Hanson earth and space ch 17 exam
The average rate of sediment deposition for rocks such as limestone and sandstone is ____________________.
30 cm per 1,000 years
A period of erosion shows up in layers of rock as a. an unconformity. c. a fault. b. a varve. d. an intrusion.
A
An isotope has a mass number of 83 and an atomic number of 36. How many electrons does each atom of the isotope have? a. 36 c. 83 b. 47 d. 119
A
Elements that emit atomic particles and energy are called a. radioactive. c. magnetic. b. stable. d. fluorescent.
A
Environmental conditions during the Mesozoic Era especially favored the survival of a. reptiles. c. birds. b. woolly mammoths. d. early humans.
A
Fossils found exclusively in the rock layers of a particular geologic age are called a. index fossils. c. metamorphic fossils. b. gastrolith fossils. d. complete fossils.
A
Gastroliths are a. polished stones. c. bones. b. footprints. d. plants.
A
How many years of deposition are probably represented in the diagram? a. 3.5 c. 6.5 b. 5 d. 7
A
Sedimentary deposits that form in glacial lakes and show definite annual layers are called a. varves. c. sills. b. dikes. d. crossbeds.
A
Sedimentary rocks are generally laid down in nearly horizontal layers called a. strata. c. foliates. b. striations. d. sheets.
A
Which process forms fossils by drying the organic matter in an organism's body? a. mummification c. excretion b. petrification d. deposition
A
Which type of unconformity consists of sedimentary layers above metamorphic or igneous rock? a. a nonconformity c. a disconformity b. an angular unconformity d. a uniformity
A
A fossil animal with its skin and muscles intact was most likely preserved through the process of a. petrification. c. carbonization. b. freezing. d. casting.
B
An isotope has an atomic number of 29 and a mass number of 63. How many neutrons does each atom of the isotope have? a. 29 c. 63 b. 34 d. 92
B
Approximately how old is a layer of rock containing Phacops fossils? a. 245 million years c. 100 million years b. 400 million years d. 10 million years
B
Calcium-41 has a half-life 80,000 years. At the end of 320,000 years, how much calcium-41 would remain in a sample initially containing 240 micrograms? a. 4 micrograms c. 60 micrograms b. 15 micrograms d. 120 micrograms
B
Nickel-63 has a half-life of 92 years. At the end of 184 years, how much nickel-63 would remain in a sample initially containing 20 micrograms? a. 2 micrograms c. 8 micrograms b. 5 micrograms d. 10 micrograms
B
Paleontology is defined as the study of a. rock layers. c. erosion. b. fossils. d. unconformities.
B
Potassium-40 has a half-life of 1.3 billion years. A very large sample originally contained 8 g of potassium-40, but now contains only 2 g of that isotope. How many half-lives have passed? a. 1 c. 3 b. 2 d. 4
B
The principle of uniformitarianism states that a. rocks can be dated by the radioactive elements they contain. b. geologic processes that occurred in the past are still at work today. c. rock layers that are buried are older than the layers above them. d. the major geologic features of the earth all formed at the same time.
B
Which of the following principles would most likely be used to determine the relative age of undisturbed sedimentary strata? a. principle of uniformitarianism c. principle of intrusion b. law of superposition d. law of crosscutting relationships
B
Which of the following rock layers in the diagram have the same relative age? a. 1 and 6 c. 3 and 7 b. 2 and 9 d. 5 and 10
B
Which two types of fossils are most likely to be found together in a single rock layer? a. graptolites and trilobites c. coprolites and petrified plants b. casts and molds d. imprints and amber drops
B
A rock contains 4 mg of a radioactive isotope. At the end of 60 years, only 0.5 mg of the element remains in the rock. What is the half-life of the element? a. 60 years c. 20 years b. 30 years d. 15 years
C
Geologic evidence shows that the first land plants began to grow during which time period or era? a. Precambrian c. Paleozoic b. Cenozoic d. Mesozoic
C
Tar seeps are formed by thick deposits of a. clay. c. petroleum. b. amber. d. silica.
C
The most accurate method of finding the absolute age of a rock is by a. varve-count dating. c. radiometric dating. b. erosion-rate dating. d. superposition dating.
C
The topmost layer in the diagram was most likely deposited during a. summer. c. winter. b. spring. d. fall.
C
Which feature in the diagram contains the youngest rock? a. 1 c. 5 b. 4 d. 6
C
Which of the following is a common petrifying mineral? a. garnet c. pyrite b. diamond d. feldspar
C
Which of the following is an example of a trace fossil? a. an intact shark tooth c. a dinosaur footprint b. a petrified log d. an insect in amber
C
Which of the following would most likely be dated using C-14? a. Hawaiian lava c. an ancient skeleton b. varves d. an igneous intrusion
C
Which type of unconformity is the most difficult to identify by sight in rock strata? a. nonconformity c. disconformity b. angular unconformity d. crossbed intrusion
C
A nonerosional boundary between two layers of sedimentary rock is called a a. foliation band. c. disconformity line. b. stratification barrier. d. bedding plane.
