TEST 2 yallll
5) "This rock is fifteen million years old," is an example of ________. A)a numerical date B)a relative date C)superposition D)the principle of cross-cutting relationships
A)a numerical date
52)After three half-lives, ________ of an original, radioactive, parent isotope remains and the rest has decayed into the daughter isotope.
Answer: 12.5% or one-eighth (1/8)
15) If the Wingate Sandstone was deposited in the Triassic period and the Carmel Formation in the Jurassic, a visitor to Bryce Canyon National Park shouldn't expect to find any strata older than the ________period. A) TriassicB) Cretaceous C) PermianD) Tertiary
Answer: A
20) Why isn't the Precambrian more finely divided into sub-divisions like periods and epochs? A)Fewer and less diverse fossils exist in Precambrian rocks. B)Precambrian rocks don't have radioactive isotopes in them. C)Geologists just don't care about the Precambrian the way they do about more recent time periods. D)The Precambrian lacks the igneous rocks that are most useful for radiometric dating.
Answer: A
21) Which of the following describes radioactive decay by beta particle emission? A)The atomic number of the daughter isotope is one more than the parent; the mass numbers are the same. B)The daughter isotope has an atomic number one less than the parent and a mass number two less. C)The mass number of the daughter isotope is one more than the parent and both isotopes have the same atomic number. D)The daughter isotope has an atomic number two less than the parent and a mass number four less.
Answer: A
13) Which unit(s) are shared by Grand Canyon National Park and Zion National Park? A)Toroweap and Kaibab B)Kaibab and Monekopi C)Moenkopi and Chinle D)Kaibab only
Answer: B
14) Since the Moenkopi Formation was deposited at the end of the Permian period and the very beginning of the Triassic, and the Navajo Sandstone was deposited at the end of the Triassic and into the Jurassic, what is the age of the Chinle Formation? A)Permian B)Triassic C)Jurassic D)Cambrian
Answer: B
17) Which of the following is an essential characteristic of an index fossil? A)The organism lived in a very specific environment or two, such as tropical volcanic islands. B)The organism lived for a very limited period of geologic time. C)The fossils of the organism are exceptionally well preserved. D)The organism lived on the land, not in the ocean.
Answer: B
18) Using the known rates of radioactive decay to date the crystallization of certain minerals is known as ________ dating. A) conventional B) radiometric C) relative D) fossil assemblage Answer: B 19) The earliest 88 percent of geologic time is represented by the time span informally called the ________. A) Paleozoic B) Precambrian C) Mesozoic D) Phanerozoic
Answer: B
23) A worm would stand a poor chance of being fossilized because ________. A) worms were very rare during the geologic past B) worms have no hard parts C) worms contain no carbon-14 D) worms live in the shallow ocean
Answer: B
16) Use the geological cross-section to determine the age of rock layer D as precisely as possible. A)It is 40 million years old. B)It is between 39 million years old and 25 million years old. C)It is between 39 million years old and 17 million years old. D)It is older than 17 million years old.
Answer: C
22) Sandstone strata and a mass of granite are observed to be in contact. Which of the following statements is correct? A)The sandstone is younger if the granite contains sandstone inclusions. B)The sandstone is younger if it shows evidence of contact metamorphism. C)The granite is older if the sandstone contains pebbles of the granite. D)The granite is older if it contains inclusions of sandstone.
Answer: C
7) Examine the geologic timescale shown here. Which is the earliest period listed in the Mesozoic? A) Cambrian B) Permian C) Triassic D) Cretaceous
Answer: C
48)We now live in the ________ era.
Answer: Cenozoic
24) Which is most useful for determining the age of the raisins in raisin bread, relative to the bread in which they are found? A) principle of superposition B) principle of original horizontality C) principle of cross-cutting relationships D) principle of inclusions
Answer: D
25)The process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas is called superposition.
Answer: FALSE
26)Fossils of an organism can be found in rocks older than the organism itself.
Answer: FALSE
27)The strata shown on the left can be correlated with units J, I, and H, on the right.
Answer: FALSE
31) The further back in geologic time we go, the more detail we can discern about conditions on the ancient Earth.
Answer: FALSE
32) The four basic units that make up the geologic time scale are the eon, the aria, the episode, and the period.
Answer: FALSE
35 ) James Hutton's proclamation that "we find no vestige of abeginning-no prospect of an end" is a concise summary of the philosophy of catastrophism.
Answer: FALSE
39)Permineralizationand carbonization are methods of correlating rock units.
Answer: FALSE
49) All of geologic time prior to the beginning of the Paleozoic era is commonly referred to as the ________.
Answer: Precambrian
28)Assuming that this is an undisturbed sedimentary sequence (that is, superposition is valid), and that unit G is Cambrian in age, unit F could be Ordovician.
