Geol 122 FINAL EXAM
A "daughter" isotope is produced when a "parent" isotope undergoes radioactive decay. What is the Parent-to-Daughter ratio after one half-life? A. 2:1 B. 1:1 C. 1:3 D. 1:2
B
What is the agent of metamorphic change during contact metamorphism? A. hydrothermal fluids B. increased temperature C. differential stress D. increased pressure
B
What is the key difference between crystalline rocks and clastic rocks? A. their chemical composition B. how the grains/crystals are held together C. how much silica they contain D. the location they formed
B
What is the most likely environment to accumulate sediments that would subsequently produce a biochemical sedimentary rock like limestone? A. coastal delta environment B. warm, tropical marine water C. mountain stream D. coastal wetland
B
Where is Earth's magnetic field produced? A. inner core B. outer core C. mantle D. magnetosphere
B
The change in wavelength (and, therefore, frequency) of waves that happens if the source of the waves is moving (either towards or away from the observer) is explained by the ________. A. expanding Universe theory B. Doppler effect C. Big Bang theory D. nebular theory
C
Dinosaurs first appeared during the ____ period. A. Permian B. Cambrian C. Devonian D. Triassic
D
SiO4(4-), and CO3(-2) are all examples of: A. cations B. organic compounds C. silicate minerals D. anions
D
Slaty cleavage, schistosity, and compositional banding are all examples of ____. A. metamorphic facies B. mineral cleavage C. recrystallization D. foliation
D
The primary evidence that our Sun is a third-, fourth-, or fifth-generation star comes from the fact that our _____? A. solar system is too large to be first generation B. sun is too large to be a first-generation star C. sun is too hot to be a first-generation star D. solar system contains too many heavy atoms to be first generation
D
Yellowstone (in northwest Wyoming) is a classic example of which type of volcanism? A. mid-ocean ridge B. oceanic hot spot C. subduction zone D. continental rift
D
Eighty percent of Earth's continental area had formed by the end of the ___ period. A. Archean B. Holocene C. Paleozoic D. Hadeon
A
Felsic magmas have higher silica content than mafic magmas A. true B. false
A
Generally speaking, which climate would yield the thickest/most developed soil? A. tropical B. polar C. temperature D. desert
A
In the diagram below, what is the correct order of rock types that would form in each location? A. sedimentary, igneous, metamorphic, sedimentary, igneous
A
Interplanetary space is more dense than interstellar space A. True B. False
A
Most of the mass in our solar system is in: A. the sun B. pluto C. earth D. Jupiter
A
Mt St. Helens, a_______volcano, experienced an ________eruption in 1980? A. stratovolcano, explosive B. shield, effusive C. stratovolcano, effusive D. shield, explosive
A
Once an ancient mountain range is destroyed by erosion, what evidence can geologists look for to learn of its past existence? A. crust containing igneous activity, deformation, and metamorphism B. high, rugged peaks C. there is no detectable record of destroyed mountain ranges D. fossils of mountain-dwelling plants and animals
A
The mineral class that makes up >95% of the continental crust is termed: A. silicates B. carbonates C. oxides D. halides
A
Trace amounts of impurity in a mineral can commonly produce significant differences in ________ among individual crystals of this mineral. A. color B. luster C. hardness D. cleavage
A
True or false: when a source rock undergoes partial melting, the resulting magma has a higher silica content than the source rock A. true B. false
A
What is the basis for the modern classification of rocks? A. origin or genetic scheme of the rock B. size of the rock C. age of the rock D. chemical composition of the rock
A
Which of the following Earth layers is liquid? A. outer core B. upper mantle C. crust D. inner core
A
Olivine, quartz, and hornblende are all silicate minerals. Olivine is an independent tetrahedra; quartz is a framework silicate; and hornblende is a double-chain silicate. Rank these three minerals from lowest to highest % silicon. A. quartz, hornblende, olivine B. olivine, hornblende, quartz C. hornblende, olivine, quartz D. hornblende, quartz, olivine
B
Presently, Earth's atmosphere is dominated by which two gases? A. oxygen and carbon dioxide B. nitrogen and oxygen C. carbon dioxide and sulfur dioxide D. hydrogen and helium
B
Temperature and pressure decrease within the interior of Earth as you progress from the crust to the core A. True B. False
B
The breakdown of rock into small fragments and dissolved ions is termed_________. A. deposition B. weathering C. transportation D. lithification
B
The most common minerals on the Earth's surface are _____. A. carbonates B. silicates C. oxides D. hydroxides
B
The process of low-grade metamorphic rocks being altered to form high-grade metamorphic rocks is termed ____________ metamorphism. A. foliated B. prograde C. dynamic D. retrograde
B
