Earth: An Introduction to Physical Geology 12th Edition Test Bank

Exam Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which scientist developed the idea of continental drift? 1) _______ A) Charles Darwin B) Alfred Wegener C) Albert Einstein D) Isaac Newton 2) Which war was indirectly responsible for the development of the tools that made the theory of plate tectonics possible? A) Korean War B) Vietnam War C) World War I D) World War II 2) _______ 3) What is the name of the supercontinent proposed by Alfred Wegener? A) Rodinia B) Pangaea C) Nuna 3) _______ D) Amasia 4) Although the jigsaw-puzzle fit of the southern continents was noted, opponents of continental drift argued that, even if continental displacement had occurred, a good fit between the continents today would be unlikely. What geologic evidence did they cite to support this claim? A) The tensional stress of splitting sheared the continents beyond all repair. B) Deposition in river deltas had changed the longshore current, resulting in erosion. C) Wave erosion and coastal deposition have changed the shape of the continents. D) Fissure eruptions along continental margins had created new land. 4) _______ 5) Even before the proposal of continental drift, paleontologists recognized that some sort of land connection was needed to account for the identical fossil organisms found on multiple continents. Select the correct hypothesis or hypotheses these paleontologists developed. A) Island stepping stones, transoceanic land bridge, and floating debris used for rafts B) Sea level falling C) A transoceanic land bridge D) A chain of island stepping stones E) Floating debris used as rafts and sea level rising 5) _______ 6) When the continents were assembled and mountain ranges were matched up, mountains in Scandinavia and the British Isles matched up perfectly with which North American mountain range? A) Olympic Mountains B) Rocky Mountains C) Sierra Nevada Mountains D) Appalachian Mountains 6) _______ 7) When considering evidence of glaciation on the southern continents, why did Wegener reject the explanation that the entire planet had experienced a period of extreme cooling? A) Because the 16O/18O ratios in fossils supported an ice-free period 7) _______ B) Because he knew the “glacial debris” was actually a misinterpreted landslide C) Because the glacial debris was localized to a few small mountain valleys D) Because geologic evidence supported the existence of tropical swamps in the Northern Hemisphere 8) In which decade was the theory of plate tectonics developed? A) 1990s B) 1940s C) 1960s 8) _______ D) 1970s 9) In the mid-twentieth century, researchers dredging the seafloor could not find any materials older than ________. A) 1.5 billion years B) 10,000 years 9) _______ C) 1.2 million years D) 180 million years 10) Which of the following is not one of the major tectonic plates on the Earth’s surface? A) Pacific Plate B) Juan de Fuca Plate C) African Plate D) North American Plate 10) ______ 11) The lithosphere is composed of the ________ and the rigid part of the ________. A) crust; lower mantle B) outer core; inner core C) crust; upper mantle D) mantle; outer core 11) ______ 12) Which type of plate boundary accounts for the smallest percentage of all plate boundaries on the surface of the Earth? A) Divergent boundaries B) Transform boundaries C) Convergent boundaries 12) ______ 13) Continental crust is mainly composed of ________, whereas oceanic crust is mainly composed of ________. A) olivine; basalt B) limestone; gabbro C) gabbro; granite D) granite; basalt 13) ______ 14) Why are the mid-ocean ridges higher in elevation than the surrounding ocean floor? A) Warmer material near the ridge is less dense, so it is more buoyant on the mantle. B) Thermal springs developing in stress fractures are depositing large volumes of material, increasing the height. C) The force of magma extruding from the fissure pushes the seafloor up. D) The collision of the tectonic plates is forcing material higher. 14) ______ 15) Continental rifting is occurring today in ________. A) western California (San Andreas Fault) B) Ethiopia and Kenya (East African Rift valley) C) the Pacific Northwest (Cascadia subduction zone) D) between Minnesota and Wisconsin (mid-continent rift) 15) ______ 16) At a ________, an oceanic plate will be forced beneath another plate because of differences in density. A) subduction zone B) collision zone C) transform boundary D) continental rift 16) ______ 17) Think about what happens to the density of an oceanic plate as it ages and cools. How will the age and temperature of the subducting plate affect its angle of descent? A) Young, warm plates will have a shallow angle of descent. B) Old, cool plates will have a shallow angle of descent. C) Old, warm plates will have a steeper angle of descent. D) Young, cool plates will have a steeper angle of descent. 