Geos. 101, Lecture 1 (MWF - Kresan) Review Questions for Exam (Fall 1997) Multiple Choice - Circle the BEST answer. 1. What technique is used to obtain detailed mapping data of the topography of the ocean floor? A. Echo sounding. B. Scuba diving. C. Cable sounding. D. Deep sea drilling. E. Seismic. 2. Seamounts are A. submerged conical submarine volcanoes. B. oceanic islands fringed with coral reefs. C. uplift flat-topped granite plutons. D. submerged flat-topped submarine volcanoes. 3. The youngest rocks of the ocean floors are located A. near spreading ridges. B. in the trenches. C. far from spreading ridges. D. on the abyssal floors. 4. The deep-ocean basins lie at a depth of about A. 50 meters. B. 500 meters. C. 5000 meters. D. 1500 meters. 5. The geological edge of the continents is A. the shoreline. B. the continental shelf. C. the continental slope/rise. D. on the ocean side of the sea-floor trenches. 6. The data that began to be accumulated in the 1950s and would later serve as the basic support for the theory of plate tectonics came mainly from the fields of A. geophysics and oceanography. B. biology and astronomy. C. space tectonology and geochemistry. D. geochemistry and classical physics. 7. Various hypotheses have been developed to account for plate motions. Which of the following processes certainly does not occur? A. Large volumes of intrusive magma exert strong compressional forces at the mid-oceanic ridges, pushing the plates out sideways. B. The mid-oceanic ridges tend to spread out away from the central rifts under the influence of their own weight. C. The descending slabs of cold lithosphere sink beneath the subduction zones under the influence of their own weight. D. All of the above. 8. The significance of the magnetic anomaly patterns discovered in association with the sea floor was that the anomaly patterns A. could be matched with the magnetic reversal chronology to establish an estimated age to the sea floor. B. allowed for the reconstruction of polar wandering paths. C. allowed geomagnetists to reconstruct the super continent Pangea. D. represented absolute proof that the sea floor was spreading apart. 9. The Emperor seamounts and the Hawaiian Islands appear to have formed as the Pacific floor passed over A. an oceanic rise. B. the core. C. a trench. D. a hot spot. 10. Active volcanoes are concentrated A. along zones of tension in the lithosphere. B. along zones of compression in the lithosphere. C. along both zones of tension and compression in the lithosphere. D. where the Earth's crust is very thin. 11. The force of _______________ probably contributes significantly to the movement of the huge crustal plates. A. the tides. B. magnetism. C. gravity. D. convection cells. 12. Lack of active volcanoes in the Himalayas today is consistent with A. the observed lack of a Benioff Zone. B. evidence for great crustal compression. C. the presence of an active orogenic system. D. the observed absence of an active spreading center near the mountains. 13. According to the plate tectonic theory, the San Andreas fault is a A. convergence zone. B. subduction zone. C. transform fault. D. triple junction. 14. Nearly all of the water in the hydrologic cycle resides in A. lakes. B. the atmosphere. C. the ground. D. the oceans. 15. Which of the following materials would produce the most groundwater? A. Unfractured limestone. B. Unfractured basalt. C. Unfractured granite. D. Highly fractured sandstone. 16. A perched water table is most likely to develop on top of A. shale. B. sandstone. C. gravel. D. fractured granite. 17. Springs can be found at all the following locations except A. faults. B. cave mouths. C. where joints intersect the land surface. D. on dry streambeds. E. along the top surface of impermeable rock layers. 18. An icicle-like deposit hanging from the roof of a cavern is a A. stalactite. B. geyserite. C. stalagmite. D. silicate. 19. Which of the following factors tends to delay the build up of the discharge of surface streams after a storm? A. Extensive heavy vegetation. B. Low permeability of surface rocks. C. High topographic relief. D. Extensive urban development. 20. An artesian well will flow if the A. top of the well is at a lower elevation than that of the water table in the recharge area. B. top of the well is at a higher elevation than that of the water table in the recharge area. C. bottom of the well is at a lower elevation than that of the land surface in the recharge area. D. bottom of the well is at a lower elevation than that of the water table in the recharge area. 21. Which materials would make the best aquifer: A. Clay and silt. B. Gravel and sand. C. Unfractured granite. D. Sandstone. E. Limestone. 22. Which of the following would make the best aquifer? Porosity Permeability A. Rock A 5% high B. Rock B 10% medium C. Rock C 30% low D. Rock D 35% medium E. Rock E 50% low 23. A well is most likely to encounter a good supply of water at shallow depth in which situation? A. In granite on a ridge top. B. In a shale in a valley bottom. C. In sandstone on a ridge top. D. In sandstone in a valley bottom. E. None of the above. 24. A sand or gravel deposit on the inside of a meander is a A. levee. B. channel bar. C. flood plain. D. point bar. 25. If the base level of a stream is lowered A. the stream will deposit to raise the base level to its former position. B. the stream will begin to downcut at its headwaters. C. the stream will begin to downcut at its downstream end, and downcutting will progress upstream until the stream channel is graded with the new base level. D. a change in base level will have no effect on the stream. 