Question 1

What gas is a radioactive daughter product of the U- 238 decay series?

Accepted Answer

A)   xenon- 143
B)   argon- 40
C)   radon- 226
D)   carbon- 14E) All of the above
F) A) and B)

Question 2

Acritarchs, conodonts, graptolites and trilobites would all be useful as index fossils, environmental indicators, or relative dating tools for _________.

Accepted Answer

A)   Mesozoic coals
B)   Cretaceous through Eocene aeolian deposits
C)   Cenozoic conglomerates
D)   Paleozoic marine shales and carbonatesE) A) and C)
F) C) and D)

Question 3

After the normal fault A moved, which was the next younger geologic feature?

Accepted Answer

The answer of After the normal fault A moved, which...

Question 4

The Phanerozoic Eon comprises approximately the ________of geologic time.

Accepted Answer

A)   first 15%
B)   last 15%
C)   first 85%
D)   last 85%E) A) and B)
F) None of the above

Question 5

In a given area where you have little knowledge of the local geology (rocks types, fossils, etc.), what type of unconformity would be the most difficult to recognize in an exposed sequence of rocks? Why?

Accepted Answer

Disconformity. Rock layers above and bel...

Question 6

Which organisms were free swimmers and found in a great variety of Paleozoic and Mesozoic marine habitats?

Accepted Answer

A)   chitnozoans and graptolites
B)   diatoms and diatoms
C)   flatclams and trilobites
D)   ammonoids and conodontsE) A) and C)
F) A) and B)

Question 7

Complex, invertebrate, life forms are common as fossils, beginning with marine strata of Cambrian age. How long ago did the Cambrian Period begin?

Accepted Answer

A)   65 million years
B)   542 million years
C)   4.6 billion years
D)   542 billion yearsE) A) and C)
F) All of the above

Question 8

The half- life of carbon- 14 is about 5730 years. Assume that a sample of charcoal formed by burning wood that lived 15,000 years ago. How much of the original carbon- 14 would remain today?

Accepted Answer

A)   >1/2
B)   1/8 to 1/16
C)   1/2 to 1/4
D)   1/4 to 1/8E) B) and C)
F) All of the above

Question 9

_______is an erosional contact between tilted, older strata below and horizontal, younger strata above?

Accepted Answer

A)   A disconformity
B)   An angular unconformity
C)   A cross- cutting fault
D)   An angular deformityE) B) and C)
F) None of the above

Question 10

The half- life of carbon- 14 is about 5730 years. Assume that a sample of charcoal formed by burning wood that lived 25,000 years ago. How much of the original carbon- 14 would remain today?

Accepted Answer

A)   1/4 to 1/8
B)   1/2 to 1/4
C)   1/8 to 1/16
D)   1/16 to 1/32E) B) and C)
F) All of the above

Question 11

The ratio of radioactive parent to stable daughter atoms in a mineral is measured as 1:3. How many half- lives have elapsed since the mineral grain formed, assuming that only parent atoms were present when it crystallized?

Accepted Answer

A)   2.0
B)   0.5
C)   1.5
D)   3.0E) B) and C)
F) A) and D)

Question 12

Which of the following is an essential characteristic of an index fossil?

Accepted Answer

A)   The fossils occur in deep- water marine sediments, but the organism actually lived in the sunlit, surface layer of the ocean.
B)   The organism only lived for a short span of geologic time but was very widespread.
C)   The fossils are exceptionally abundant for a long time span and readily preserved.
D)   The organism lived only in specific environments such as beaches or estuaries.E) None of the above
F) A) and B)

Question 13

An unconformity is__________.

Accepted Answer

A)   an erosional (or non- depositional)  surface with younger strata above and older rocks below
B)   the contact between a cross- cutting pluton and sedimentary rocks
C)   the lower contact of an intrusive sill with sedimentary strata
D)   a fault with younger, sedimentary rocks above and older, igneous rocks belowE) None of the above
F) C) and D)

Question 14

At the end of the Cretaceous (K/T boundary)  what unusual geologic phenomenon occurred that has been linked to mass extinction and the end of the dinosaurs?

Accepted Answer

A)   A 10 km diameter meteor impact occurred on the Yucatan peninsula.
B)   The climate abruptly warmed and massive weathering of iridium poisoned the seas
C)   Enormous outpourings of basaltic lavas built the Rocky Mountains in British Columbia.
D)   Dinosaurs were hunted to extinction by Klingons.E) A) and D)
F) B) and D)

Question 15

Which of the following denotes remains of particular organisms that were widely distributed, but lived for only a relatively brief interval of geologic time?

Accepted Answer

A)   eratosthenes
B)   internal moulds
C)   fleeting impressions
D)   index fossilsE) C) and D)
F) B) and C)

Question 16

What is the source of natural carbon- 14?

