Deck 19: Shorelines

Question 1

Which type of microfossils have a tooth- like shape made of apatite, are a mouth part of an extinct swimming eel- like chordate, and are useful index fossils for the Paleozoic through Triassic?

A) conodonts
B) acritarchs and dinoflagellates
C) diatoms and radiolaria
D) coccoliths and formaminifera

Answer 1

A

Question 2

The is the idea or concept that ancient life forms succeeded each other in a definite, evolutionary pattern and that the contained assemblage of fossils can uniquely determine geologic ages of strata.

A) law of fossil regression
B) law of correlative indexing
C) principle of cross correlation
D) principle of fossil succession

Answer 2

D

Question 3

The rare element iridium has been implicated in which "ancient health" crisis?

A) poisoning of primitive algae in the Hadean Eon
B) disappearance of Neanderthal man during the early Cenozoic Era
C) extinction of the woolly mammoths in late Pleistocene time
D) extinction of the dinosaurs at the end of the Cretaceous Period

Answer 3

D

Question 4

Which of the following best characterizes an angular unconformity?

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.

Question 5

Which of the following is the name of an eon in the geologic time scale?

A) Cretaceous
B) Paleozoic
C) Phanerozoic
D) Tyson
E) Eocene

Question 6

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

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.

Question 7

The Phanerozoic Eon comprises approximately the of geologic time.

A) first 15%
B) last 15%
C) first 85%
D) last 85%

Question 8

What is the age of the Earth accepted by most scientists today?

A) 4.6 billion years
B) about 4600 thousand years
C) 4.6 million years
D) 540 billion years

Question 9

In radiometric dating, an unstable radioactive isotope is called .

A) a tachyon
B) an alpha particle
C) the parent
D) a red hot mama

Question 10

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

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

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?

A) 2.0
B) 0.5
C) 1.5
D) 3.0

Question 12

Of an original amount of radioactive parent isotope, 25% remains and 75% has decayed. How many half- lives have elapsed?

A) 2.0
B) 0.5
C) 3.0
D) 1.5

Question 13

Which of the following denotes the investigative process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas?

A) strata typing
B) correlation
C) cross- cutting
D) radioactive intuition

Question 14

Visualize (or draw) five, horizontal, sedimentary strata as exposed in a cliff or canyon wall identified by consecutive numbers, 1 being the lowest bed and 5 being the highest. Which of the following statements concerning the strata are true?

A) bed 3 is older than beds 2 and 4
B) bed 4 is older than bed 2
C) bed 5 is the oldest
D) beds 1 and 3 are older than bed 4

Question 15

Which of the following does not have at least one, very long- lived, natural, radioactive isotope?

A) Ca; calcium
B) Rb; rubidium
C) K, potassium
D) Th; thorium

Question 16

Assume that human recorded history can be stretched back to 4600 years before the present. This is approximately what fraction of geologic time?

A) one millionth
B) one billionth
C) one hundred- thousandth
D) one ten- thousandth

Question 17

Working on fossiliferous strata in the mountains of western Italy, was first to work out

A) Charles Lyell, the sequence of orogenies
B) James Hutton, the principle of uniformitarianism
C) Nicolaus Steno, the law of superposition
D) William Smith, the principle of fossil succession

Question 18

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?

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.

Question 19

A few rare times in earth history the majority of life forms disappeared "clearing the ecologic slate" for new ones. When this happens it is called .

A) an iridium anomaly
B) a mass extinction
C) an ecoshift
D) a half life

Question 20

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?

A) 1/4 to 1/8
B) 1/2 to 1/4
C) 1/8 to 1/16
D) 1/16 to 1/32

Question 21

Which English engineer and amateur geologist (his first name was William) is generally credited with first demonstrating the principle of faunal succession from his observations in building canals?

A) Smith
B) Blake
C) Wordsworth
D) Tell

Question 22

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

A) lead
B) carbon
C) thorium
D) radon

Question 23

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?

