according to your book, "the most abundant chemical sedimentary rock?"
a. sandstone
b. evaporite
c. limestone
d. coquina
e. all of the above

Longer answer - answer one of these two questions in the space below and continue on the back of the page:

1. The centers of most continents contain "shields" where very old igneous and metamorphic rocks are exposed in flat lying areas. In north America, for example, we have the Precambrian shield. Yet, in general we find that old rocks are exposed in the centers of mountainous areas. So, why are very old rocks exposed in shields? What are shields and how did they form?

2. Soil types are unevenly distributed in the United States. Where are the best soils for agriculture located? Why are different types of soils found in different places (i.e., what caused the uneven distribution)? In the U.S., why are the "good" soils found where they are?