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WorksheetsUnits 4-5 Test Review
Total questions: 55
Worksheet time: 2hrs 50mins
Which is NOT a true statement about Earth’s history or the age of its materials?
Radioactive materials in rocks can be used by geologists as clocks to determine the age of a rock.
Meteorites found on Earth cannot be older than the age of Earth.
Geologists estimated Earth’s age to be about 4.6 billion years old based on evidence from the moon and
meteorites from our solar system that have fallen to Earth’s surface.
The primordial Earth had no crust or oceans, and its atmosphere was different from the modern atmosphere.
Which is NOT a true statement?
When two consecutive layers are deposited without detectable interruption of geologic time, the layers are said to be conformable.
When two consecutive layers are deposited with detectable interruption of geologic time, an unconformity is formed.
An unconformity is a bounding surface that represents a long interval of time for which no geologic record exists in that place.
An unconformity can only represent billions of years of missing geologic time in the rock record.
Which is a true statement about the geologic timescale?
The geologic time scale has the oldest divisions at the top.
The geologic time scale is never revised.
The geologic time scale is revised as more fossil assemblages are described around the world.
The geologic time scale is divided into three major eons.
Which is a true statement?
Index fossils are important because they originate from organisms that spread slowly.
Index fossils are abundantly preserved in the fossil record.
Index fossils existed for a long period of geologic time.
Index fossils are geographically isolated in the fossil record.
Which is a true statement?
Ages are the longest increment of time on the geologic timescale.
Eras are subdivided into periods.
Periods are subdivided into ages.
The geologic timescale was originally made on the basis of carbon dating.
Which isotope would be helpful to determine absolute age of a rock?
Carbon-12
Carbon-14
Uranium-283
Rubidium-78
Which is NOT a true statement?
The Precambrian eon includes the Hadean, Archean, and Proterozoic eons and represent all geologic time before the Cambrian period.
The Precambrian eon represents approximately 90 percent of all geologic time.
The Precambrian eon is a time when fossil remains were very abundant.
The oldest division of the Precambrian is the Hadean eon and the youngest division is the Proterozoic eon.
How long ago did Earth form?
about 2.34 billion years ago
about 3.45 billion years ago
about 4.56 billion years ago
about 5.67 billion years ago
What do scientists use to study the Precambrian (early earth) time?
fossils from tiny microscopic animals
ore from eroded and deformed rocks
fossils from algae and other simple plants
fossils from dinosaurs
Which of the following gases was NOT found in Earth’s original atmosphere?
nitrogen
carbon dioxide
water vapor
oxygen
Cyanobacteria lived in Earth's early oceans where they -
produced oxygen.
were land-dwelling organisms.
needed oxygen.
were tiny plants that used nitrogen
Which of the following describes how Earth’s atmosphere changed during the Hadean, Archean, and Proterozoic eons?
The amount of carbon dioxide increased.
Torrential rains never reached the surface until the Paleozoic era.
The amount of oxygen increased.
Precambrian oxygen was quickly used up by plants.
What was the first period of the Paleozoic era?
Precambrian
Cambrian
Ordovician
Siberian
One major tectonic event that characterizes the late Carboniferous period is -
the formation of the southern continent of Gondwana.
the formation of the supercontinent of Pangaea.
a land bridge between North and South America.
the formation of the Appalachian Mountains.
The breakup of Pangaea occurred during the -
Cambrian period.
Paleozoic era.
Mesozoic era.
Cenozoic era.
Most scientists believe the extinction of Mesozoic life was caused by -
a large-scale earthquake.
solar flares.
a series of volcanic eruptions.
a collision with a large meteorite.
The term Cenozoic means -
recent age.
age of reptiles.
age of mammals.
recent life.
The major animal group that replaced dinosaurs and reptiles in the Cenozoic era was -
lobe-finned fishes.
amphibians.
mammals.
birds.
Rocks record geological events and -
life forms of the present.
life forms of the past.
astronomical milestones of the past.
Earth’s circumference and diameter in the past.
The geologic processes that shape Earth’s features today -
are much different from those of thousands of years ago.
did not operate in the distant past.
are basically the same today as they were in the
geologic past.
became important only several hundred years ago.