26. Roads on hillsides tend to become unstable if they are built on A. concrete pillars. B. sedimentary layers that slope back into the hillside. C. an area that has been excavated into a hillside. D. bedrock such as granite. E. sedimentary layers that slope parallel to the hillside. 27. Which of the following would be most effective in stabilizing an active landslide? A. Cutting away the toe of the landslide deposit. B. Saturating the landslide deposit with water. C. Draining the water out of and away from the landslide area. D. Piling additional rock and soil on the landslide near the breakaway scarp. 28. California homeowners saved from the recent wild fires are not "home-free." The rainy season is about to begin and the next problem they will face is A. increased potential for mud and debris flows. B. accelerated soil erosion. C. flash floods. D. all of the above. E. none of the above. 29. All of the following can cause deserts except A. rising air. B. rain shadow. C. great distance from the ocean. D. descending air. E. proximity to cold ocean currents. 30. A wind-deposited material composed mainly of silt, with some clay and fine sand, is A. firn. B. till. C. loess. D. tuff. 31. Along the equator there is a belt of A. highly variable pressure. B. unpredictable pressure. C. high pressure. D. low pressure. 32. A barchan is a A. crescent-shaped dune, with its horns anchored by vegetation. B. crescent-shaped dune, with its horns pointing downwind. C. dune in which the cross beds dip in an upwind direction. D. long linear dune. 33. You are lost in dense fog along a coastline. If you could get to the beach, you could find your way back. The one really neat part of the hike is the crescent shaped dunes which hug rather deep depressions. You realize that theses are parabolic or blow-out dunes. The tapered arms of the dunes point south. There is no wind today but you suddenly remember that in this region strong, gusty winds usually come off the ocean across the coastal plain. In what direction do you now head? A. North. B. South. C. East. D. West. E. Northwest. 34. A common topographic feature of the Basin and Range Province formed at the base of mountains by the coalescence of several alluvial fans is the A. pediment. B. playa. C. bajada. 35. The Basin and Range province, which is characterized by flat valley floors bounded by steep mountain ranges, covers most of this state in the U.S. A. New Mexico. B. Arizona. C. Nevada. Discussion Questions - Answer the following discussion questions. Be as complete as possible. Illustrate your answers with diagrams or sketches. 1. Discuss three ways water enhances the potential for mass movement. Your answer must include the single most important effect of water. 2. You are about to purchase a hillside lot for use as a homesite. Discuss three lines of evidence that would indicate the property was susceptible to mass movement. Be sure you illustrate each in a diagram and include in your discussion how each is indicative of an area with unstable slopes. 3. Twenty years ago a family built a home adjacent to a small desert wash. In fact, they used the sandy bottom as a driveway and enjoyed the lush vegetation along its banks. Last year a large shopping center with many acres of paved parking lot was built upstream from this family's home. Exploring their wash, the kids walked right into the parking lot. What impact might this recent development have on their home? Discuss at least TWO. 4. Your parents have just purchased a summer home on the narrow floodplain of a small dry wash in the bottom of a beautiful canyon in northern Arizona. The sedimentary rocks in the canyon walls are all horizontal. In a neat, well-labeled diagram illustrating the setting described above, also show the following: a) a spring in the cliff due to a perched water table; b) the likely area of recharge for the regional aquifer; c) the position of the regional water table; d) a likely location and depth of a well which will dependably produce a relatively large amount of water so that your parents can irrigate the surrounding floodplain for an extensive vegetable garden. 5. Of the several factors that contribute to producing desert conditions name and describe the operation of two. For each of the factors you have described, give an example of a desert region where that factor is important. 6. Using a diagram, show how the common occurrence of deserts near 30¡N and 30¡S of the equator is related to global climatic circulation. What other causes of desert conditions can you state? 7. Why do streams continue to flow in some areas many weeks after precipitation has taken place in their watershed? Be complete with your answer. Use a diagram to illustrate your discussion. 8. In his keynote address, "A Reverence for Rivers," Luna Leopold characterized a river as being "like an organism; it is internally self-adjusting." Explain what Leopold meant. Illustrate your discussion with an example and a flow chart or diagram. 9. Historically in Tucson landfills for waste were located near the rivers, especially the Santa Cruz where land was cheap and the dump was close to major roads and the city. Discuss why this location may not be a good idea. Use a diagram to illustrate your answer. 10. Characterize one type of active crustal plate boundary. For full credit your answer must include the following: A. Neat, well-labeled illustration of the active boundary. B. A discussion of the following characteristics: - magma types - volcanic activity - earthquake foci and magnitude - type of stress and style of deformation - long-term geologic consequences of the processes acting at this plate boundary