Deck 9: Geologic Time

Question 1

What is a fossil?

A)Evidence of past life that can include skeletal as well as trace material
B)Only the hard parts of a skeletal structure that have been preserved
C)Mudcracks preserved in sedimentary rock
D)A really old geologist

Answer 1

A

Question 2

When rocks are ________, several adjacent layers were deposited without interruption.

A)included
B)dissolved
C)conformable
D)cross-cut

Answer 2

C

Question 3

________ was the English engineer and canal builder who observed that sedimentary strata in widely separated areas could be identified by their distinctive fossil assemblages.

A)Isaac Newton
B)William Smith
C)Charles Lyell
D)Charles Darwin

Answer 3

B

Question 4

A(n)________ is a type of unconformity with parallel beds above and below the erosional surface.

A)fossil conformity
B)nonconformity
C)disconformity
D)angular unconformity

Question 5

When correlating rock between widely separated areas or between continents, what feature(s)do geologists rely on the most to link distant rock units of similar age?

A)Rock type
B)Sedimentary structures
C)Fossils
D)Mineral content

Question 6

Which scientist is credited with developing the law of superposition?

A)James Ussher
B)Charles Lyell
C)James Hutton
D)Nicholas Steno

Question 7

When a shell is buried in sediment and subsequently dissolved, a cavity called a ________ is left behind.When this cavity is later filled with sediments, a ________ is created.

A)mold; gastrolith
B)trace; burrow
C)mold; cast
D)amber; carbonization

Question 8

Which of the following is an example of a trace fossil?

A)A spider encased in amber
B)Petrified wood
C)Gastroliths
D)A skeleton

Question 9

Which of the following is an example of a relative date?

A)The Cenozoic era began sixty-five million years ago.
B)A headstone in a cemetery has the date a person died.
C)The Declaration of Independence was written in 1776.
D)The Silurian period came before the Devonian period.

Question 10

What is stratigraphic correlation?

A)Dividing up rock layers into new ones based on mineral content
B)Matching up rocks of similar age in different regions
C)Putting events in order from first to last
D)Matching up continental coasts based on matching shapes

Question 11

What is the definition of relative dating?

A)Putting events in order from first to last
B)Using radioactive materials to determine an age
C)Counting tree rings to determine an age
D)Calculating dates based on the theory of relativity

Question 12

Which of the following best describes the principle of faunal succession?

A)Rock layers will extend equally in all directions until they pinch out or reach the edge of a basin.
B)Fossil organisms succeed one another in a specific and identifiable order.
C)Only the most successful organisms will survive climatic extremes.
D)Faults are younger than the materials they cut across.

Question 13

What scientific development made accurate numerical dating possible?

A)Discovery of radioactivity
B)Correlation of rock layers
C)Development of radar
D)Discovery of X-rays

Question 14

What is the definition of an inclusion?

A)A fossil of an organism that existed for a short period of geologic time
B)A fragment of one rock unit enclosed in another rock unit
C)An unstable isotope decaying into a stable form
D)A fault bisecting a layer of rock

Question 15

________ is the scientific study of fossils.

A)Quaternary geology
B)Volcanology
C)Geomorphology
D)Paleontology

Question 16

Which of the following is an example of a numerical date?

A)The Stone Age occurred before the Iron Age.
B)John Adams was president of the United States after George Washington.
C)A meteorite impacted the Earth sixty-five million years ago.
D)Dinosaurs descended from reptiles, which descended from amphibians.

Question 17

The principle of ________ states that organisms succeed one another in a definite, determinable order that can be used to recognize a specific time period.

A)correlation
B)superposition
C)fossil succession
D)lateral continuity

Question 18

What is an index fossil?

A)An organism that existed for a vast period of time and is representative of an era
B)An organisms that is restricted to one small, geographic setting
C)A trace fossil that defines a colony of organisms
D)An organism that was geographically widespread but limited to a short span of geologic time

Question 19

A black, organic residue of an ancient fern would be an example of which type of fossilization?

A)Permineralization
B)Mummification
C)Replacement
D)Carbonization

Question 20

A worm burrow is an example of which type of fossilization?

A)Mummification
B)Cast and mold
C)Carbonization
D)Trace fossil

Question 21

A neutron is a combination of a(n)________ and a(n)________.

