Geology 101
Exam #3
Spring 2001


1. Which of the following is not a type of fossil fuel?
a. coal
b. gas
c. uranium
d. lignite
e. peat


2. The term "foliation" in metamorphic rocks refers to:
a. the inclusion of fossilized plant remains in rocks
b. a quantitative measure of the degree of metamorphism
c. folding of the rock by lateral pressure
d. a consistent orientation of the mineral grains
e. the size of the lineations


3. The type of metamorphism that results entirely from the heat of magma and from hot circulating fluids is:
a. contact metamorphism
b. regional metamorphism
c. dynamothermal metamorphism
d. shock metamorphism
e. butterfly metamorphism


4. Blueschist facies rocks are formed:
a. around intruding igneous rocks such as batholiths
b. within shallower parts of subduction zones
c. under the deepest parts of subduction zones, well below the roots of mountains
d. within transform faults as a result of heat produced by friction
e. where a meteor impacts the earth


5. Which low-grade metamorphic rock, composed of extremely fine-sized mica and other mineral grains, typically exhibits well-developed rock cleavage?
a. schist
b. hornfels
c. slate
d. gneiss
e. quartzite


6. Which of the following is a primary ore of aluminum?
a. resistate
b. massive sulfide
c. kimberlite
d. bauxite
e. all of the above


7. In general, gems are
a. rare minerals
b. radioactive minerals
c. beautiful varieties of common minerals
d. not colored or dyed or altered in any way from the way they occur naturally
e. made of diamond


8. Which response has rocks in the correct order from (left to right) low-grade and fine grain size to high-grade and coarse grain size?
a. slate=>phyllite=>schist
b. phyllite=>slate=>schist
c. schist=>slate=>phyllite
d. slate=>schist=>phyllite
e. (wrong answer)


9. If a metamorphic rock contains lots of carbonate minerals, what was it before it was metamorphosed?
a. quartzite
b. shale or mudstone
c. a plutonic rock
d. limestone or dolostone
e. bauxite


10. Which of the following statements concerning diamonds is NOT true?
a. diamonds are most often found in kimberlite pipes
b. diamonds are formed as a result of extreme pressure on coal that has been buried to a depth of more than 150 kilometers (90 miles)
c. all diamonds that are no longer deep within the Earth are in the process of deteriorating into graphite
d. diamond is the world's hardest natural substance
e. diamonds are very valuable, but some are much more valuable than others


11. When we use a number to describe a mineral's hardness, we are using the _________________.
a. Mohs scale
b. Richter scale
c. Peterson tenacity test
d. Abrasion scale
e. cleavage number


12. Amethyst, opal, citrine and chalcedony are gem varieties of
a. feldspar
b. mica
c. beryl
d. quartz
e. feldspar


13. Which of the following would be considered a mineral?
a. Opal.
b. Diamond.
c. Obsidian.
d. Glass.
e. Dexyite


14. All silicate mineral have what in common?
a. they all form from magmas
b. they all contain silicon-oxygen tetrahedra
c. they all contain iron and magnesium
d. they all contain silicic acid
e. they all break down quickly at the Earth's surface


15. Which of the following is NOT a mineral?
a. quartz
b. copper
c. granite
d. calcite
e. plagioclase (feldspar)


16. What is the most abundant mineral in the Earth's crust?
a. quartz
b. copper
c. granite
d. calcite
e. plagioclase (feldspar)


17. Ruby and sapphire are gems. What mineral are they composed of?
a. quartz
b. beryl
c. corundum
d. diamond
e. amethyst


18. A silicon tetrahedron has ___ oxygen ions.
a. 1
b. 2
c. 3
d. 4
e. 5


19. Which of the following can concentrate ore minerals to make an ore body?
a. gravity
b. hydrothermal solutions
c. metamorphism
d. igneous activity
e. all of the above


20. Which of the following types of rocks can become metamorphic rocks?
a. sedimentary rocks only
b. sedimentary or igneous rocks only
c. sedimentary or metamorphic rocks only
d. sedimentary, igneous, or metamorphic rocks
e. (bluff answer)


21. Schist can be distinguished from other metamorphic rocks by:
a. its large flakes of mica
b. its dark and light mineral bands
c. its metallic sheen
d. its slaty cleavage
e. the presence of garnet, pyroxene or amphibole


22. The rock that results from the metamorphosis of relatively pure limestone is:
a. hornfels
b. quartzite
c. gneiss
d. marble
e. all of the above


23. Metamorphic rocks form through all of the following processes EXCEPT:
a. compacting under tremendous pressure
b. melting and recrystallizing
c. chemically changing under the influence of ion-containing fluids
d. chemically changing under the influence of heat
e. chemically and structurally changing as the result of a meteor impact


24. Gneiss can be distinguished from other metamorphic rocks by:
a. its heft
b. its large flakes of mica
c. its metallic sheen
d. its slaty cleavage
e. its dark and light mineral bands




25. The rock that results from the metamorphosis of relatively pure limestone is:
a. marble
b. quartzite
c. gneiss
d. basalt
e. obsidian


26. In geology, a mineral is defined as:
a. a natural substance that is neither animal nor plant, has a specific composition and structure, and contains one or more silicon-oxygen tetrahedra.
b. a solid substance or element that is essential to human nutrition.
c. a naturally occurring usually inorganic solid consisting of chemical elements in specific proportions, whose atoms are arranged in a systematic internal pattern.
d. a naturally occurring crystalline inorganic solid that contains only one element.
e. anything that occurs naturally


27. If a mineral exhibits cleavage, it:
a. breaks very easily
b. always occurs in the same shape
c. breaks consistently along distinct planes
d. fractures as a curved, shell-shaped (conchoidal) surface
e. all of the above


28. Placer deposits of metals are formed by
a. hydrothermal processes
b. secondary enrichment processes
c. igneous processes
d. sedimentary processes
e. contact metamorphic processes


29. Which of the following is true about ferromagnesian minerals:
a. they tend to have dark colors
b. they include pyroxenes and amphiboles
c. they contain iron or magnesium
d. they have higher specific gravity than quartz or feldspar
e. all of the above


30. If you found a glassy appearing mineral while rock hunting and thought it was a diamond, what simple test could you use to help you make the determination?
a. test it with hydrochloric acid
b. taste it
c. check its hardness
d. see if it burns
e. check its color


Short Answers

1. What are hydrothermal solutions?
2. What is metamorphism? What are the agents that cause metamorphism?
3. Some minerals require a very low concentration factor to make mining them economical. Others require a very high concentration factor. Why? Give examples.
4. Distinguish between contact metamorphism and regional metamorphism. Which creates the largest volumes of metamorphic rock?
5. Although all minerals have an orderly internal arrangement of atoms (crystalline structure), most mineral samples do not exhibit their crystal form. Why?
6. Briefly describe how minerals accumulate in placers. Give examples of three minerals that are mined from placers.