Uniformitarianism is succinctly summarized by which phrase? A. The future is the key to the present B. The present is the key to the past C. The present is the key to the future D. The past is the key to the present
B
What did geologists find in the geologic record that indicated the transition between the Precambrian and the Cambrian? A. evidence for orogenic (mountain building) events B. hard shells/skeletons that were well preserved as fossils C. a clay layer enhanced in iridium (rare on Earth) D. banded iron formations indicative of oxygenation
B
What is believed to be the primary cause of the "K-T Boundary Event?" A. volcanic eruptions B. the impact of a 13-km wide meteorite C. Siberian flood basalts D. a rowdy dinosaur
B
Whether an eruption will primarily produce lava flows (effusive eruption) or pyroclastic debris (explosive eruption) is NOT influenced by the ____ the source of magma. A. proportion of volatiles within B. depth and residence time of C. viscosity of D. composition of
B
Which gas found in today's atmosphere was largely absent during the Hadean and Archean eons? A. nitrogen B. oxygen C. carbon dioxide D. water vapor
B
Which of the following processes CANNOT occurs in the formation of metamorphic rock? A. the segregation of minerals into layers of different compositions B. complete remelting of the rock, followed by solidification to form a new rock C. the realignment of minerals so that they develop a preferred orientation D. the solid-state rearrangement of atoms or ions to create a new assemblage of minerals
B
Which of the three primary forms of volcanoes consist of alternating layers of tephra and solidified lava? A. shield volcano B. stratovolcano C. cinder cone
B
Which of these is not a means of classifying crystalline igneous rock? A. texture B. temperature C. chemical composition
B
While on a field trip, you find a layer of sedimentary rocks overlying an igneous basement rock. What type of unconformity did you discover? A. Disconformity B. Nonconformity C. Angular unconformity
B
At a mid-ocean ridge (a divergent boundary where new oceanic lithosphere is produced), what is the primary process responsible for producing magma? A. addition of volatiles B. heat transfer from rising mantle magma C. decompression melting
C
Can the age of Earth be reliably estimated from sediment thicknesses? A. No: sedimentary rocks make up only a small fraction of the rocks on Earth's surface B. Yes: sedimentation rates remain constant at any one locality throughout Earth's history C. No: much of Earth's history is represented by unconformities between strata rather than the strata themselves D. Yes: sedimentary rocks are rarely metamorphosed or melted
C
Explosive or voluminous eruptions may cause the volcano to collapse on the floor of the now-empty magma chamber, producing a broad depression termed a ___. A. crater B. fissure C. caldera D. lahar
C
How can physical weathering speed up the processes of chemical weathering? A. Chemical weathering requires salt, which is provided by physical weathering. B. Physical weathering produces minerals that are very susceptible to chemical weathering. C. Physical weathering increases the surface area available for chemical weathering to attack.
C
In an undisturbed sequence of sedimentary rocks, younger layers overlie older layers according to the principle of _____. A. original continuity B. uniformitarianism C. superposition D. original horizontality
C
In various tectonic settings (e.g., a continental rift), parcels of the asthenosphere rise closer to the Earth's surface. In this example, what is the process that leads to the formation of magma? A. melting due to a decrease in pressure B. melting due to an addition of volatiles C. melting due to heat transfer from rising magma
C
Injecting hot fudge into ice cream and causing the ice cream to melt is an appropriate analogy for which cause of magma melt? A. melting due to addition of volatiles B. decompression melting C. melting due to heat transfer from rising magma
C
Jointing, frost wedging, and thermal expansion are all types of ____________ weathering. A. serious B. rapid C. physical D. chemical
C
Of the minerals in the previous question, which has the greatest susceptibility to chemical weathering? A. hornblende B. quartz C. olivine D. they are all equal
C
Olivine, quartz, and hornblende are all silicate minerals. Olivine has an independent tetrahedra structure; quartz is a framework silicate; and hornblende is a double-chain silicate. Rank these three minerals in order of increasing (smallest to largest) amount of silicon. A. hornblende, olivine, quartz B. hornblende, quartz, olivine C. olivine, hornblende, quartz D. quartz, hornblende, olivine
C
On what basis was Pluto excluded from being classified as a planet? A. is a large celestial body orbiting a star B. has a nearly spherical shape C. has cleared its neighborhood for other objects
C
