Deck 5: Rocks Fossils and Time Making Sense of the Geologic Record

Question 1

Lithostratigraphic properties yield stronger time correlations than biostratigraphic properties.

Answer 1

False

Question 2

A marine transgression is a period of lower sea level.

Answer 2

False

Question 3

Lithostratigraphic units are defined solely on the basis of fossil assemblages.

Answer 3

False

Question 4

Rocks above and below an unconformity are related.

Question 5

The fossil record reveals the true diversity of ancient plant and animal life.

Question 6

In a marine transgression, sediments within a sedimentary facies are deposited at the same time.

Question 7

Formations consist of rocks that are all the same age.

Question 8

A body of sediment with distinctive physical, chemical, and biological properties is a facies.

Question 9

Fossils are remains or traces of prehistoric life that have been preserved in rocks of Earth's crust.

Question 10

A transgression occurs when the sea advances landward.

Question 11

A shell of an ancient marine bivalve is an example of a body fossil.

Question 12

Lithostratigraphic correlations are made on the basis of similarity of rock type over wide areas.

Question 13

Biostratigraphic units are based on fossil assemblages and are called biozones.

Question 14

Walther's Law states that facies in a conformable vertical sequence will also occur in a lateral sequence.

Question 15

Stratigraphy is irrelevant when examining relationships among metamorphic and igneous rocks.

Question 16

The rock layers in the Grand Canyon were deposited during marine transgressions and regressions.

Question 17

A formation is the basic subdivision of biostratigraphic units.

Question 18

Fossils are useful in the study of historical geology for determining relative ages of strata, depositional environments, and evidence for evolution.

Question 19

Time units are rock units that were deposited during a certain time interval.

Question 20

The period of time not represented by strata in an unconformity is a hiatus.

Question 21

An erosional surface that separates older metamorphic or plutonic rocks from younger overlying sedimentary rocks is called a(n) ____.

A) angular unconformity
B) disconformity
C) nonconformity
D) hiatus
E) bedding plane

Question 22

What process is used to demonstrate that two rock strata are equivalent?

A) equivalency.
B) interpolation.
C) extrapolation.
D) correlation.
E) integration

Question 23

Change in sea level is most affected by ____.

A) precipitation
B) evaporation
C) river influx
D) rates of seafloor spreading
E) glacial ice volumes and tectonic activity

Question 24

The Devonian system refers to the rocks deposited during the time of the Devonian period.

Question 25

What is the correct order of conformable sedimentary facies, from shoreline toward open water?

A) shale → mud → sand
B) limestone → sand → conglomerate
C) limestone → shale → mud
D) sandstone → shale → limestone
E) mud → sandstone → shale

Question 26

Not all fossils contain the direct remains of an organism.

Question 27

An unconformity in which stratified sedimentary rocks overlie an erosional surface cut into igneous or metamorphic rocks is called a(n)____.

A) nonconformity
B) disconformity
C) guide fossil
D) transgression
E) angular unconformity

Question 28

An erosional surface that separates strata that are parallel with one another is called a(n) ____.

A) angular unconformity
B) disconformity
C) nonconformity
D) hiatus
E) bedding plane

Question 29

Range zones ____.

A) are formations that are lithologically similar
B) consist of one rock layer
C) consist of one rock type
D) represent periods of time over which lithologically similar rocks are deposited
E) mark the first and last appearance of a fossil

Question 30

What is t he most commonly used time unit, all of which have corresponding time-stratigraphic units?

A) erathem
B) era
C) period
D) epoch
E) eonothem

Question 31

Although igneous rocks are the easiest to date radiometrically, most fossils are preserved in sedimentary rocks.

Question 32

The basic lithostratigraphic unit is a mappable unit of strata with distinctive upper and lower boundaries called a(n) ____.

A) series
B) extrusive
C) formation
D) rock
E) biozone

Question 33

Remains or traces of prehistoric organisms preserved in rocks are ____.

A) fossils
B) evaporites
C) formations
D) natural selections
E) minerals

Question 34

Preserved records of prehistoric organic activity such as tracks, trails, burrows, and nests are called ____.

A) trace fossils
B) carbonizations
C) casts
D) molds
E) permineralizations

Question 35

The statement that "the same facies following one another in a conformable vertical sequence will also replace one another laterally" is known as ____.

A) Gressly's principle
B) principle of fossil succession
C) Smith's Law of Conformity
D) Steno's axiom
E) Walther's Law

Question 36

An erosional surface that separates inclined strata below from flat lying strata above is called a/an ____.

A) angular unconformity
B) disconformity
C) nonconformity
D) hiatus
E) bedding plane

Question 37

A break or gap in the geologic record resulting from erosion or nondeposition or both is a(n) ____.

A) inclusion
B) cast
C) formation
D) extinction
E) unconformity

Question 38

Which of the following is a trace fossil?

