GoMyClass Practice Test - J. Marso (yes, you may use this test)

Geo-History: Geologic Time

 

1. Which of the rock formations in the diagram is the youngest?



A
B
C
E

2. The best method for the correlation of sedimentary rock layers several hundred kilometers apart is by comparing the

Index fossils in the layers
Layers by walking the outcrop
Thickness of the rock layers
Color of the rock layers

3. A log is found incorporated in a sequence of layered sediments at the bottom of a lake. Which method would most accurately locate the time period when the tree was living?

Counting the tree rings.
Counting the sedimentary layers.
Radiocarbon dating.
Uranium-lead dating.

4. The decay curves of 4 radioactive elements are shown on the graph. Which curve represents the element with the shortest half-life?



A
B
C
D

5. An unconformity exists between which two rock layers?



3 and 6
5 and 6
2 and 4
1 and 3

6. The half-life of a particular radioactive substance

Decreases as pressure on it increases
Increases as the temperature increases
Decreases as its mass decreases
Is independent of mass, temperature and pressure

7. The physical and chemical conditions which long ago produced changes on the Earth's surface are still producing changes today. This statement is one way of stating the principle of

Catastrophism
Diastrophism
Uniformitarianism
Isostacy

8. How are ancient volcanic ash deposits important to geologists.

They are easily dated using carbon-14
They form resistant rock layers which can be easily walked out.
They are good time markers because they have wide distribution.
They indicate rapid continental drift

9. Unless a series of sedimentary rock layers is overturned, the bottom rock layer usually

Contains fossils
Is the oldest
Contains the greatest variety of minerals
Has the finest texture

10. Which of the following is the correct sequence of rock layers from oldest to youngest?



F - E - D - C - B - A
A - B - C - D - E - F
F - E - C - D - B - A
D - E - F - C - B - A

11. Which of the following statements is true of half-life?

It is different for different radioactive substances.
It changes at different times for the same substance.
It is generally shorter for substances under high pressure.
It depends on the amount of radioactive substance left.

12. Why is carbon-14 not usually used to accurately date objects more than 50,000years old?

Carbon-14 has a short half-life and too little is left after 50,000 years.
Carbon-14 has a long half-life and not enough has decayed by 50,000 years.
Carbon-14 has been introduced as an impurity in objects 50,000 years old.
Carbon-14 has only existed on Earth during the last 50,000 years.

13. In a certain section of sedimentary rock, fossil dating shows that younger rock layers are on top of older rock layers. This relationship indicates that

The rock layers were formed according to the principle of superposition.
The rock layers have been overturned.
Fossil dating is often inaccurate.
The sediments that formed the rock layers were made of many minerals.

14. A geologist uses carbon-14 to measure the age of material found in a sedimentary deposit. If the half-life of carbon-14 is 5,700 years and the sample shows that only 25% of the original carbon-14 is left, the age of the sample is

5,700 years
11,400 years
17,100 years
22,800 years

15. Which is the correct sequence of events for this location?



H - G - F - D - Folding - A - Fault (X-Y) - Erosion - C - B - Erosion
H - G - F - E - Fault (X-Y) - Folding - D - A - C - B - Erosion
A - H - G - F - E - Folding - Fault (X-Y) - D - Erosion - B
H - G - F - E - D - Folding - Fault (X-Y) - A - Erosion - C - B - Erosion

16. The fossil remains of organisms which were once common and widespread but which survived only during a short period of geologic time might be especially useful for

Correlating sedimentary deposits in places distant from each other.
Establishing the absolute age of a deposit.
Tracing the evolution of organisms related to that species.
Determining some of the factors that lead to extinction.

17. Rock layer M is Devonian sandstone. Rock layer B is Ordovician siltstone. In which geologic period may rock layer F have been deposited?



Cambrian
Devonian
Carboniferous
Permian

18. A simple, direct method of correlating rocks of one outcrop is to

Date the rocks using uranium-lead ratios.
Walk out the layers.
Follow the line of a fault.
Compare the age of unconformities.

19. If a specimen of a given radioactive substance is heated to 500 degrees C, its half-life

Increases
Decreases
Remains the same

20. Which of the following statements about the geologic cross-section is correct?



Igneous intrusion 3 is older than igneous intrusion 2.
Layers 1 and 6 were deposited before layers 4 and 5 were tilted.
The fault, B, is older than both igneous intrusion 2 and 3
A long period of erosion took place before the deposition of layer 6.

21. Which two forms of life existed together on the Earth during the same time period

Dinosaurs and mastodons.
Trilobites and birds.
Flowering plants and trilobites.
Mastodons and flowering plants.

22. The fossil record indicates that most of the plants and animals that lived on Earth in the past

Appeared during the Cambrian Period.
Became index fossils.
Have become extinct.
Lived on land.

23. Geologic history is divided into units on the basis of

Radioactive dating.
The amount of rock deformation.
The thickness of sedimentary rocks.
The fossil record.

24. The fossil record provides evidence that primitive humans were alive on Earth at the same time as the

Dinosaurs
Armored fish
Earliest birds
Mammoths

25. Index fossils are useful for correlating rocks because the fossils

Contain radioactive carbon-14 which is used for relative dating
Are found only in sedimentary rocks
Represent organisms that lived for a short time in widespread areas
Represent organisms that lived near the Earth's surface for a long time

26. What caused the Acadian Orogeny?

The spreading of the sea floor beneath the Atlantic ocean
The collision of North America and Avalon and the closing of the remaining part of the Iapetus Ocean
Uplift and faulting along the Pacific - North American plate boundaries
The breakup of Pangea

27. In which rock layer would fossils least likely be found?



1
6
3
5

28. A geologist uses carbon-14 to measure the age of material found in a sedimentary deposit. If the half-life of carbon-14 is 5,700 years and the sample shows that only 25% of the original carbon-14 is left, the age of the sample is

5,700 years
11,400 years
17,100 years
22,800 years

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