Geology Test 4

1) ________ is not part of the hydrologic cycle.

C) Calcium carbonate dissolving in soil water and groundwater

2) Which one of the following statements is correct?

D) sea level drops when water is stored in expanding ice sheets and continental glaciers

3) Which of the following is the correct definition of stream gradient?

C) the drop in elevation of a stream divided by the distance the water travels

4) A natural, meandering, river channel is modified into a more or less straight and smooth,
canal-like channel. Which of the following statements is correct?

A) the natural channel had a lower gradient and higher friction than the straight channel

5) How does urbanization (paving, etc.) affect runoff and infiltration in a small, previously forested,
drainage basin?

A) infiltration decreases; runoff increases

6) Which of the following must result in a lower base level for rivers and streams?

C) sea level falls; land rises

7) ________ make up the suspended loads of most rivers and streams

C) Silt and clay-sized, detrital grains

8) ________ describes the total sediment load transported by a stream.

B) Capacity

9) At the head of a delta, the major channel splits into smaller channels that follow different paths to
the sea. These smaller channels are known as ________.

C) distributaries

10) Why is a bird-foot delta like that of the present-day Mississippi below New Orleans likely to
change naturally toward one with the shape of an equilateral triangle like the upper-case, Greek
letter delta (∆)?

B) potential, new, major distributary channels have steeper gradients than existing channels

11) In the absence of cutoff, how does a river meander loop behave over time?

D) the gradient is lowered as the channel lengthens and migrates toward the cut or outer bank of the loop

12) A ________ stream pattern is developed only on growing mountains like volcanoes or where the
land surface is tectonically doming upward.

A) radial

13) A ________ stream pattern develops on lands underlain by tilted or folded, alternating hard and
soft, sedimentary strata.

C) trellis

14) ________ is an abandoned, cutoff, meander loop.

C) An oxbow

15) ________ are characteristics of downcutting streams and a youthful stage of valley evolution.

B) Rapids and lots of whitewater

16) Many larger rivers in the Colorado Plateau region meander in deep, narrow canyons and have no
floodplains. How could this happen?

B) original, old age streams downcut as the land gradually rose

17) A water gap is ________.

D) a short segment of canyon formed where a river flows across the outcrop area of a resistant, ridge-forming rock layer

18) Which of the following is the only correct response concerning the location and causes of the
extraordinarily severe, 1993, flooding on the Mississippi River and tributaries?

C) upper basin; very heavy, sustained rainfall in the late spring and early summer

19) Which one of the following statements correctly describes how stream terraces can form?

C) a temporary base level is eliminated; the stream downcuts upstream from the old temporary base level, and the former floodplain is left well above the present elevation of the stream

20) ________ are components of the hydrologic cycle that release water vapor directly to the
atmosphere

B) Evaporation and transpiration

21) What is the drop in water surface elevation divided by the distance the water flows?

B) stream gradient

22) The ________ river has the largest discharge of any in the world

A. Amazon

23) Which one of the following does not apply to stream turbulence and average velocity?

D) laminar flow; dissolved load

24) Which one of the following is true concerning a major river system?

A) upstream tributaries generally have higher competencies than the major river

25) ________ generally constitutes the highest percentage of the annual sediment load moved by a
stream.

A) Suspended load

26) Where is erosion concentrated along a meandering stream?

D) on the outer parts of the meander loops or bends

27) Which one of the following would cause stream rejuvenation?

B) the land is uplifted

28) Which one of the following statements is true concerning natural levees?

A) mostly fine sand and silt that build up during floods

29) In a ________ drainage pattern that is generally developed in areas underlain by tilted or folded
strata, tributary streams flow along outcrop areas of the softer strata

D) trellis

30) A ________ drainage pattern is common in the Appalachian Valley and Ridge Province

C) trellis

31) A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean?
What is the average gradient?

C) 0.5m/km

32) ________ in a delta are essentially cross strata inclined toward deeper water.

A) Foreset beds

33) The ________ describes the movement of water through Earth’s hydrosphere.

A) hydrologic cycle

34) ________ describes the particle transport mode in streams intermediate between suspension and
rolling along the bottom?

D) Saltation

35) Which of the following features characterize wide streams and valleys?

A) natural levees; broad floodplains

36) Entrenched meanders are evidence for what sequence of geologic events?

C) land uplift was followed by stream downcutting

37) Which one of the following best describes how urbanization affects small-stream watersheds?

B) infiltration decreases; lag time between storms and peak runoff is shortened

38) A dam and reservoir are constructed on a graded river. What will happen?

D) deposition upstream from the dam; channel downcutting below

39) Which of the following forms at the highest grade of regional metamorphism?

D) schist

40) What platy, parallel, mineral grains are the most visual aspect of foliated metamorphic rocks?

B) micas

41) What major change occurs during metamorphism of limestone to marble?

D) calcite grains grow larger and increase in size

42) Which low-grade metamorphic rock, composed of extremely fine-sized mica and other mineral
grains, typically exhibits well-developed rock cleavage?

C) slate

43) forms by contact metamorphism of mudstones and shales

a. hornfels

44) foliated, fine-grained metamorphic rock formed from mudstone and shale

d. phyllite

45) nonfoliated metamorphic rock consisting mostly of calcite

b. marble

46) coarse-grained, metamorphic rock with alternating bands or stringers of light and dark
minerals

c. gneiss

47) ________ is thought to form by partial melting and in situ crystallization of the melted portion.

