Geohistory

1. Rock 'A' was formed during the Mississippian Epoch and rests upon rock 'B' which rests upon rock 'C' which was formed during the Silurian Period. If rock `B' is neither Mississippian nor Silurian, during what time period did it form?

Cambrian
Devonian
Pennsylvanian
Permian

2. Rock layers from which of the following Periods would not be found in New York State?

Devonian
Silurian
Ordovician
Permian

3. According to the Earth Science Reference Tables, which radioactive element, formed at the time of the Earth's origin, has just reached about one half-life?

Carbon-14
Uranium-238
Potassium-40
Rubidium-87

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



A
B
C
E

5. 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

6. 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.

7. 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

8. The chief reason why it is difficult to correlate pre-paleozoic rocks, such as those on the Canadian Shield, is that

The outcrops are very widely distributed.
Pre-paleozoic rocks are distinctly different from those formed later.
Areas where pre-paleozoic rocks occur makes it hard to collect data.
Few, if any, fossils are found in pre-paleozoic rocks.

9. The best basis for concluding that a certain layer of shale rock in New York State was deposited at the same time as one in California is that both

Are at the same distance below the surface.
Contain similar fossil remains.
Are sedimentary rocks.
Have the same chemical composition.

10. An unconformity exists between which two rock layers?



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

11. 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

12. According to the Referance Tables, near which community in New York State would you be least likely to find fossils?

Old Forge
Albany
Elmira
Watertown

13. Which statement about dinosaurs is supported by information provided in the Reference Tables?

Dinosaur fossils first appeared in rocks of the Paleozoic Era.
Dinosaurs did not eat grass.
Dinosaur fossils and trilobite fossils may be found in the same rocks.
Dinosaurs lived only on land.

14. 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

15. During which time period was the majority of exposed bedrock in New York State deposited?

Precambrian
Mesozoic
Cenozoic
Paleozoic

16. 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

17. 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

18. 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

19. 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.

20. 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.

21. 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.

22. 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

23. 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

24. 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.

25. According to the Reference Tables, as one travels eastward from the Tug Hill Plateau into the Adirondack Mountains, the age of the rocks changes from

Devonian to Silurian
Ordovician to Silurian
Precambrian to Cambrian
Ordovician to Precambrian

26. 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

27. 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.

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

Increases
Decreases
Remains the same

29. According to the Reference Tables, between which two cities in New York State would the oldest surface bedrock be found?

Plattsburgh and Watertown
Jamestown and Rochester
Utica and Binghamton
Syracuse and Albany

30. 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.

31. According to the Geologic Time Scale in the Reference Tables, what is the estimated age of the Earth as a planet in millions of years?

570
4000
4600
5000

32. A timeline is made on a strip of paper to illustrate the Earth's history. A length of 1.0 centimeter is used to represent 10 million years. According to the Reference Tables, what distance should be used to represent the Mesozoic Era?

0.16 cm.
1.6 cm.
16 cm.
160 cm.

33. 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.

34. For which period of geologic history is there no rock record in New York State?

Cretaceous
Permian
Quaternary
Jurassic

35. A scientist wishes to search for fossils of the earliest amphibians. Near which city in New York State should she search?

Ithaca
Watertown
Old Forge
Niagra Falls

36. 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.

37. A rock sample contained 8 grams of potassium-40 when it was formed but now contains only 4 grams due to radioactive decay. Based on the Reference Tables, what is the approximate age of this rock?

1.0 billion years
1.3 billion years
40 million years
5,700 years

38. 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.

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

Dinosaurs
Armored fish
Earliest birds
Mammoths

40. Which fossils could be found in Silurian limestone?

Reptiles
Eurypterids
Mammals
Flowering plants

41. According to the Earth Science Reference Tables, dinosaur footprints may be preserved in Triassic and Jurassic rock. In which section of New York State would these footprints most likely be found?

Northeastern
Southwestern
Central
Southeastern

42. 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

43. 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

44. What kind of fossils might be found in the rocks of the Tug Hill Plateau?

Earliest reptiles
Amphibians, ammonoids, and sharks
Earliest birds
Graptolites

45. At which New York State city is the oldest bedrock located?

Rochester
Watertown
Massena
Old Forge

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



1
6
3
5

47. During which period of New York State geohistory did rifting occur?

Jurassic
Permian
Devonian
Ordovician

48. A paleontologist discovers a rock layer containing brachiopod index fossil 'Y'. What other fossils might be found in this rock layer?

First mammal-like reptiles
Mastodonts
Earliest insects
Dinosaurs

49. A geologist uses carbon14 to date a sample. He find that the sample contains C14 to N14 in the ratio of 1:7. What is the age of the sample?

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

50. A geologist is studying the bedrock at 43 degrees 30 minutes north, 75 degrees, 45 minutes west. What kind of fossils should she expect to find at this location?

Corals and echinoderms
Dinosaurs
Earliest reptiles
Earliest placental mammals

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