17) ______ 18) A ________ is a geographic low, which marks the location where oceanic lithosphere descends into the mantle. A) deep-ocean trench B) fold and thrust mountain C) seismic zone D) mid-ocean rift 18) ______ 19) Which type of convergence will result in a continental volcanic arc? A) Continental-continental B) Oceanic-continental 19) ______ C) Oceanic-oceanic 20) Which type of convergence will result in a volcanic island arc? A) Oceanic-oceanic B) Continental-continental 20) ______ C) Oceanic-continental 21) Where are the majority of transform faults located? A) Radiating from convergent boundaries as stress fractures B) Southern California C) On the ocean floor offsetting segments of oceanic ridge D) Along mountain ranges that have been thrust up due to collision 21) ______ 22) What is a mantle plume? A) An upwelling of hot material from the Earth’s interior that is cylindrical in shape B) Material rising up from a subducting plate going through partial melting C) A form of batholith composed of ferromagnesian materials D) The magma that rises up from the mantle at a divergent plate boundary 22) ______ 23) ________ occurs when magnetic minerals in lavas align their magnetic fields with magnetic north, preserving a record of that pole’s location at that moment in time. A) A mantle plume B) Seafloor spreading C) Magnetic reversal D) Paleomagnetism 23) ______ 24) A typical rate of seafloor spreading in the Atlantic Ocean is ________. A) 2 centimeters per year B) 20 feet per year C) 0.1 inches per year D) 2 meters per year 24) ______ 25) All of the following offer additional evidence supporting the theory of plate tectonics except for ________. A) measurements of plate motions B) changes in the Moon’s orbit due to shifting plates C) hot spots D) ocean floor sediment cores 25) ______ 26) Where is the top of the asthenosphere closest to Earth’s surface? A) Along a transform fault B) Along a mid-ocean ridge C) Above a deep mantle plume D) Along a subduction zone 26) ______ 27) Which of the following statements best describes the tectonic setting for Mount St. Helens and the other Cascade volcanoes? A) Old, deeply eroded volcanoes built before the Pacific Ocean existed B) Young, deeply eroded, basaltic volcanoes built when western North America was over the present-day site of the Hawaiian hot spot C) A chain of young, active volcanoes built on a continental margin above a sinking slab of oceanic lithosphere D) A chain of old, inactive volcanoes built while western North America moved over a mantle plume 27) ______ 28) How did researchers in the mid-twentieth century obtain ocean floor samples in order to determine the age of the seafloor? A) Satellite imagine images B) Hydraulic vacuum tubes C) Drilling ships D) Deep-diving manned submersibles 28) ______ 29) Samples from the seafloor around the Mid-Atlantic Ridge and the East Pacific Rise show that both areas have been creating new material in the last five million years. Samples from the East Paci Rise fic show the 29) five-milli on-yearold seafloor is three times as wide as similarly aged material from the Mid-Atla ntic Ridge. What does this say about the rate of seafloor spreadin g in the East Pacific? A) The seafloor at the Mid-Atlantic is growing more slowly. B) The seafloor at the Mid-Atlantic is growing more quickly. C) The seafloor at the East Pacific Rise is growing more slowly. D) The seafloor at both sites is growing at the same rate. ___ ___ 30) What two pieces of information would researchers need to have in order to calculate the rate of plate motion for seafloor spreading? A) Distance from the rift and age of seafloor sample B) Age of the seafloor sample and age of the continent C) Age of the continent and depth of the water D) Type of rock and distance from the rift 30) ______ 31) How can GPS receivers and satellites be used to monitor plate motion? A) Satellites send lasers to measure the distance to continents. B) Satellites track seafloor spreading. C) GPS receivers send signals to each other to see if the units are getting closer together. D) GPS receivers are placed on landmasses to track their locations. 31) ______ 32) How can the orientation of transform faults provide information about the direction of plate motion? A) Transform faults are parallel to the direction of plate motion. B) Transform faults are oriented perpendicular to the direction of plate motion. C) Transform faults are parallel to convergent boundaries. D) Transform faults radiate out from the rift zone located in the center. 