Accepted Answer

A)   cosmic ray collisions triggering "neutron- capture" in ordinary atmospheric nitrogen
B)   leakage of radioactive gases from the liquid, outer core
C)   nuclear fission of the heavy, radioactive elements uranium and thorium
D)   fusion of hydrogen and helium in the Sun and eruption of solar flaresE) None of the above
F) C) and D)

Question 17

Which of the following statements is true, concerning sedimentary strata separated by a disconformity?

Accepted Answer

A)   All of the older strata were eroded away before the younger strata were tilted.
B)   All strata exhibit parallel bedding or stratification, but there is a hiatus (missing record) .
C)   The younger strata were tilted after the older strata were.
D)   The older strata were tilted when the younger strata were deposited.E) A) and D)
F) B) and C)

Question 18

How can fossiliferous sedimentary rock most easily be dated and correlated if they lack the most diagnostic index fossil for that period or epoch?

Accepted Answer

A)   by mapping out the intervening contacts or drilling a series of boreholes between
B)   by using the entire fossil assemblage and ranges for the two localities in question
C)   by performing radiometric dating like U- 238/Pb- 206 or C- 14 on fossils
D)   by paying a geologist to tell you the answerE) B) and C)
F) A) and D)

Question 19

Which of the following best characterizes an angular unconformity?

Accepted Answer

A)   The discordant boundary between older strata and an intrusive body of granite.
B)   Horizontal lava flows lie below the unconformity and horizontal, sedimentary strata lie above.
C)   Tilted strata lie below the unconformity; bedding in younger strata above is parallel to the unconformity.
D)   Igneous dykes cutting through sills at an angle.E) All of the above
F) A) and C)

Question 20

Both long- lived, naturally occurring, uranium isotopes decay through a series of intermediate, radioactive, daughter isotopes to stable isotopes of _________.

Accepted Answer

A)   lead
B)   carbon
C)   thorium
D)   radonE) A) and B)
F) A) and D)

Exam 19: Shorelines

At the end of the Cretaceous (K/T boundary) what unusual geologic phenomenon occurred that has been linked to mass extinction and the end of the dinosaurs?

Correct AnswerverifiedShow Answer

How can fossiliferous sedimentary rock most easily be dated and correlated if they lack the most diagnostic index fossil for that period or epoch?

Correct AnswerverifiedShow Answer

The ratio of radioactive parent to stable daughter atoms in a mineral is measured as 1:3. How many half- lives have elapsed since the mineral grain formed, assuming that only parent atoms were present when it crystallized?

Correct AnswerverifiedShow Answer

The half- life of carbon- 14 is about 5730 years. Assume that a sample of charcoal formed by burning wood that lived 15,000 years ago. How much of the original carbon- 14 would remain today?

Correct AnswerverifiedShow Answer

What is the source of natural carbon- 14?

Correct AnswerverifiedShow Answer

In a given area where you have little knowledge of the local geology (rocks types, fossils, etc.), what type of unconformity would be the most difficult to recognize in an exposed sequence of rocks? Why?

Correct AnswerverifiedDisconformity. Rock layers above and bel...View AnswerShow Answer

_______is an erosional contact between tilted, older strata below and horizontal, younger strata above?

Correct AnswerverifiedShow Answer

Which of the following is an essential characteristic of an index fossil?

Correct AnswerverifiedShow Answer

Acritarchs, conodonts, graptolites and trilobites would all be useful as index fossils, environmental indicators, or relative dating tools for _________.

Correct AnswerverifiedShow Answer

An unconformity is__________.

Correct AnswerverifiedShow Answer

Which of the following denotes remains of particular organisms that were widely distributed, but lived for only a relatively brief interval of geologic time?

Correct AnswerverifiedShow Answer

The Phanerozoic Eon comprises approximately the ________of geologic time.

Correct AnswerverifiedShow Answer

The half- life of carbon- 14 is about 5730 years. Assume that a sample of charcoal formed by burning wood that lived 25,000 years ago. How much of the original carbon- 14 would remain today?

Correct AnswerverifiedShow Answer

After the normal fault A moved, which was the next younger geologic feature?

Correct AnswerverifiedShow Answer

Which of the following statements is true, concerning sedimentary strata separated by a disconformity?

Correct AnswerverifiedShow Answer

Which of the following best characterizes an angular unconformity?

Correct AnswerverifiedShow Answer

Which organisms were free swimmers and found in a great variety of Paleozoic and Mesozoic marine habitats?

Correct AnswerverifiedShow Answer

Both long- lived, naturally occurring, uranium isotopes decay through a series of intermediate, radioactive, daughter isotopes to stable isotopes of _________.

Correct AnswerverifiedShow Answer

Complex, invertebrate, life forms are common as fossils, beginning with marine strata of Cambrian age. How long ago did the Cambrian Period begin?

Correct AnswerverifiedShow Answer

What gas is a radioactive daughter product of the U- 238 decay series?

Correct AnswerverifiedShow Answer

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Disconformity. Rock layers above and bel...
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