Answer: TRUE
29)Alpha emission, beta emission, and electron capture are three different kinds of radioactive decay.
Answer: TRUE
30)The Phanerozoic, Proterozoic, and Archean are all eons.
Answer: TRUE
33) A granite dike cuts across a shale. The dike gives a radiometric date of 84 million years old. The shale was therefore deposited more than 84 million years ago.
Answer: TRUE
34) The geologic time scale was devised before the techniques for numerical dating using radioactivity were developed.
Answer: TRUE
36) "John is older than Susan" is an example of a relative date.
Answer: TRUE
37) Sedimentary layers can be important indicators of past environmental conditions that existed when the sediments were deposited.
Answer: TRUE
38)According to the figure, the age of the Dakota Sandstone must be less than 160 million years, and greater than 66 million years old.
Answer: TRUE
51)When radioactive potassium-40 decays, the stable daughter isotope ________ is produced.
Answer: argon-40
46)A sandstone is found to overlie a shale. The shale contains a volcanic ash layer that has been radiometrically dated to 84 million years ago. Both the shale and the sandstone are cut by a pluton of gabbro that has been dated to 60 million years old. How old is the sandstone layer? ________
Answer: between 84 and 60 million years old
45) Examine the figure that shows the age ranges of some fossil groups. If trilobites ranged from the Cambrian to the Permian, and ferns ranged from the Devonian until the present day, then rock unit B must have been deposited ________.
Answer: between the Devonian and the Permian
43) The process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas is ________.
Answer: correlation
53)A(n) ________ is an erosional unconformity with parallel beds or strata above and below.
Answer: disconformity
47)The remains or traces of prehistoric life are called ________.
Answer: fossils
44) The amount of time it takes for half of the remaining radioactive isotopes to decay is the ________ of a isotope system.
Answer: half-life
42)A lava flow includes fragments of limestone in it. Which rock unit is older, the lava flow or the limestone? ________
Answer: limestone
50)Would a pigeon or a penguin make a better index fossil for the present day? ________
Answer: pigeon
54)Most sedimentary rocks cannot be dated directly by ________ methods.
Answer: radiometric
41)All else being equal, in a horizontal sequence of sedimentary rock layers, each higher bed is younger than the bed below it. This idea is the principle of ________.
Answer: superposition
40) The idea of ________ suggests that the physical, chemical, and biological laws that operate today have also operated in the geologic past.
Answer: uniformitarianism
6) The longest subdivision of the geologic time scale is the ________. A) epoch B) eon C) era D) period
B) eon
9) Why do the eras of the Pharnerozoic eon all end with "zoic"? A) They are based on rock called zoisites. B)These names refer to life or living things; they invoke the changes in fossil organisms from one era to the next. C)"Zoic" means "time" in Latin D)These eras were all first described near the London Zoo, so the names pay tribute to that location.
B)These names refer to life or living things; they invoke the changes in fossil organisms from one era to the next.
8) A datable mineral crystal contains 40% parent isotope. How many half-lives have passed since the crystal formed? A)1 B)more than 1 but less than 2 C)more than 2 but less than 3 D)more than 3
B)more than 1 but less than 2
7) Examine the geologic timescale shown here. Which is the earliest period listed in the Mesozoic? A) Cambrian B) Permian C) Triassic D) Cretaceous
C) Triassic
12) The principle of ________ is the concept that ancient life forms evolved in a definite order and therefore their fossils can help determine thegeologic ages of strata. A)superposition B)cross-cutting relationships C)fossil succession D)fossil assemblage
C)fossil succession
10) Who first formulated the principle of uniformitarianism? A)Aristotle B)Lyell C)Steno D)Hutton
D)Hutton
11) Which of the following geologic observations would NOT bear directly on working out the sequence of geologic events in an area? A) inclusions of sandstone in a granite pluton B)a well-exposed dike of basalt in sandstone C)an unconformity between a granite and sandstone D)the feldspar and quartz contents of a granite
D)the feldspar and quartz contents of a granite
E)fossil tree sap
amber
F)the defunct notion that the Earth is only a few thousand years old, and that all geologic change is accomplished rapidly through violent events
catastrophism
H)the remains or traces of ancient life
fossil
A)fossil poop
fossil assemblag
D)a group of fossils that co-existed at the same time. Their overlapping ranges can help constrain the age ofa rock unit that contains them
fossil assemblag
B)a fossil organism that is restricted to a certain brief stretch of geologic time, but was widespread and abundant during its time on Earth
index fossil
G)indirect evidence of ancient life, such as footprints, bite marks, and gastroliths
trace fossil
C)the notion that we can understand the geologic past by focusing on present day processes and physical laws; geologic change may be slow or gradual
uniformitarianism