The distinction between the crust and the mantle is primarily on the basis of a difference in ____; the distinction between the lithosphere and the asthenosphere is primarily on the basis of a difference in _____. A. chemical composition; chemical composition as well B. color; chemical composition C. chemical composition; how it deforms D. how it deforms; chemical composition
C
The metal alloy that makes up the Earth's core is ___ than the mantle. A. less dense B. distinct in chemistry but of very similar density C. more dense D. very similar in chemistry and density
C
The primary difference between intrusive and extrusive igneous rocks is.... A.their composition B. their temperature C. whether they solidified above or below Earth's surface D. the type of volcano that produced them
C
The silica tetrahedron that forms the backbone of all the silicate minerals is composed of silicon and what other element? A. iron B. carbon C. oxygen D. magnesium
C
What is the approximate thickness of Earth's atmosphere? Consider the troposphere and stratosphere where most (99%) atmospheric gases are found. A. 100 meters B. 6400 kilometers C. 50 kilometers D. 1,500,000 kilometers
C
What process is responsible for producing elements with atomic numbers greater than #26? A. stellar nucleosynthesis B. Big Bang nucleosynthesis C. supernova
C
Which of the following would most commonly pose the greatest hazard to human life from an explosive volcanic eruption? A. volcanic gas B. falling ash C. pyroclastic flows D. flowing lava
C
A fast-moving flow consisting of a mixture of water and volcaniclastic debris is termed a ____________. A. flood basalt B. avalanche C. pyroclastic flow D. lahar
D
A radiometric age for a mineral crystal within an igneous rock measures the amount of time that has passed since the ____. A. temperature of the crystal became equal to the Curie point for the mineral B. atoms within the crystal were part of a body of molten magma C. partial melting occurred D. temperature of the crystal reached the closure temperature, meaning all atoms were subsequently retained
D
As a magma cools and experiences fractional crystallization, the remaining magma tends to have ________ silica at the end? A. increasing, but pressure staying nearly the same B. and pressure both decreasing C. remaining constant, but pressure increasing D. and pressure both increasing
D
Earth's surface is protected from solar wind and cosmic radiation by A. a large, metallic shield launched into orbit by NASA in the 1960s B. Earth's gravitational fiend C. a powerful stream of ions emitted by the sun D. Earth's magnetic field
D
Glass is different from a mineral because it _____. A. is not naturally occurring B. contains carbon and is therefore organic C. is not a solid D. does not have atoms arranged in an orderly pattern
D
In general, if a body of igneous (source) rock is subjected to partial melting, the magma that is produced is expected to be ________. A. more mafic than the source rock B. identical in chemical composition to the source rock C. the melt composition is not predictable D. more felsic than the source rock
D
Minerals are all naturally occurring solid substances with a definable chemical composition. They must also possess ____. A. metallic luster B. an ability to be synthesized in the laboratory as well as be found in nature C. metallic elements; such as iron, calcium, or magnesium D. a fixed orderly crystalline structure
D
Nitrogen and oxygen are... A. all of the above B. the two elements that form the mineral halite C. light chemical elements created in the first stage of Big Bang nucleosynthesis D. the major gases in Earth's atmosphere at present
D
Our Solar System formed _____ ago. A. 2.5 million years B. 13.8 billion years C. 13.8 million years D. 4.5 billion years
D
What is a primary characteristic of the Pleistocene Epoch? A. formation of the ancestral Rockies B. evolution of dinosaurs C. Significant changes in atmospheric oxygen levels D. repeated glacial/interglacial periods
D
What is the approximate age of the Universe? A. 2.5 billion years B. 4.5 billion years C. 66 million years D. 13.8 billion years
D
What is the most likely location to find metamorphic rocks formed via regional (dynamothermal) metamorphism? A. Mid-Atlantic Ridge B. Florida C. Marianas Trench D. the Himalaya
D
Which class of rocks is produced at mid-ocean ridges? A. explosive rocks B. metamorphic rocks C. sedimentary rocks D. igneous rocks
D
Which metamorphic process is characterized by the formation of new minerals from old minerals present in the protolith? A. plastic deformation B. recrystallization C. pressure solution D. neocrystallization
D
Which of the following is true concerning the 1980 eruption of Mt. St. Helens? A. the eruption produced the largest basalt flow of the 20th century anywhere on Earth B. no lahars were produced because the eruption occurred in the winter C. the eruption was a complete surprise to geologists and provided no forewarning D. the eruption was characterized by a very strong lateral blast
D