A)cation; isotope
B)nucleus; electron
C)electron; proton
D)ion; isotope

Question 22

What is the definition of a half-life?

A)The parent isotope half of a radiometric dating pair
B)Half the time it takes for the parent isotope to decay to the daughter
C)The time it takes for half of the parent isotope to decay to the daughter
D)Half of the alpha particles necessary to decay at a steady rate

Question 23

For what reason might the nuclei of atoms break apart in radioactivity?

A)There are too many neutrons in the nucleus.
B)Electrons are being shared by two adjacent atoms.
C)Forces that bind protons and neutrons together are weak.
D)Protons are being exchanged between atoms.

Question 24

Which era are we currently in?

A)Mesozoic
B)Precambrian
C)Paleozoic
D)Cenozoic

Question 25

The ________ period on the geologic time scale is a historic name that has now largely been replaced by the Paleogene and Neogene periods.

A)Carboniferous
B)Hadean
C)Quaternary
D)Tertiary

Question 26

What is the half-life of potassium-40?

A)1)3 billion years
B)704 million years
C)14.1 billion years
D)4)5 billion years

Question 27

What does "-zoic" in the eras of the geologic time scale refer to?

A)Life
B)Water
C)Rock
D)Fossilization

Question 28

A deposit of volcanic tuff contains the isotope potassium-40, which is slowly decaying into argon-40.How might the apparent age of the sample be affected if the volcanic tuff is heated and remains heated for a long period of time?

A)The rate of decay will speed up.
B)The sample will appear older than it really is.
C)The sample will appear younger than it really is.
D)Heat will have no effect on the age of the sample.

Question 29

What materials are best dated with carbon-14?

A)Igneous rocks
B)Volcanic rocks
C)Organic materials
D)Sandstones

Question 30

What is the effective maximum range for carbon-14 dating?

A)100,000 years
B)70,000 years
C)10,000 years
D)13,000 years

Question 31

________ is a term used to define 88% of Earth's history prior to the start of the Paleozoic era.

A)Quaternary
B)Precambrian
C)Paleogene
D)Jurassic

Question 32

Which two conditions are the most important in order for an organism to become fossilized?

A)Rapid death and oxygen-free environment
B)Rapid burial and possession of hard parts
C)Rapid mineralization and rapid desiccation
D)Rapid decay and possession of soft tissues

Question 33

If ²³⁵U has 92 protons, how many neutrons does it have?

A)25
B)92
C)143
D)235

Question 34

You are trying to determine the age of a lava flow using an isotope with a half-life of 1.5 million years.If the sample has gone through four half-lives, what is the age of the rock?

A)1)5 million years
B)6 million years
C)375,000 years
D)5 billion years

Question 35

In what era is the Jurassic period?

A)Precambrian
B)Paleozoic
C)Mesozoic
D)Cenozoic

Question 36

Which particle of an atom will determine the atomic number of an element?

A)Proton
B)Nucleus
C)Neutron
D)Electron

Question 37

What is a fossil assemblage?

A)A fossil that is geographically widespread but limited to a short span of geologic time
B)A fossil that is very common and existed for a long period of geologic time
C)A group of fossils used to establish the age of a rock unit
D)Fossil organisms that have survived multiple geologic eras

Question 38

You are an archaeologist researching artifacts left behind by Francisco Pizzaro's conquest of Peru in the 1530s.In order to confirm the authenticity of the leather artifacts, you are performing radiometric dating using an isotope pair that has a half-life of 250 years.In order for the artifacts to date back to the time of Pizzaro's conquest, approximately how much original radioactive isotope must be left in the artifacts?

A)50%
B)25%
C)75%
D)12.5%

Question 39

What is an isotope?

A)An atom that has more or fewer neutrons than it should
B)An atom that has more or fewer electrons than it should
C)An atom that has double the protons of a stable atom
D)A nucleus of an atom that has split during the decay process

Question 40

________ is a technique where the decay rate of radioactive isotopes is measured and used to determine the age of a geologic material.

A)Electron Capture
B)Radiometric Dating
C)Ion Exchange
D)Half-Life

Question 41

Carbon-14 dating is useful for paleontologists researching dinosaurs.