32) ______ 33) Which is denser: a 100-million-year-old oceanic lithosphere near a convergent boundary, a 15-million-year-old oceanic lithosphere near a rift, or the upper part of the asthenosphere? 33) ______ A) A 15-million-year-old oceanic lithosphere B) Upper asthenosphere C) 100-million-year-old oceanic lithosphere D) They all have the same density. 34) What generates the heat necessary for convection in the Earth? A) Chemical reactions between geologic materials and hydrothermal fluids B) Friction between moving slabs C) Decay of radioactive materials D) Volcanic eruptions 34) ______ 35) What is slab pull? A) Warmer oceanic lithosphere is pulled below colder asthenosphere. B) Cold continental lithosphere is pulled below warmer asthenosphere. C) Cold oceanic lithosphere is pulled below warmer asthenosphere. D) Cold continental lithosphere is pulled below warmer oceanic lithosphere. 35) ______ 36) Along which tectonic boundary is ridge push going to be most important in helping to drive plate motion? A) Divergent boundary B) Convergent boundary C) Transform boundary 36) ______ 37) Which factor contributes the most toward plate motion at a convergent boundary? A) Ridge push B) Mantle drag C) Friction D) Slab pull 37) ______ 38) In which layer of the Earth does the convection necessary for plate motion occur? A) Outer core B) Mantle C) Crust D) Inner core 38) ______ 39) Which model of convection describes how the interior is divided into several levels of convection cells? A) Differentiation model B) Plume model C) Layer cake model D) Whole-mantle convection 39) ______ 40) In the whole-mantle convection model, what feature balances the deeply descending lithosphere by transporting hot material toward the surface? A) Mantle plumes B) Rift zones C) Decompression melting D) Kimberlites 40) ______ 41) During what time period did scientists first notice the jigsaw puzzle fit of the southern continents? A) 1600s B) 1910s C) 1800s D) 1750s 41) ______ 42) Which of the following best explains the global distribution of plant species, such as the Glossopteris, during the Mesozoic? A) Seeds were ingested by animals and later deposited in scat. B) Seeds were small, so they could be carried by the wind. C) The landmasses were joined and the plant had a large geographic extent. D) Oceans that transgressed on the continents carried the seeds to different locations. 42) ______ 43) Where is oceanic lithosphere thickest and why? A) In the middle of the tectonic plate as it has not been scraped off during subduction B) Close to the subduction zone boundary because continental material is added to it C) Furthest from the spreading center because the older oceanic crust is cooler 43) ______ D) Along oceanic ridges because it is newest there 44) The lithosphere is broken into ________ major plates and many minor plates. A) nine B) seven C) fifteen D) twelve 44) ______ 45) Which of the following statements regarding the global oceanic ridge system is correct? A) The ridge system has an extensive submarine canyon system. B) The ridge system marks the locations of most mantle plumes in the mantle. C) The ridge system marks the deepest locations on the Earth’s surface. D) The ridge system is the longest topographic feature on the Earth’s surface. 45) ______ 46) Another name for a ________ boundary is a destructive boundary. A) divergent B) convergent 46) ______ C) transform 47) Which of the following makes it possible for oceanic crust created at divergent boundaries to be carried to the sites of destruction at convergent boundaries? A) Magma plutons weighing the crust down at convergent boundaries, pulling the slab B) Alignment of magnetic fields in iron particles C) Seawater seeping into plate fractures to lubricate the rocks D) Transform boundaries that accommodate plate motion 47) ______ 48) Which of the following plate boundaries is not usually associated with volcanism? A) Convergent B) Transform C) Divergent 48) ______ 49) A convergent boundary is usually associated with which physical features? A) Volcanic arcs and submarine trenches B) Submarine trenches C) Rift valleys D) Horizontally displaced rocks E) Volcanic arcs 49) ______ 50) Which two continents did Wegener cite as having the best evidence of a close coastline fit? A) North America and Europe B) South America and Africa C) India and Asia D) Europe and Africa 50) ______ 51) The ________ is a hotter, weaker region in the mantle that lies below the lithosphere and responds to forces by flowing. A) atmosphere B) inner core C) outer core D) crust E) asthenosphere 51) ______ 52) Which is least dense? A) Continental lithosphere C) Asthenosphere 52) ______ B) Mantle D) Oceanic lithosphere 53) ________ is the name of the process by which new seafloor is generated at mid-ocean ridges. A) Melting B) Seafloor spreading C) Convection D) Subduction 53) ______ 54) ________ and ________ drive water from the pores of a subducted oceanic plate, which leads to partial melting. 