Give it Some Thought Questions

The formula for the volume of a cone is V = ⅓ πr2 (where V = volume, π = 3.14, r = radius, and h = height). If Mauna Loa is 9 kilometers high and has a radius of roughly 85 kilometers, what is its approximate total volume?

(1/3) x 3.14 x (85)2 x 9km= 68059.5

Density is a key component in the behavior of Earth materials and is essential to understanding important aspects of the plate tectonics model. Describe three different ways that density and/or density differences play a role in plate tectonics.

1) The subduction of more dense oceanic crust underneath continental crust; 2)The rising of hotter mantle material at divergent boundaries and the sinking of colder lithospheric plates at subduction zones, thus creating the "conveyor belt" model that somehow drives the plate tectonics engine. 3)The collision and uplift of continental crust at continental to continent convergent boundaries due to lower densities of continental rocks.

For each of the volcanoes or volcanic regions listed below, identify whether it is associated with a convergent or divergent plate boundary or with intraplate volcanism. 1) Crater Lake 2) Hawaii's Kilauea 3) Mount St. Helens 4) East African Rift 5) Yellowstone 6) Mount Pelée 7) Deccan Traps 8) Fujiyama

1) convergent plate 2) Intraplate volcanism 3) convergent plate 4) divergent plate 5) Intraplate volcano 6) convergent plate 7)intraplate volcano 8) convergent plate

What does the Vishnu Schist tell you about the history of the Grand Canyon prior to the formation of the canyon itself?

1) formation of Vishu schist 2)deposition of sedimentary layers found above the vishnu schist 3)Carving of the canyon by the Colorado River

Which of the three types of plate boundaries is primarily associated with normal faulting? Thrust faulting? Strike-slip faulting?

1. divergent boundaries= normal faulting 2. convergent boundary= Thrust faulting 3. Transform plate boundary= strike-slip faulting

Earthquakes below the Yellowstone caldera originate at very shallow depths, about 4 kilometers on average. Below this depth, the rocks are at about 400°C, too hot and weak to store elastic energy. Based on this data, answer the following questions: Calculate the average geothermal gradient in the first 4 kilometers beneath the Yellowstone caldera, assuming an average surface temperature of 0°C (32°F) and a temperature at 4 kilometers of 400°C (752°F). (For this example, the geothermal gradient, which is the increase in temperature with depth, should be measured in degrees centigrade per 100 meters.) At about what depth is the groundwater below the Yellowstone caldera hot enough to "boil" and therefore capable of generating a geyser?

20? 2.1?

Gold has a specific gravity of almost 20. A 5-gallon bucket of water weighs 40 pounds. How much would a 5-gallon bucket of gold weigh?

800 pounds 40lbs x 20= 800

Briefly describe the major differences between the evolution of the Appalachian Mountains and the North American Cordillera.

A Cordilleran-type orogeny, named after the North American Cordillera, is associated with a Pacific-like ocean—in that, unlike the Atlantic, the Pacific may never close. The rapid rate of seafloor spreading in the Pacific basin is balanced by a high rate of subduction. In this setting, island arcs and small crustal fragments are often carried along until they collide with an active continental margin and accrete (join) onto it. Alpine-type orogenies are episodes of mountain building that occur where two continental masses collide. They are named after the Alps, which have been intensively studied for more than 200 years. Mountain belts formed by the closure of major ocean basins include the Himalayas, Appalachians, Urals, and Alps. Continental collisions result in the development of mountains characterized by laterally shortened and vertically thickened crust, achieved through deformation such as folding and large-scale thrust faulting. Prior to the collision of the two large landmasses, this type of orogeny may also involve the accretion of smaller continental fragments or island arcs that occupied the ocean basin that once separated the two continental blocks. note: Detailed studies of the Appalachians indicate that this mountain belt was the result of three distinct episodes of mountain building.