Question 42

A basalt dike is found in a body of granite.Which is older and why?

Question 43

A detrital sedimentary rock can be radiometrically dated because the clasts formed at the same time as the rock.

Question 44

Name the periods of the Paleozoic era in order from oldest to youngest.

Question 45

In radioactive decay, an unstable ________ isotope will decay into a stable ________ isotope.

A)ion; carbon
B)parent; daughter
C)daughter; parent
D)neutron; ionized

Question 46

Numerical dating is putting events in order from first to last.

Question 47

Which of the following would make the best index fossil: olenellus (522-510 million years ago), flexicalymene (~490-418 million years ago), and phacops (~418-360 million years ago).

A)Olenellus
B)Flexicalymene
C)Phacops

Question 48

The white granite of the Idaho Batholith near Boise, Idaho, contains dark gray xenoliths of metamorphic material.Which is older? How do you know?

A)Granite; the principle of superposition
B)Xenoliths; the principle of cross-cutting relations
C)Granite; the principle of unconformities
D)Xenoliths; the principle of inclusions

Question 49

One method of geologic dating is dendrochronology, or the science of tree ring dating.Based on what you know about tree rings, how could you determine the age of the tree? Would this be an example of relative dating or numerical dating?

Question 50

The fossil record is biased toward preserving organisms with hard parts.

Question 51

What is the ultimate source for naturally occurring carbon-14?

A)Cosmic ray collisions and neutron capture involving nitrogen
B)Dissolution of carbonate rocks
C)Decay of unstable parent isotopes to create a stable carbon-14
D)Volcanic eruption and emission of greenhouse gases

Question 52

All isotopes are unstable.

Question 53

Assume that a modern rabbit dies and becomes fossilized.Which of the following groups of animals would represent an accurate fossil assemblage to find with that rabbit?

A)Coral, brachiopods, and fish
B)Squirrels, birds, and mice
C)Trilobites, brachiopods, and clams
D)Fish, birds, and coral

Question 54

The oldest rocks on Earth date back to 4.28 billion years old and were found in western Australia.

Question 55

The first life on Earth developed during the Cambrian period.

Question 56

The Mississippi River cuts through Silurian-aged dolomite between northwestern Illinois and eastern Iowa.Which is older? How do you know?

A)Dolomite;the principle of superposition
B)Mississippi; the principle of original horizontality
C)Dolomite; the principle of cross-cutting relationships
D)Mississippi; the principle of lateral continuity

Question 57

Hadean is an informal term used by many geologists to refer to the earliest interval of Earth's history.

Question 58

A Devonian-aged limestone contains fossils of brachiopods and bryozoans.What do these fossils indicate about the environment during the Devonian period?

A)Arid desert
B)Coastal swamp
C)Delta
D)Shallow marine

Question 59

By putting events in order, scientists can use the order to determine how long ago certain geologic events took place.

Question 60

In cast and mold fossilization, the cast is the hollow space in the rock made when a fossil is buried in sediment.

Question 61

Assuming that humans went extinct today, do you think that they would be good index fossils? Why or why not?

Question 62

Which rock layer is the oldest in this image?

Question 63

Which rock layer is the youngest in this image?

Question 64

What kind of unconformity is visible in this figure? The unconformity in the question is indicated by the Arrow B.

A)Disconformity
B)Nonconformity
C)Angular unconformity

Question 65

Compare and contrast the three common types of radioactive decay: alpha particle decay, beta particle decay, electron capture.Your answer should include how the atomic mass and the atomic number of the isotope have changed.

Question 66

Why is it that scientists know less about the first four-fifths of Earth's history than about the last, most recent one-fifth?

Question 67

What geologic feature is present in this image?

Question 68

Explain how the feature in this image formed.

Question 69

You are studying an outcrop where the base layer is limestone and the layer directly on top of that is sandstone.Near the base of the sandstone are small, weathered pieces of limestone entirely contained within the sandstone.Explain how these pieces of limestone came to be contained within the sandstone.

Question 70

What kind of unconformity is visible in this figure? The unconformity in question is indicated by the Arrow A.

A)Disconformity
B)Nonconformity
C)Angular unconformity