A) >1/2
B) 1/8 to 1/16
C) 1/2 to 1/4
D) 1/4 to 1/8

Question 24

Which organisms were benthic (bottom dwellers) and extensively used as index fossils respectively for the Mesozoic and Lower Paleozoic?

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

Question 25

Which type of microfossils have tests (hard parts) made of calcium carbonate and are useful as index fossils as well as for measuring past sea temperatures and climates since the Cretaceous?

A) coccoliths and formaminifera
B) diatoms and radiolaria
C) conodonts
D) acritarchs and dinoflagellates

Question 26

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

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.

Question 27

Which type of microfossils are organic walled cysts of planktonic algae primarily used in relative dating?

A) acritarchs and dinoflagellates
B) coccoliths and formaminifera
C) diatoms and radiolaria
D) conodonts

Question 28

Which of the following geologic observations would not bear directly on working out the sequence of geologic events in an area?

A) a well- exposed dyke of basalt intruding a sandstone
B) inclusions of sandstone in a granite pluton
C) the feldspar and quartz contents of a granite
D) an nonconformity between a granite and sandstone

Question 29

Why is the major branch of the K- 40 decay to Ca- 40 not useful in most cases for whole rock dating?

A) It only works 89% of the time.
B) Ca- 40 is itself unstable and further decays to more daughter products.
C) The Ca- 40 that is produced by decay is indistinguishable from the naturally most abundant isotope of Ca that may have been present initially.
D) The decay to Ar- 40 is faster and has wider geologic applicability.

Question 30

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

A) eratosthenes
B) internal moulds
C) fleeting impressions
D) index fossils

Question 31

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

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 answer

Question 32

Who made the first clear statement of the law of superposition? When?

A) Nicolaus Steno, 17th century
B) George Dawson, 19th century
C) Charles Edward Stuart, 17th century
D) William Smith, 18th century

Question 33

Sandstone strata and a mass of granite are observed to be in contact. Which of the following statements concerning their relative age is geologically correct ?

A) The sandstone is younger if the granite contains sandstone inclusions.
B) They were both formed at 4004 B.C. but the Devil made them complicated to fool us.
C) The granite is older if the sandstone contains pebbles of the granite.
D) The sandstone is younger if it shows evidence of contact metamorphism.

Question 34

Pieces of one rock contained within another are called and give evidence that that smaller rock is the main body.

A) coprolites, rejects from
B) surprises, more valuable than
C) xenoliths, younger than
D) inclusions, older than

Question 35

The ratio of parent to daughter isotopes in a radioactive decay process is 0.40. How many half- lives have elapsed since the material was 100% parent atoms?

A) <1
B) >3
C) 2- 3
D) 1- 2

Question 36

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

A) A disconformity
B) An angular unconformity
C) A cross- cutting fault
D) An angular deformity

Question 37

Which of the following denotes the divisions of the geologic time scale in correct order of decreasing lengths of time, beginning with the longest time interval and ending with the shortest?

A) eon, era, epoch, period
B) eon, epoch, period, era
C) eon, era, period, epoch
D) era, period, epoch, eon

Question 38

What kind of materials can be reliably dated by the C- 14 method?

A) biotite, hornblende, and muscovite; particularly in Mesozoic and older rocks
B) Paleozoic oil and gas deposits in limestones
C) Recent: clams, foraminifera, and wood <70,000 years old
D) Precambrian zircons in igneous and metamorphic rocks

Question 39

What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it?

A) law of original correlation
B) theory of superstition
C) law of superposition
D) theory of correlative supposition

Question 40

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

A) 65 million years
B) 542 million years
C) 4.6 billion years
D) 542 billion years

Question 41

The name of which geologic era means "ancient life"?

A) Paleozoic
B) Phanerozoic
C) Proterozic
D) "Geezer- cene"

Question 42

Why are the successive periods and epochs of the geologic time scale of unequal lengths?

A) The periods and epochs are based on the duration of unique environments like basins, or events in earth history like extinctions, and orogenies which happen intermittently.
B) The passage of time has been speeding up and the length of the day is variable.
C) They were originally all of equal duration but most of them got eroded and are full of unconformities.
D) It is based on evolution and some creatures are slow learners.