54) ___ ___ A) Air; heat C) Heat; pressure B) Salt; oil D) Compression; tension 55) Lava solidifying during a period of reverse polarity will align the magnetic fields of its iron particles toward the ________ pole. A) South B) West C) North D) East TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false. 56) The majority of divergent plate boundaries are associated with oceanic ridges. 55) ______ 56) ______ 57) Subduction zones will only develop between a continental plate and an oceanic plate. 57) ______ 58) An oceanic plate that has been permeated by water before subduction will trigger melting sooner than a “dry” oceanic plate. 58) ______ 59) The magnetic poles roughly correspond to the locations of the geographic poles. 59) ______ MATCHING. Choose the item in column 2 that best matches each item in column 1. Match the tectonic boundary with its direction of motion. 60) Convergent boundary A) Two plates move toward each other 60) ______ 61) Divergent boundary B) Two plates slide past each other 61) ______ 62) Transform boundary C) Two plates pull apart from each other 62) ______ 63) Convergent boundary A) Crust is being destroyed 63) ______ 64) Divergent boundary B) Crust is being conserved 64) ______ 65) Transform boundary C) Crust is being created 65) ______ Match the tectonic boundary with the effect on the crust. Match the tectonic boundary with the type of stress affecting it. 66) Convergent boundary A) Tension 66) ______ 67) Divergent boundary B) Shear 67) ______ 68) Transform boundary C) Compression 68) ______ Match the convergent boundary with a real-world example. 69) Oceanic-continental A) Pacific and Philippine plates 69) ______ 70) Oceanic-oceanic B) North American and Juan de Fuca plates 70) ______ 71) Continental-continental C) Indian and Eurasian P=plates 71) ______ ESSAY. Write your answer in the space provided or on a separate sheet of paper. 72) Explain how geologists regarded the positions of the ocean basins and the continents prior to the advent of plate tectonics and how that perspective differs from how modern geologists regard those same features. 73) When continental drift was first proposed in 1912, geologists from one specific continent strongly opposed the idea. Which continent’s geologists were against the idea, and why did they have difficulty accepting it? (Think about where the evidence for continental drift is very clear.) 74) The acceptance of plate tectonics after the initial rejection of continental drift has been described as a scientific revolution. Explain why plate tectonics was so revolutionary and what tools were used to bring it about. 75) Scientific research supports the existence of Alfred Wegener’s proposed supercontinent, Pangaea, approximately 300 million years ago. Pangaea subsequently broke apart, and the piecesour modern continentsmigrated to the positions they occupy today. Based on your knowledge of the mechanics of tectonic motion, do you think there is a likelihood of another supercontinent forming? If so, where? 76) Why would using the continental shelves to reassemble the continents provide a better fit than using the shorelines of the continents? 77) Mesosaurus is a small freshwater reptile that existed in the Permian Period. It is only found in black shale deposits in eastern South America and southwestern Africa. If the Mesosaurus is an aquatic reptile and the continents are currently separated by an ocean, evaluate why the Mesosaurus would be used as strong evidence in favor of continental drift rather than as evidence against it. 78) Which two aspects of continental drift were most objectionable to scientists of the early twentieth century? Why? 79) Explain how the shapes of polar wandering paths for Europe and North America and the locations of those continents can be used to support the existence of Pangaea. 80) Lava lamps are commonly used to illustrate how convection cells in the mantle convey heat from the core to the exterior of the Earth. Explain how convection works, using a lava lamp as a proxy for the Earth. 81) Alfred Wegener provided several pieces of evidence supporting the idea that the planet’s continents were once joined in a single landmass. List three of them. 82) How does the temperature of the lithosphere and that of the asthenosphere affect those layers’ rigidities and responses when force is applied? 