D
The absolute age of a rock layer can be determined by studying the a. superposition of adjacent rock layers. b. crosscutting relationships within the rock. c. position of ripple marks on the rock bed. d. ratio of U-238 to Pb-206 in the rock.
D
The sediment layers in the diagram are called a. molds. c. casts. b. imprints. d. varves.
D
Which feature in the diagram contains the oldest rock? a. 1 c. 3 b. 2 d. 4
D
Which of the following is produced when folded or tilted rock layers undergo erosion and then a new horizontal layer is deposited? a. a folded intrusion c. a bedding plane b. a cross-bedded fault d. an angular unconformity
D
Which of the following isotopes is most appropriate for dating a sample that is between 8,000 and 20,000 years old? a. uranium-238 c. potassium-40 b. thorium-234 d. carbon-14
D
Which of the following would be used to determine the difference in the relative ages of the rock in layer 6 and layer 3 in the diagram above? a. law of superposition c. varve counts b. principle of average erosion rates d. law of crosscutting relationships
D
Which of the following would most likely be used to determine the relative age of a fault? a. law of superposition c. principle of uniformitarianism b. radioactive decay d. law of crosscutting relationships
D
Which of the following would most likely be used to determine the relative age of a rock layer? a. carbon-14 analysis c. crystal shape analysis b. mineral content analysis d. guide fossil analysis
D
Which type of fossil would yield the most information about the internal structure of an organism? a. a tree imprint c. a tree mold b. a tree cast d. a petrified tree
D
A fault is always older than the rocks through which it cuts.
F
A frozen mastodon is an example of a trace fossil.
F
A species that lived during several different geologic time periods would make a good index fossil.
F
According to the law of crosscutting relationships, an intrusion is older than the rocks through which it cuts.
F
An organism will undergo mummification only if it is buried by sediments at the bottom of a glacial lake.
F
Carbon-14 is a radioactive isotope used to determine the absolute age of rocks.
F
Disconformities are produced when folded or tilted rock layers undergo weathering.
F
Erosion rates have been used to establish the age of the Grand Canyon accurately.
F
Measuring the rate of sediment deposition is the most accurate method of determining the absolute age of a geologic feature.
F
One varve represents two years of deposition of sedimentary particles.
F
The principle of uniformitarianism states that all the earth's geologic features formed at the same time.
F
The radioactive decay rate is greatly affected by temperature.
F
The index fossils discussed in the text that lived approximately 400 million years ago are called ____________________.
Phacops
A disconformity is a type of gap in the geologic record.
T
A footprint is an example of a trace fossil.
T
An organism is most likely to be preserved through the process of mummification in the desert.
T
Coprolites can be used to study the eating habits of ancient animals.
T
Entire animals can be fossilized in tar seeps.
T
Fossil spores and pollen indicate that Antarctica had a much warmer climate 40 million years ago.
T
Geologists use index fossils to help locate oil and natural gas deposits.
T
In an angular unconformity, the bedding planes of older rock layers are not parallel to the bedding planes of younger layers.
T
James Hutton stated that the geologic formations on the earth's crust took millions of years to develop.
T
Mold fossils generally provide little information about the internal structures of the original organisms.
T
Nonconformities occur between horizontal rock layers.
T
Ripple marks can be used to determine the original arrangement of rock layers in an area.
T
The earth is believed to be about 4.6 billion years old.
T
The final product of radioactive decay is usually a nonradioactive isotope.
T
The hard parts of an organism, such as bones and teeth, are usually the only parts of the body to be preserved in the rock record.
T
The law of superposition could be used to determine the relative age of a sequence of igneous lava flows.
T
The laws of superposition and crosscutting relationships could be used to determine the relative age of an unconformity.
T
Varves form through the process of sedimentation.
T
Scientists use index fossils to determine a rock's ____________________.
absolute age
In the diagram above, point B represents a type of rock feature called ____________________.
an angular unconformity
The boundary labeled A in the diagram above represents a(n) ____________________.
bedding plane
Fossils formed when mud fills in a mold and hardens are called ____________________.
casts
The relative age of an igneous intrusion would most likely be determined by using the law of ____________________.
crosscutting relationships
What did scientists measure to determine the approximate age of Niagara Falls? ____________________
erosion rates
The change in living things over time is called the process of ____________________.
evolution
Fossils such as trilobites that can be used to establish the age of a rock are called ____________________.
index fossils
The principle that can be used to determine the relative age of layers 1 through 3 in the diagram above is the ____________________.
law of superposition
The principle that states that each sedimentary rock layer is older than the layers above it and younger than the layers below it is called the ____________________.
law of superposition
An unconformity that consists of stratified sedimentary rock above a horizontal basalt surface would be classified as a type of ____________________.
nonconformity
Scientists who study fossils to learn about the earth's geologic history are called ____________________
paleontologists
Small waves formed on the surface of sand by the action of water or wind are called ____________________.
ripple marks
Layers in sedimentary rock are called ____________________.
strata
Breaks in the geologic record that make it difficult to determine the relative age of rock layers are called ____________________.
unconformities
The principle that states that current geologic processes are the same processes that occurred in the past is known as the principle of ____________________.
uniformitarianism
Light and dark banding patterns in the sediments of glacial lakes are called ____________________.
varves