D) Migmatite

48) Tektites originate in what metamorphic environment?

B) high temperatures associated with meteorite impacts

49) Which one of the following is not likely to be genetically associated with impact of an asteroid or
large meteorite?

D) blueschists

50) Which of the following statements concerning slate is not true?

B) has abundant, coarse-grained mica

51) ________ is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a
metamorphic rock.

D) Foliation

52) ________ is a nonfoliated rock formed by contact metamorphism of a shale or mudstone.

C) Hornfels

53) Which of the following would exhibit sheared and mechanically fragmented rocks?

B) fault movements at shallow depths

54) Which of the following best describes the conditions of contact metamorphism?

C) pressures are fairly low, the rock is in the upper part of the crust, and heat is supplied from a nearby magma body

55) ________ forms from the metamorphism of limestone or dolostone

A) Marble

56) What foliated, metamorphic rock is texturally intermediate between slate and schist?

D) phyllite

57) ________ is characterized by the segregation of light- and dark-colored minerals into thin layers or
bands

A) Granitic gneiss

58) What type of foliation results from the parallel alignment of abundant, coarse-grained, mica flakes
in a metamorphic rock?

D) schistosity

59) Which of the following metamorphic rocks could be used to neutralize acidic mine waters?

A) marble

60) Which of the following lists the rocks in the order of increasing grain size and increasing grade of
metamorphism?

D) slate, phyllite, schist

61) ________ is typically formed by metamorphism of a sandstone.

B) Quartzite

62) Which of the following rocks would exhibit visible, textural evidence of having undergone some
partial melting?

B) migmatite

63) What is the major source of heat for contact metamorphism?

B) heat from a nearby magma body

64) In which setting would regional metamorphism be most likely?

B) at great depths in the crust where two continents are colliding

65) Graphite is identified in a particular schist. Which one of the following conclusions is justified?

A) the pre-metamorphic rock was a shale or mudstone containing organic matter

66) Amphibolite is a foliated metamorphic rock composed principally of hornblende and plagioclase.
How does it form?

C) by regional metamorphism of volcanic rocks such as andesite and basalt

67) What term describes the zone of contact metamorphism surrounding an intrusive magma body?

B) aureole

68) During metamorphism, what is the major effect of chemically active fluids?

A) aid in the movement of dissolved silicate constituents and facilitate growth of the mineral grains

69) What two, metamorphic rocks are composed predominantly of single minerals?

C) marble and quartzite

70) A ________ forms at very high pressures but moderately low temperatures associated with
subduction of oceanic crust and sediments.

A) blueschist

71) The elastic rebound theory for the origin of earthquakes was first proposed by ________ following
the ________ earthquake.

D) Reid; 1906, San Francisco

72) When an earthquake occurs, energy radiates in all directions from its source. The source is also
referred to as the ________.

A) focus

73) Which one of the following statements is correct?

D) S waves travel through solids and P waves travel through liquids.

74) ________ have the highest velocities

C. Primary Waves

75) Which one of the following is true regarding tsunamis?

B) They occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only a few feet.

76) The amount of destruction caused by earthquake vibrations is affected by ________.

D) all of these

77) On a typical seismogram, ________ will show the highest amplitudes.

D) surface waves

78) Major earthquakes are often followed by somewhat smaller events known as ________.

C. aftershocks

79) The ________ magnitude scale is a measure of the energy released. It does not directly measure the
extent of building damage

B) Richter

80) The instrument that records earthquake events is termed a ________.

B) seismograph

81) ________ is the maximum possible damage designation on the Mercalli scale.

A) XII

82) The position on Earth’s surface directly above the earthquake source is called the ________.

A. epicenter

83) The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.

C) elastic rebound

84) Overall, this type of seismic wave is the most destructive.

D) surface wave

85) Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in
one with magnitude 5.5?

A) 30 times

86) P waves ________.

D) are faster than S waves and surface waves

87) The Mercalli Scale is a scale from ________.

D) I to XII that rates the structural damage due to an earthquake

88) The distance between a seismological recording station and the earthquake source is determined
from the ________.

A) arrival times of P and S waves

89) The Richter magnitude of an earthquake is determined from the ________.

C) arrival time of P and S waves

90) Which one of the following best characterizes tsunamis?

D) They have relatively small amplitudes compared to their very long wavelengths.

91) The ________ earthquake was accompanied by extensive fire damage

C) San Francisco, 1906

92) ________ refers to the tendency for a foundation material to lose its internal cohesion and fail
mechanically during earthquake shaking

A) Liquefaction

93) The record of an earthquake obtained from a seismic instrument is a(n) ________.

C) seismogram

94) Most of our knowledge about Earth’s interior comes from ________.

B) seismic waves

95) Which one of the following statements about the crust is NOT true?

C) Oceanic crust is enriched in potassium, sodium, and silicon.

96) The dense core of Earth is thought to consist predominantly of ________.

A) iron

97) The lithosphere is defined as ________.

C) a rigid layer of crustal and mantle material

98) The average composition of the oceanic crust is thought to approximate that of ________.

D) basalt

99) The average composition of the continental crust most closely approximates that of ________.

B) granite

100) The Earth’s magnetic field originates by ________.

C) weak electrical currents associated with fluid motions in the outer core

101) The asthenosphere is located ________.

B) in the upper mantle