Which of the following processes CANNOT induce metamorphism? A. heat and pressure associated with deep burial B. contact with a hot pluton C. contact with hydrothermal fluids D. cementation and compaction of grains during diagenesis
D
As a body of magma cools and begins to crystallize, which type/class of minerals will be the first to form? A. mafic B. silicia C. intermediate D. felsic
A
As a magma cools and experiences fractional crystallization, the remaining magma tends to have ________ silica at the end? A. more B. the same amount C. less
A
Clastic sedimentary rocks are primarily classified on the basis of ________? A. grain size B. angularity C. degree of sorting D. mineral composition
A
Each of the following activities is an important way to assess the warning signals and predict and imminent volcanic eruption EXCEPT A. consulting volcanic hazard maps B. monitoring earthquake activity C. measuring heat flow D. noting changes in gas and steam emissions
A
The most recently formed portion of any crystal is always found ___. A. on the outer edges B. on whichever side is currently facing upward C. deep within the interior D. there is no consistent pattern for crystal formation
A
The primary evidence that our sun is a third, fourth, or fifth generation star comes from the fact that our ___. A. solar system contains too many heavy elements to have been formed from a first generation nebula B. Sun is too large to be a first generation star C. sun is too hot to be a first generation star D. solar system is too large to be first generation
A
The process of differentiation results in all of the following EXCEPT ____? A. planets forming atmospheres B. rocky material forming in the mantles/crusts of planets C. denser materials becoming concentrated near the cores of planets D. planets becoming approximately spherical
A
The production of magma associated with the addition of carbon dioxide and water to rocks is referred to as A. melting due to an addition of volatiles B. melting due to heat transfer from rising magma C. subduction of volatiles D. decompression melting
A
The single property that can be used to identify any mineral is ___. A. multiple properties must be used to identify a mineral B. luster C. color D. cleavage
A
The texture of a crystalline igneous rock reveals the ___ of the rock. A. cooling history B. chemical composition C. silica content
A
What properties of the source magma lead to the formation of a shield volcano? A. low viscosity and low volatile content B. any magma composition so long as it contains a large portion of dissolved volatiles C. an intermediate composition magma that encounters seawater in the magma chamber D. high viscosity and high volatile content
A
Which environment would most likely produce sedimentary deposits characterized by very well-sorted, very well-rounded grains that are nearly pure quartz? A. beach B. alluvial fan C. river D. glacier
A
Which list properly orders metamorphic rocks from lowest grade to highest grade? A. slate, phyllite, schist, and gneiss B. shale, slate, phyllite, and quartzite C. conglomerate, sandstone, siltstone, and shale D. gneiss, phyllite, schist, and slate
A
Which of the following lists compositions in order of increasing silica content? A. ultramafic, mafic, intermediate, felsic B. mafic, ultramafic, intermediate, felsic C. felsic, intermediate, ultramafic, mafic D. felsic, intermediate, mafic, ultramafic
A
Which of these is NOT a common agent of metamorphism? A. earthquakes B. hydrothermal fluids C. differential stress D. heat
A
Which tectonic/geologic setting is responsible for producing ~70% of the Earth's crust through volcanism? A. mid-ocean ridge B. continental rift C. subduction zone D. oceanic hot spot
A
Most continental topography lies within a range of elevation between ____. A. 2 to 5 km above sea level B. sea level and 1 km above sea level C. sea level and 1 km below sea level D. 3 to 6 km above sea level
B
A buried body of shale is subjected to differential stress, causing clay minerals to realign and produce slate. This is an example of _____. A. diagenesis B. metamorphism C. erosion D. weathering
B
According to the Big Bang Theory, our universe is A. periodically contracting and expanding B. expanding C. contracting D. static
B
As compared to coarse-grained igneous rocks, fine-grained igneous rocks A. solidify at higher temperatures B. cool and solidify more quickly C. cool and solidify more slowly D. solidify at lower temperatures
B
As compared to the rocks that make up the crust, Earth as a whole is ________. A.considerably less dense B. considerably more dense C. about the same density D. slightly less dense
B
If horizontal sedimentary strata overlie tilted strata (and no fault is present), the surface between the horizontal and tilted strata must be a(n) ____. A. conformable sedimentary contact B. angular unconformity C. nonconformity D. disconformity
B
If the relative ages of two formations are known, what else about them can be inferred? A. their lithologies B. their relative position in a sequence of undisturbed rock layers C. their fossil assemblages D. their absolute ages
B