83) There is an expression in American society that it would only take one good earthquake and the state of California would sink into the ocean. Using what you know about plate boundaries, evaluate this statement. 84) If there is no compositional difference between two oceanic plates, what other factor will determine which plate will become the subducted one and why? (What other factor can control density?) 85) If new plate material is being created at divergent plate boundaries, is the Earth growing larger? Explain why or why not. MATCHING. Choose the item in column 2 that best matches each item in column 1. Using the map provided, locate three continental plates and three oceanic plates. Match the correct label with the correct plate. 86) Pacific Plate A) Oceanic Plate 86) ______ 87) North American Plate B) Continental Plate 87) ______ 88) Nazca Plate 88) ______ 89) Philippine Plate 89) ______ 90) Eurasian Plate 90) ______ 91) African Plate 91) ______ ESSAY. Write your answer in the space provided or on a separate sheet of paper. 92) Using the block diagram provided, explain how new plate material is created at a divergent plate boundary. Make sure your answer includes a discussion on the forces at work and the generation of magma beneath the rift. MATCHING. Choose the item in column 2 that best matches each item in column 1. Match the oceanic and continental lithospheres with their positions on the figure below. 93) Oceanic Plate A) on the left 93) ______ 94) Continental Plate B) on the right 94) ______ Using the figure above, indicate which boundaries are convergent, divergent, and transform. 95) Pacific/North American boundary A) Divergent 95) ______ 96) Nazca/South American boundary B) Transform 96) ______ 97) Pacific/Antarctic boundary C) Convergent 97) ______ 98) African/South American boundary 98) ______ 99) Caribbean/North American boundary 99) ______ 100) African/Eurasian boundary 100) _____ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 101) 101) _____ The Hawaiian mantle plume has left a chain of volcanic islands and seamounts stretching back for ~70 million years. Although the mantle plume has remained relatively stationary, the Pacific plate above it has moved. Use the figure to answer the following question. What direction was the Pacific plate moving between 65 and 43 million years ago? A) Northwes B) North C) West D) Southeast E) East t 102) y, the Pacific Plate above it has moved. Use the figure below to answer the following question. What direction has the Pacific plate been moving for the last 40 million years? The Hawaiia n mantle plume has left a chain of volcanic islands and seamoun ts stretchin g back for ~70 million years. Althoug h the mantle plume has remaine d relatively stationar 102) _____ A) North B) Northwes t C) Northeast D) Southeast E) West 103) 103) _____ The Hawaiian mantle plume is a classic example of a long-lived mantle plume being used to demonstrate how the motion of a tectonic plate has changed over time. Which hot spot would be an even better indicator of the Pacific plate’s motion over time? A) Cape Verde mantle plume B) Yellowstone C) Easter Island D) Pitcairn E) Caroline 104) volcano to be forming? As the island of Hawaii continue s to move away from the mantle plume, a new submari ne volcano will be created. Off which coast would you expect the new submari ne 104) _____ A) Southeast coast C) Southwest coast B) North coast D) Northeast coast 1) B 2) D 3) B 4) C 5) A 6) D 7) D 8) C 9) D 10) B 11) C 12) B 13) D 14) A 15) B 16) A 17) B 18) A 19) B 20) C 21) C 22) A 23) D 24) A 25) B 26) B 27) C 28) C 29) A 30) A 31) C 32) A 33) C 34) C 35) C 36) A 37) D 38) B 39) C 40) A 41) A 42) C 43) C 44) C 45) D 46) B 47) D 48) B 49) A 50) B 51) E 52) A 53) B 54) C 55) A 56) TRUE 57) FALSE 58) TRUE 59) TRUE 60) A 61) C 62) B 63) A 64) C 65) B 66) C 67) A 68) B 69) B 70) A 71) C 72) Prior to the 1960s, geologists viewed the ocean basins and continents as fixed features: they neither grew nor moved. They also believed both were incredibly old. However, after the development of the theory of plate tectonics in the 1960s, geologists realized that the continents do migrate across the globe, a process that changes the size and shape of the ocean basins. As a result, some ocean basins are much younger than was previously believed. 73) Geologists from North America were strongly against the idea of continental drift. Part of the reason behind their reluctance was that the strongest evidence to support it was found in the southern continents (Africa, South America, and Australia), the geology of which was not as well known to North American scientists. 