For what purpose do geologists use relative dating?
to determine which rock layer in a canyon wall formed first
to find the age of a rock layer
to determine how a rock’s composition has changed over time
to identify past life forms that once lived in a rock layer
In general, the law of superposition states that in an undeformed sequence of sedimentary rocks, each layer is -
about the same age.
older than the one below it.
older than the one above it.
thicker than the one above it.
According to the principle of cross-cutting relationships, an intrusive rock body is -
deposited as sedimentary layers.
younger than the rocks it intrudes into.
always made of the same materials as rock around it.
older than the rocks it intrudes into.
Which type of geologic event has to occur to create an angular unconformity?
uninterrupted deposition of sediment
igneous intrusion into layered rock
sediment deposited on older, eroded igneous rock
folding or tilting of rock layers
The laws of superposition and original horizontality are best applied to -
all rock types.
igneous rocks.
sedimentary rocks.
metamorphic rocks
What are fossils?
the oldest layers of rock in a region
the remains or traces of an organism preserved from the geologic past
living creatures with habitats in or around rock
objects that people of long ago left behind as artifacts
Which of the following environments would NOT contain fossils?
sediment deposited in a riverbed
intrusive rock formed from cooled magma
a thick deposit of dried mud
layers of sand that accumulated over thousands of years
Index fossils allow geologists to -
match rocks of the same age in different regions.
determine the exact age of rocks.
identify organisms that did not leave fossil evidence behind.
determine why some organisms became extinct
The principle of fossil succession states that different types of fossil organisms -
generally leave behind hard parts.
occur most often in sedimentary rock.
succeed one another in a definite order.
are older in the deepest layers of rock.
Radioactivity is produced when unstable nuclei -
bond.
break apart.
become cooler.
expand.
If the half-life of an unstable isotope is 10,000 years and only 1/8 of the radioactive parent remains, how old is the sample?
10,000 years old
20,000 years old
30,000 years old
40,000 years old
Radiocarbon dating is used to date -
geologic events up to 75,000 years ago.
geologic events up to 10,000 years ago.
geologic events more than 1 million years ago.
all geologic events of the past.
Which two substances are involved in carbon-14 dating?
carbon-12 and carbon-10
carbon-14 and uranium-238
lead-206 and carbon-14
carbon-14 and carbon-12
Why is radiometric dating on sedimentary rocks usually unsuccessful?
Sedimentary rocks are too young.
Sedimentary rocks form from many older rock particles.
Sedimentary rocks never have particles that contain radioactive isotopes.
Sedimentary rocks form too quickly to be accurately dated.
When did the Phanerozoic eon begin?
about 2.0 million years ago
about 540 million years ago
about 10.1 million years ago
about 20.5 billion years ago
The largest expanse of time on the geologic time scale is the -
eon.
epoch.
era.
period.
About 88 percent of Earth’s history is within the time period before the Phanerozoic eon, called the -
Cambrian.
Paleozoic.
Cenozoic.
Precambrian.
The time known as the Precambrian began approximately (a) billion years ago.
The era following the Proterozoic eon was the (a) .
The (a) period of the Paleozoic era could be referred to as the “age of fishes.”
The breakup of Pangaea began in the (a) period.
A large meteorite is believed to have caused the massive extinction that occurred at the end of the (a) era.
The Cenozoic era spans from about 65 million years ago to ____ _______.
(a)
The extinction of the dinosaurs at the end of the Mesozoic benefited (a) during the Cenozoic.
Relative dating tells geologists the (a) in which events occurred.
The principle of original horizontality states that layers of sediment are usually deposited in a(n) (a) position.
Pieces of one rock unit that are contained within another are (a) .
The type of unconformity shown in Diagram A is a(n) (a) .
The type of unconformity shown in Diagram B is a(n) (a) .
The type of unconformity shown in Diagram C is a(n) (a) .
The process in which rock layers in different regions are matched is (a) .
A half-life is the amount of time needed for one half of the (a) in a sample to decay to form its stable isotope.
Radiometric dating allows geologists to determine the (a) of some rocks and minerals.
It is hard to use radiometric dating to tell the age of (a) rocks because the age of the minerals in them may not represent when the rocks actually formed.
The three eras within the Phanerozoic eon are the ____________ (ancient life), ___________ (middle life), and the _____________ (recent life).
(a)