Question 43

The task of matching geologic formations of the same age over vast distances (like between continents) is termed .

A) correlation
B) lithification
C) cross dressing
D) stratification

Question 44

Which two Paleozoic, geologic, time-scale periods used in the United States are combined into the Carboniferous period in Europe and elsewhere?

A) Permian; Pennsylvanian
B) Mississippian; Pennsylvanian
C) Cambrian; Ordovician
D) Triassic; Jurassic

Question 45

What is the Jurassic Period named after?

A) 19th century Canadian geologist Sir William Jurass
B) the Jurassic Park movies
C) a moon of Saturn
D) Jura Mountains between France and Switzerland

Question 46

Which of the following is not a very long- lived, radioactive isotope?

A) U- 238
B) C- 14
C) K- 40
D) Rb- 87

Question 47

An unconformity is a buried .

A) surface of erosion with older strata above and younger strata below
B) fault or fracture with younger strata above and older strata below
C) fault or fracture with older rocks above and younger rocks below
D) surface of erosion or non- deposition separating younger strata above from older strata below

Question 48

Consider the names of the eras in the geologic time scale. What is meant by "zoic"?

A) rocks; lithified strata
B) life; living things
C) ancient
D) animals

Question 49

An unconformity is .

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 below

Question 50

Which geologic eon denotes the first 800 million years of Earth history?

A) Hadean
B) Chaldean
C) Archean
D) Proterozoic

Question 51

Which rocks are most useful in unraveling Earth's geologic history?

A) meteorites
B) fossiliferous sedimentary rocks
C) high grade metamorphic rocks
D) phaneritic igneous rocks

Question 52

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

A) xenon- 143
B) argon- 40
C) radon- 226
D) carbon- 14

Question 53

What geologic law/principle states that fossil organisms (fauna) changed and evolved in a definite, progressive way such that strata of specific ages can be recognized by the fossils they contain?

A) fossil exhibitionism
B) fossil transubstantiation
C) fossil superposition
D) fossil succession

Question 54

What is the source of natural carbon- 14?

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 flares

Question 55

The radioactive isotopes uranium- 238, uranium- 235, and thorium- 232 eventually decay to different, stable, daughter isotopes of .

A) iron
B) strontium
C) argon
D) lead

Question 56

While the Precambrian represents 88% of Earth's history, it is not divided into periods or epochs like the Phanerozoic because there .

A) were no multi- cellular organisms nor hard- bodied fauna to leave much of a fossil record
B) are few resources in Precambrian rocks and few geologists take an interest in them
C) are few remaining Precambrian rocks to correlate or divide due to active tectonics
D) are no Precambrian sedimentary rocks to use for internal divisions

Question 57

The study of paleontology focuses on ?

A) palinspastic restorations of deformed strata that were once horizontal
B) sedimentary rocks and their diagenetic transformations after deposition
C) absolute age determinations on minerals from igneous and metamorphic rocks
D) fossils and evidence concerning ancient life forms

Question 58

Which of the following means to recognize, identify, and describe similar- aged strata or similar lithologies in nearby areas or in widely separated, different areas?

A) strata- titling
B) fossicking
C) coagulation
D) correlation

Question 59

How can radiometric dating yield reliable values for the ages of minerals, rocks and some fossils?

A) One only needs to analyse for the parent isotope.
B) The decay constants are fixed and well measured for isotopic decay.
C) There are absolute fossil ages to compare to and test the radiometric clocks.
D) The physical conditions that control decay, like temperature and pressure, are always well known.

Question 60

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

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

Question 61

Which geologic event or feature has the crucial contact relations to help you determine that fault B is younger than fault A, even though they don't directly contact each other?

Question 62

Which have been around longer, the benthonic foraminifera or planktonic ones?

Question 63

What kind of unconformity is the most common and why?

Question 64

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?

Question 65

What is the important limitation of the K/Ar radiometric clock?

Question 66

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