1. The classification of a rock is based on
a. composition
b. texture
c. mode of origin
d. color
2. The name of a rock (rock nomenclature), regardless of class, is based entirely on which two features?
a. color and grain size
b. composition and texture
c. composition and weight
d. density and grain shape
Base your answers to questions 3 through 5 on the following information as well as your knowledge of petrology.
I am an igneous rock which possess visible crystals, 15% of whichare dark colored.3. In terms of my overall composition and density, I am
a. felsic and low density
b. mafic and low density
c. felsic and high density
d. mafic and high density
4. Where and at what rate did I most likely crystallize?
a. in a volcano, slowly
b. in the mantle, slowly
c. on the ocean floor, quickly
d. deep within continental crust, slowly
5. Which is my most likely identity?
a. gabbro
b. basalt
c. granite
d. peridotite
6. Peridotite is an igneous rock which possesses a color index of (in %)
a. 0-20
b. 20-40
c. 40-60
d. 60-90
7. The name given an igneous rock texture which consists of large crystals embedded in a fine-grained matrix is
a. porphyritic
b. phaneritic
c. aphanitic
d. plutonic
8. Which is the best explanation for the formation of obsidian (volcanic glass)?
a. slow cooling which leads to the formation of invisible crystals
b. instantaneous cooling leading to no crystal formation
c. slow cooling leading to no crystal formation
d. it possesses a very high color index
9. The class of sedimentary rocks which consists of fragments of pre-existing rock material that have been cemented together is
a. crystalline
b. organic
c. felsic
d. clastic
10. Which of the following minerals are the most common form of cement joining clastic sediments together in a sedimentary rock?
a. feldspar-biotite-pyrite
b. halite-gypsum-talc
c. quartz-calcite-hematite
d. fluorite-apatite-feldspar
11. Which of the following minerals will be scratched by calcite?
a. quartz
b. feldspar
c. fluorite
d. none of the above
12. The textural and mineralogical changes which accompany a change in the pressure and temperature conditions in which a rock was originally formed is collectively referred to as
a. melting
b. lithification
c. metamorphism
d. burial
13. In which environment would we not expect metamorphism and metamorphic rock formation to be occurring?
a. 5 km below the Earth's surface
b. at the bottom of a lake
c. 5 km above the base of the crust
d. at the base of a lava flow
14. The percent of sedimentary rocks in the Earth's crust on the basis of volume is most nearly
a. 80%
b. 50%
c. 35%
d. 5 %
15. The parent rock from which a metamorphic rock was created is called the
a. protolith
b. parent
c. child
d. grain
16. Which three minerals comprise the majority of crustal rocks, regardless of class?
a. quartz-feldspar-mica
b. diamond-mica-hematite
c. hematite-magnetite-fluorite
d. quartz-gypsum-talc
17. The igneous environment which occurs at shallow crustal depths is called
a. volcanic
b. plutonic
c. phaneritic
d. hypabyssal
18. The surface environments one encounters as one travels from dry land to the ocean are
a. marine-terrestrial-estuarine
b. terrestrial-estuarine-marine
c. terrestrial-marine-estuarine
d. none of the above
19. What is the name applied to rock that is transitional between an igneous rock and a metamorphic rock, which usually shows evidence of partial melting and flow?
a. peridotite
b. migmatite
c. phyllite
d. gneiss
20. The banding (or parallel mineral layering) observed in most metamorphic rocks is referred to as foliation. Which is the most likely cause of this textural phenomenon?
a. The pressure (or stress) of burial.
b. The heating of minerals during burial.
c. The deposition of minerals into layers.
d. None of the above.
Extra Credit
Which is the expected sequence of metamorphic rock formation as a shale is progressively buried deeper into the Earth's crust?
a. slate-schist-phyllite-gneiss
b. slate-phyllite-schist-gneiss
c. talc-gypsum-calcite-fluorite
d. gneiss-schist-phyllite-slate