Using the map of global soil regions in Figure 8.17, identify the main soil order in the region adjacent to South America's Amazon River (point A on the map) and the predominant soil order in the American Southwest (point B). Briefly contrast these soils. Do they have anything in common? Referring to Table 8.2 might be helpful.

A is Oxisols and B is Aridisols. Oxisols would form on old land surfaces unless parent material were strongly weathered before they were deposited. On the other hand, Aridisols are soils that develop in dry places with insufficient water to remove soluble minerals. Both of them are not effective for cultivation

For each of the accompanying four sketches, identify the geologic setting (zone of volcanism). Which of these settings will most likely generate explosive eruptions? Which will produce outpourings of fluid basaltic lavas?

A would generate explosive eruptions because of the oceanic-continental convergence, while D would produce fluid basaltic lavas because shield volcanoes are formed from intraplate volcanism, which triggers hot spots.

Do an Internet search to determine which minerals are used to manufacture the following products: A.Stainless steel utensils B.Cat litter C.Tums brand antacid tablets D.Lithium batteries E. Aluminum beverage cans

A. Chromium B. bentonite clay C. Calcium Carbonate D. Lithium, cobalt, and nickel E. Bauxite

Each of the following statements describes a silicate mineral or mineral group. In each case, provide the appropriate name: A. The most common member of the amphibole group. B. The most common light-colored member of the mica family C. The only common silicate mineral made entirely of silicon and oxygen D. A silicate mineral with a name based on its color E. A silicate mineral characterized by striations F. Silicate minerals that originate as a product of chemical weathering

A. Hornblende B. Muscovite C. Quartz D. Olivine E. Plagioclase feldspars F. Clay Minerals

The accompanying image shows a geologist at the end of an unconsolidated flow consisting of lightweight lava blocks that rapidly descended the flank of Mount St. Helens. a.What term best describes this type of flow: an aa flow, a pahoehoe flow, or a pyroclastic flow? b.What lightweight (vesicular) igneous rock type is likely the main constituent of this flow?

A. Pyroclastic flow b. Pumice

Apply your understanding of igneous rock textures to describe the cooling history of each of the igneous rocks labeled A-D.

A. is a fine-grained igneous rock (Rhyolite) which has seen a rapid rate of cooling resulted in microscopic crystals and voids. B. is a porphyritic igneous rock (Granite porphyry) meaning a very slow rate of cooling followed by a more rapid period of cooling, resulting in a mixture of large and small crystals, respectively. C. Is a coarse-grained igneous rock (Granite), so it had a relatively slow, steady rate of cooling magma chambers, resulting in visible crystals to form. D. is a vesicular igneous rock (Pumice) meaning that it formed on the upper levels of lava and cooled rapidly enough for the openings made by gas bubbles to be preserved

This soil sample is from a farm in the Midwest. From which horizon was the sample most likely taken—A, E, B, or C? Explain.

A? because of it's dark color and resembles mineral matter mixed with some humus?

What factors influence how much rain will soak into the ground compared to how much will run off?

Amount of rainfall and the timespan of the rainfall

Suppose that a sliver of oceanic crust were discovered in the interior of a continent. Would this refute the theory of plate tectonics? Explain.

An oceanic-crust sliver in the interior part of a continent does raise a substantive problem as to its origin. As part of the overall plate tectonic theory, slices and slivers of oceanic crust are known to be accreted to continental margins at subduction zones. Oceanic crust terranes accreted in pre-Mesozoic time could be "positioned" more toward a continental interior if a sizable continental terrane was accreted during a later collisional event, leaving the oceanic-crust sliver surrounded by continental crust. Thus a continental interior, oceanic crust sliver can be explained in terms of continental accretion and the plate tectonic theory. Older ideas on the origin of exotic, continental interior terranes are contrived and unconvincing.

Which of the accompanying sketches best illustrates an Andean-type orogeny, a Cordilleran-type orogeny, and an Alpine-type orogeny?