74) Scientists initially held onto the belief that the continents and ocean basins were fixed objects, both of which dated back to the earliest days of the Earth. When continental drift was proposed, which challenged this belief, scientists had difficulty accepting it because the evidence was not as clear outside the southern continents. After World War II, modern tools like sonar, ocean drilling, and magnetometers were used to gather evidence about the age and bathymetry of the seafloor. This evidence (seafloor spreading and paleomagnetism) was used to support continental drift and develop the modern theory of plate tectonics. 75) The break-up of Pangaea led to the creation of the Atlantic Ocean. The divergent plate boundary that exists today is still spreading, enlarging the basin and pushing North America, South America, Europe, and Africa farther apart. As this basin grows, the Pacific Ocean basin shrinks due to the convergent plate boundaries around the margins of the Pacific plate. Recent studies indicate that the North American and Eurasian continents will meet over the North Pole (http://www.nature.com/nature/journal/v482/n7384/full/nature10800.html), though it would be reasonable for students to suggest that the next supercontinent would form in the Northern Pacific. 76) The shorelines are continuously eroded by waves or are being built out by longshore currents, fluvial deposition, and so on. These processes change the shapes of the continents over time. The continental shelves are currently several hundred feet below the erosive power of the waves, so they are left relatively untouched. 77) First, Mesosaurus is a freshwater reptile. It would not have been able to survive the trip across the southern Atlantic Ocean. Second, if it were able to swim such great distances as to be able to cross an ocean, it would be reasonable to assume Mesosaurus remains would be more widespread. 78) – Mechanism for continental drift: Wegener proposed that gravitational forces from the Sun and Moon that produce tides could gradually move the continents. However, if those forces were strong enough to move continents, the Earth’s rotation would also have ceased. – Continental rocks versus oceanic rocks: Wegener proposed that the continental landmasses broke through the thinner oceanic crust like an ice breaker. However, there was no evidence at the time to suggest such a feat was possible without severe deformation of the continents. 79) For the first 300 million years, the polar wandering paths for both continents were similar in shape and direction to the were separated by several thousand miles. Starting in the middle of the Mesozoic, both paths began to converge on pole the North Pole. If these two continents are joined, these polar wandering paths overlap, supporting a unified but supercontinent. 80) The bulb at the base of the lamp warms the wax in the lamp. The thermal energy from the absorbed heat causes the atoms of the wax to move farther apart, making the wax less dense and allowing it to rise. Once at the top, the wax begins to cool, losing thermal energy. The atoms of wax move closer together, making the wax denser and forcing it to sink. Once the wax gets near the bulb again, it begins to warm again and the process starts all over. 81) Answers will vary but can include any three of the following: – Jigsaw puzzle fit of the southern continents – Matching fossils of multiple continents – Matching mountain ranges across multiple continents – Matching rock types across multiple continents – Matching glacial debris on multiple continents 82) The lithosphere is cooler and more rigid, so will bend or break when force is applied. The asthenosphere is warmer and more pliable, so will flow when force is applied. 83) The largest plate boundary in California is a transform boundary, which primarily moves horizontally, not vertically. 84) Temperature, which is a function of age. – Colder plates are denser and therefore will become the subducted plate. 85) No. The Earth is remaining the same size because although new plate material is being created, old plate material is being destroyed at convergent boundaries. 86) A 87) B 88) A 89) A 90) B 91) B 92) Tensional stress pulls the plates apart, creating a rift between them. The creation of the rift means that there is not as much force (the weight of the overlying plates) pushing down on that part of the mantle, which results in decompression melting that generates magma. Magma is less dense than the surrounding rock and rises up, filling the gap between the two plates. However, the plates are still being pulled apart, so the new material is also pulled apart, with part of it adhering to each plate. 93) A 94) B 95) C 96) C 97) A 98) A 99) B 100) B 101) B 102) B 103) D 104) A