Chapter 5 Review

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Chapter 5 Test Review

Instructions: Click on the button to see if your answer is correct or not. I recommend keeping track of how many you get correct on your first try.

What is the relative age of a fault that cuts across many rock layers?

The fault is older than all of the layers it cuts across.

The fault is younger than all the layers it cuts across.

The fault is the same age as the bottom layer it cuts across.

The fault is the same age as the top layer it cuts across.
Layers of volcanic ash often serve as useful geologic time markers because ash layers usually

darken with age.

can be sampled easily.

are older the the surrounding rock.

deposit quickly over a wide area.
In which way are index fossils and volcanic ash deposits similar?

Both strongly resist chemical weathering.

Both often serve as geologic time markers.

Both can usually be dated with radiocarbon.

Both normally occur in non-sedimentary rocks.
Which is the best method of determining the relative ages of a layer of sandstone in western New York State and a layer of sandstone in eastern New York State?

compare the colors of the two layers

compare the thickness of the two layers

compare the index fossils in the two layers

compare the size of sand particles of the two layers
Older layers of rock may be found on top of younger layers of rock as a result of

joints in the rock layers.

weathering processes.

overturning of rock layers.

igneous extrusions.
Which type of rock is most likely to contain fossils?

metaconglomerate

granite

gneiss

shale
What is the estimated age of the Earth?

4.6 x 10⁶ years

4.6 x 10⁷ years

4.6 x 10⁸ years

4.6 x 10⁹ years
According to fossil evidence in the geologic record, which of these life-forms appeared on Earth most recently?
placental mammals

flowering plants

sharks

birds
If a sample of a radioactive substance is crushed the half-life of the substance will
decrease.

increase.

stay the same.
Which statement about the species of animals and plants that lived on Earth in the past is best supported by the fossil records?
Most became extinct.

Most lived on the land.

Most were preserved in metamorphic rock.

Most appeared during the Cambrian Period.
Unconformities (buried erosion surfaces) provide evidence that

many life-forms have become extinct.

faults are older than the rock in which they are found.

part of the geologic record has been destroyed.

metamorphic rocks have formed from sedimentary rocks.
Why are radioactive substances useful for measuring geologic time?

The ratio of decay products to to radioactive substances remains constant in rocks.

The half-lives of radioactive substances are short.

Samples of radioactive substances are easy to collect from rocks.

Radioactive substances undergo decay at a predictable rate.
Compared to the length of time for the first half-life of a sample of a radioactive isotope, the length of time for the second half-life is

less.

more.

the same.
An archeologist found an ancient skeleton estimated to be 10,000 to 25,000 years old. which radioactive isotope would be the most useful for finding the age of the skeleton?

Carbon-14

Potassium-40

Uranium-238

Rubidium-87
An ancient bone was analyzed and found to contain carbon-14 that had decayed for nearly two half-lives. Approximately how old is the bone?

1,400 years.

2,800 years

5,600 years

11,000 years
Theories of evolution suggest that variations between members of the same species give the species greater probability of

remaining unchanged.

surviving environmental changes.

becoming fossilized.

becoming extinct.
Which of the following is NOT a characteristic that would make a good index fossil?

The species had hard parts, such as shells, bones, or teeth.

The species lived over a large geographic area.

The species lived over a very long geologic time scale.

The species lived over a small geologic time scale.
Which bedrock feature is most useful in correlating sedimentary bedrock in one area with sedimentary bedrock in another area?
index fossils

cementing agent

texture

color
Which of the following would have fossil remains that could be dated to the Early Pleistocene?
armored fish

trilobites

mastodons

dinosaurs
Which geologic time span could mammoths be found?
Pleistocene Epoch

Pennsylvanian Epoch

Precambrian Era

Paleozoic Era
The largest meteorite impact crater in North America formed approximately 1,850 million years ago, which was during the
Middle Archean Era

Early Proterozoic Era

Early Jurassic Period

Late Cretaceous Period

The Diagram below represents the present number of decayed and undecayed atoms in a sample that was originally 100% radioactive materials.