A) mammal tooth
B) frozen mammoth
C) preserved mosquito in amber
D) dinosaur footprint
E) clam shell mold

Question 39

Organisms in terrestrial environment have a better chance of being preserved as fossils.

Question 40

A great example of a trace fossil would be the impression left by a crawling trilobite, an extinct arthropod.

Question 41

____________________ provide the only record of prehistoric life.

Question 42

According to the principle of ____________________, fossil assemblages succeed one another through time in a regular and determinable order.

Question 43

The principle of faunal succession is based on the fact that fossils ____.

A) remain the same over time
B) are confined to distinct geographic regions
C) are widespread
D) succeed one another through time in an order
E) are found in all rock types

Question 44

You observe two shale beds separated by 300 kilometers. The rocks in the two shale beds are similar, but one bed is several million years older than the other. You can conclude both beds ____.

A) are time-correlated
B) contain the same guide fossils
C) are lithologically correlated
D) are time correlated and contain the same guide fossils
E) are unrelated

Question 45

A body of strata recognized on the basis of its fossil assemblage is a(n) ____________________ unit.

Question 46

In a sequence of undisturbed sedimentary rocks, the oldest fossils will be ____.

A) in the top rock layer
B) in the middle rock layer
C) in the bottom rock layer
D) unable to be determined
E) indistinguishable from the other fossils

Question 47

Radiometrically dating a muscovite grain in a sandstone would give ____.

A) the date the sandstone was deposited
B) the age of the sandstone
C) the date the sandstone lithified
D) The absolute age of the muscovite grain
E) no conclusive evidence of date or age

Question 48

A marine regression is characterized by ____.

A) rocks that get younger in the direction of land
B) igneous intrusions caused by seafloor spreading
C) rocks that get younger in a seaward direction
D) the presence of one facies
E) the deposition of a single rock type

Question 49

____________________ is largely responsible for developing the principle of fossil succession (also called the principle of faunal succession).

Question 50

____________________ form when ____________________ are filled with minerals and sediment.

Question 51

When the remains of a buried organism dissolve and leave a cavity, the resulting structure is called a(n) ____________________.

Question 52

Boundaries that separate individual strata from one another are called ____________________.

Question 53

Guide fossils are most useful because they ____.

A) occur over a small geographic area
B) occur over a brief time interval
C) are difficult to identify
D) occur over a long period of time
E) occur in all rock types

Question 54

The three types of unconformities are ____________________, ____________________, and ____________________.

Question 55

A clast of granite found in a breccia is dated at 450 million years old. What can you conclude about the breccia?

A) The breccia is older than 450 million years.
B) The breccia is younger than 450 million years old.
C) The breccia was metamorphosed more than 450 million years ago.
D) The breccia was metamorphosed fewer than 450 million years ago.
E) You can't draw any conclusions.

Question 56

The ____________________ ____________________ provides evidence for physical and biological events of Earth's history.

Question 57

What is one way for an unconformity to develop?

A) erosion
B) deposition
C) transgression
D) regression
E) lithification

Question 58

When minerals replace the bodily remains during fossilization, we say the fossil has been ____.

A) molded
B) dissolved
C) altered
D) indexed
E) regurgitated

Question 59

Fossils that are easy to identify, widespread, and existed for a short time geologically are called ____________________.

Question 60

What would occur if all of the ice on Greenland and Antarctica melted?

A) marine regression
B) marine transgression
C) glacial transgression
D) continental transgression
E) continental regression

Question 61

Why is the statement, "The Jurassic system lasted from 200-146 million years ago," incorrect? How would you correct it? In your explanation, be sure to distinguish between time-stratigraphic units and time units.

Question 62

Why are most fossils found in sedimentary rock, rather than in igneous or metamorphic rocks?

Question 63

Discuss William Smith's principle of fossil succession. Why is this principle important in relative geologic dating?

Question 64

Discuss the branch of geology called stratigraphy and how the fundamental geologic principles are used to unravel stratigraphic relationships.

Question 65

Discuss the application of absolute dates to the relative Geologic Time Scale. What are the limitations of this application?

Question 66

Discuss Walther's law and its application to determine marine transgressions and regressions.

Question 67

Disconformities exist between parallel layers of sedimentary rocks, and consequently, are hard to identify. What geologic process must occur for an unconformity to develop? What is one way to identify a disconformity, other than numerical dating?

Question 68

Compare and contrast the three types of unconformities. What differences in geologic history do these three types imply?

Question 69

Compare and contrast regression and transgression. What sea level changes do these geologic sequences imply? What could cause these changes? Give specific examples of regressive and transgressive sequences.

Question 70

Two layers of limestone are found 200 kilometers apart. Give two lines of evidence that could show the layers are correlated.