GEOL 101 - Introductory Geology: Exploring Planet Earth – Spring 2011
Test #2 – March 22, 2011
Name KEY
ID# KEY
Multiple choice questions (2 points each).
1. The process of compaction and cementation of sediments to form a hard sedimentary rock is:
a) diagenesis
b) lithification c) amalgamation d) solidification
2. Chemical sedimentary rocks are:
a) made of fragments of pre-existing rocks
b) larger than 2mm in grain size
c) typically cross-bedded
d) formed by precipitation of minerals out of solution
3. Clastic sediments and the rocks they produce are primarily classified according to:
a) clast (i.e. fragment) size b) where they are found
c) what minerals are present
d) the shape of the clasts
4. A mudstone would be made of:
a) silt and clay sized material
b) sand sized material
c) gravel sized material
5. Clastic sediments deposited at the base of a steep mountainside might form what rock?
a) conglomerate
b) sandstone c) siltstone d) mudstone e) breccia
6. A chemical sedimentary rock made of quartz would be called what?
a) shale
b) sandstone
c) arkose
d) limestone e) chert
7. A chemical sedimentary rock made of calcite would be called what?
a) shale
b) sandstone
c) arkose
d) limestone
e) chert
8. What size sedimentary material might you find where a river delta empties into the ocean?
a) gravel
b) sand
c) clay
9. What type of metamorphic rock is formed over large areas of the Earth’s crust and by directed pressure?
a) contact
b) regional
c) hydrothermal
10. Metamorphism which occurs around the margins of a hot igneous intrusion is called:
a) regional metamorphism
b) contact metamorphism
c) hydrothermal metamorphism
11. The lower and upper limits of metamorphic conditions are bounded by conditions of:
a) compaction and oxidation
b) lithification and partial melting
c) diagenesis and hydrolysis
12. The alignment of platy minerals like muscovite such that metamorphic rocks break into sheet-like
fragments is called:
a) gneissic banding
b) brittle deformation
c) foliation
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13. Which of the following is a common low-grade metamorphic index mineral?
a) garnet
b) amphibole
c) chlorite
d) sillimanite
14. Which of the following is a regional metamorphic rock?
a) schist
b) slate
c) gneiss
d) phyllite
e) all of these
15. When a limestone is metamorphosed a ____________ is produced.
a) slate
b) marble
c) schist
d) quartzite
16. What mineral might be a good index mineral for a high grade metamorphic rock?
a) mica
b) quartz
c) chlorite
d) sillimanite
17. When a sandstone is metamorphosed a ____________ is produced.
a) slate
b) marble
c) zeolite
d) quartzite
18. Medium grade metamorphism of a mafic igneous rock (basalt) will produce a rock called:
a) schist
b) greenschist
c) gneiss
19. The sequence of metamorphic rock types produced from a shale or mudstone when going from low to
high grade metamorphism is:
a) phyllite, slate, schist and gneiss b) slate, phyllite, gneiss and schist
c) slate, phyllite, amphibolite and gneiss
d) slate, phyllite, schist and gneiss
20. Metamorphic rocks are important because they preserve information about the conditions they formed
under. These include:
a) temperature
b) stress orientation
c) pressure
d) all of these
21. When a rock is deformed by directed pressure (differential stress) what type of texture may result?
a) coarsely crystalline b) foliation
c) non-foliated
22. What part of a streams load will be transported regardless of water velocity?
a) bed load b) suspended load c) dissolved load
23. The measure of the amount of water flowing through a river channel is what?
a) velocity
b) discharge
c) cross sectional area
24. Ions in solution (that originate from chemical weathering) in river water are called what?
a) suspended load
b) bed load
c) dissolved load
25. Given the following sedimentary material, which is most likely to be present as suspended load in a
very slow moving river such as at a delta?
a) gravel
b) sand
c) silt
d) clay
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26. A river with a very high gradient, such as a river flowing in a steep mountainous terrain, will be able to
carry what size material?
a) coarse gravel
b) sand
c) clay
d) all of these
27. The ultimate base level for all rivers on Earth is what?
a) large lakes b) the ocean
c) the largest rivers
28. Which of the following characteristics of rivers decreases going downstream?
a) sediment size
b) water velocity
c) gradient
d) all of these
29. Floodplains develop due to:
a) meandering of stream channels b) overflow of streams c) both of these
30. Most erosion in a meandering stream channel occurs where?
a) on the outside of bends b) on the inside of bends
c) between bends
31. The principle of ____________ states that sedimentary rocks lower in a sequence are older.
a) original horizontality b) superposition c) cross cutting d) inclusions e) faunal succession
32. The principle of ____________ states that objects inclosed in rock must be older than the rock.
a) original horizontality b) superposition c) cross cutting d) inclusions e) faunal succession
33. The principle of ____________ states that fossils appear in the rock record according to definite
chronological patterns, including progressively more complex fossils in younger rocks.
a) original horizontality b) superposition c) cross cutting d) inclusions e) faunal succession
34. An ______________ is an angular contact between sedimentary layers.
a) noncomformity b) disconformity c) angular uncomformity
35. A ______________ is an irregular erosional contact between sedimentary layers which are parallel.
a) noncomformity b) disconformity c) angular uncomformity
36. A ______________ is a contact between igneous/metamorphic rocks and sedimentary rocks.
a) noncomformity b) disconformity c) angular uncomformity
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Questions 37-41 refer to the following diagram:
37. What event occurred immediately after deposition of the upper section of sedimentary rocks (the
section which includes the conglomerate and shale)?
a) fault A
b) fault B
c) dike A
d) dike B e) intrusion of the batholith
38. Which of the following is the youngest event?
a) fault A
b) fault B
c) dike A
d) dike B
e) intrusion of the batholith
39. Which of the following is the oldest event?
a) fault A
b) fault B
c) dike A
d) dike B
e) intrusion of the batholith
40. If the batholith is dated and found to be 105 million years (Ma) old, then how old is dike B?
a) older than 105 Ma b) younger than 105 Ma
c) 105 Ma
41. If the batholith is 105 million years (Ma) old, and dike A is 95 Ma, then how old is dike B?
a) older than 105 Ma b) younger than 105 Ma
c) between 95 and 105 Ma
42. Which interval of geologic time is generally characterized by the appearance of abundant fossils in the
rock record?
a) Phanerozoic b) Cenozoic c) Mesozoic d) Proterozoic
43. Which interval of geologic time means “recent life” and is the era which includes the present time?
a) Phanerozoic b) Cenozoic c) Mesozoic d) Proterozoic
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44. Which interval of geologic time contains approximately 88% of Earth’s history?
a) Cenozoic b) Mesozoic c) Paleozoic d) Precambrian
45. Using radioactive elements to determine absolute age of rocks and minerals relies on knowledge of the
half life of the unstable radioactive parent isotope. After one half-life the ratio of daughter to parent
(daughter/parent) will be:
a) 1/3
b) 1/2
c) 1
d) 2
e) 3
46. After 2 half-lives have passed what would the ratio of daughter to parent (daughter/parent) be?
a) 1/3
b) 1/2
c) 1
d) 2
e) 3
47. Approximately what percentage of water on Earth is fresh water (not in the oceans)?
a) 78% b) 30% c) 11% d) 3%
48. Approximately 85% of the fresh water on the Earth is present as:
a) groundwater b) surface water c) glacial ice d) water vapor in the air
49. After approximately how many half-lives is a radioactive dating system considered to be no longer
useful?
a) 1 b) 2 c) 4 d) 7
50. What is the currently accepted age of the Earth?
a) 6,000 years b) 20 million years c) 1 billion years
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d) 4.5 billion years