The Green represents the remaining isotope.

The Blue represents the amount of decay-product.

If the half-life of the radioactive material is 2,000 years, what is the age of the sample represented by the diagram?

1,000 years

2,000 years

3,000 years

4,000 years

What is the fraction of original Carbon-14 remaining after 34,200 years?
1/8 grams

1/16 grams

1/32 grams

1/64 grams
Which statement best explains the changing appearance of the horse over the last 50 million years, as supported by the fossil record?
The horse evolved due to the influence of humans.

The horse evolved from a complex life-form to a simpler life-form.

The horse evolved into a life-form better able to survive.

The horse evolved from larger ancestors without forelimbs.
Did dinosaurs ever eat people?
Yes, all of the time.

No, dinosaurs did not bother with people because they could not catch people, and if they did, the people were too small to fill them up.

No, dinosaurs did not like the taste of people.

No, dinosaurs and people did not live at the same time.
The age of an igneous intrusion is 50 million years. What is the most probable age of the rock immediately surrounding the intrusion?

10 million years

25 million years

40 million years

60 million years
The diagram below represents bedrock of different ages beneath a location in New York State.

Top

Devonian

Silurian

Ordovician

Cambrian

Bottom

Assuming that the rock layers have not bee overturned and that no unconformity exists, at which location is this bedrock found?

Albany

Elmira

Old Forge

Osego
Fossils would most likely be found in a sample of

limestone

granite

quartzite

metaconglomerate
During which geologic time period did the earliest reptiles and great coal-forming forests exist?

Devonian

Quaternary

Mississippian

Pennsylvanian
Which radioactive isotope is most useful for determining the age of mastodont bones found in late Pleistocene sediment?

Uranium-238

Carbon-14

Potassium-40

Rubidium-87
The half-life of a radioactive substance is mainly controlled by the

amount of the substance.

composition of the substance.

pressure acting on the substance.

temperature of the substance.
A bone sample contains only 1/4 of its original radioactive C¹⁴ content. How old is the bone sample?

1 C¹⁴ half-life

2 C¹⁴ half-lives

3 C¹⁴ half-lives

4 C¹⁴ half-lives
Which two elements are most useful for the radioactive dating of recent organic remains?

C¹⁴ and N¹⁴

K⁴⁰ and Ca⁴⁰

U²³⁸ and Pb²⁰⁶

Rb⁸⁷ and Sr⁸⁷
The absolute age of a rock is the approximate number of years ago that the rock formed. The absolute age of an igneous rock can best be determined by

comparing the amounts of decayed and undecayed radioactive isotopes in the rock.

comparing the sizes of the crystals found in the upper and lower parts of the rock.

examining the rock's relative position in a rock outcrop.

examining the environment in which the rock is found.
Approximately how long ago did the first dinosaurs appear on earth?

66 million years ago

187 million years ago

230 million years ago

374 million years ago
Which sequence of New York State index fossils shows the order in which the organism appeared on Earth?
What is the name of the New York State Fossil?

Elliptocephala

Dicellograptus

Eurypterus

Brachiopods

Base your answers to questions 38 through 41 on the geologic cross section below. Overturning has not occurred.
Which statement can be said of the dike and sills shown in the cross section?

These are igneous intrusions.

These are igneous extrusions.

These are sedimentary rock.

These were first to form in this landscape.
Which rock type is the oldest?

sandstone

limestone

granite

conglomerate
Which feature is represented by symbol along the edges of the dike and sills?

contact metamorphic rock

an unconformity

a glacial moraine

index fossils
Which statement correctly describes an age relationship in the geologic cross section below?

The top layer of sandstone is older than the top layer of shale.

The conglomerate is younger than the bottom layer of sandstone.

The granite is older than the bottom layer of sandstone sandstone.

The granite is younger than the top layer of sandstone sandstone.