Andean-type orogeny is B, Cordilleran-type orogeny is C, and an Alphine-type orogeny is A

During a trip to the grocery store, your friend wants to buy some bottled water. Some brands promote the fact that their product is artesian. Other brands boast that their water comes from a spring. Your friend asks, "Is artesian water or spring water necessarily better than water from other sources?" How would you answer?

Artesian water, spring water, and tap water come from aquifers and have practically the same quality.

One of the photos below shows an outcrop of metamorphic rock; the other two show igneous and sedimentary outcrops, respectively. Which do you think is the metamorphic rock? Explain why you ruled out the other rock bodies.

B is the metamorphic rock. A is a sedimentary rock because it is at the highest level and C is an igneous rock because of the minerals visibility.

Granite and basalt are exposed at Earth's surface in a hot, wet region. Will mechanical weathering or chemical weathering predominate? Which rock will weather more rapidly? Why?

Chemical Weathering would Predominate. Basalt would weather more rapidly because its minerals are less stable at surface temperature and pressure.

What mineral property is illustrated in the accompanying photo?

Cleavage, usually micas

What might cause different soils to develop from the same kind of parent material or similar soils to form from different parent materials?

Climate is the most influential factor in soil formation. Temperature and precipitation are the climate elements that exert the strongest impact on soil formation. As noted earlier in this chapter, variations in temperature and precipitation determine whether chemical or mechanical weathering predominates and also greatly influence the rate and depth of weathering. For instance, a hot, wet climate may produce a thick layer of chemically weathered soil in the same amount of time that a cold, dry climate produces a thin mantle of mechanically weathered debris. Time is an important component of every geologic process, including soil formation. The nature of soil is strongly influenced by the length of time processes have been operating. If weathering has been going on for a comparatively short time, the parent material strongly influences the characteristics of the soil. As weathering continues, the influence of parent material on soil is overshadowed by the other soil-forming factors, especially climate. The biosphere plays a vital role in soil formation. The types and abundance of organisms strongly influence the physical and chemical properties of a soil. The lay of the land can vary greatly over short distances. Such variations in topography can lead to the development of a variety of localized soil types. Many of the differences exist because the length and steepness of slopes significantly affect the amount of erosion and the water content of soil. Slope orientation, the direction a slope is facing, also is significant. In the midlatitudes of the Northern Hemisphere, a south-facing slope receives a great deal more sunlight than does a north-facing slope. In fact, a steep north-facing slope may receive no direct sunlight at all. The difference in the amount of solar radiation received causes substantial differences in soil temperature and moisture, which in turn influences the nature of the vegetation and the character of the soil.

This image, taken from the International Space Station, shows a plateau and canyons in central Saudi Arabia. Over a long time span, how will the canyons likely change? How will the plateau be affected? Is there a term that describes the process?

Dentritic pattern will spread?

Is it possible for two igneous rocks to have the same mineral composition but be different rocks? Support your answer with an example.

Gabbro and basalt are two igneous rocks having the same chemical composition, and the same minerals (plagioclase feldspar and pryroxene), but are of different origins. Gabbros forms at depths and cool slowly, whereas basalts are volcanic rocks that crystallize rapidly at the surface of the earth. volcanoes can make volcanic ash and pumice

Give two reasons sedimentary rocks are more likely to contain fossils than igneous rocks.

Gentler pressure and lower temperature allows preservation of past life forms. Sediments are deposited in a variety of different settings at the surface, the rock layers that they eventually form hold many clues to past surface environments and igneous rocks are exposed to heat.

Explain how the processes that create hot-spot volcanic chains differ from the processes that generate volcanic island arcs.

Hot spots volcanoes are caused by rising plumes of mantle material. On the other hand, volcanic island arcs are created by two oceanic slabs converge, and one descends beneath the other in oceanic-oceanic convergence.

Use your understanding of magmatic differentiation to explain how magmas of different composition can be generated in a cooling magma chamber.

If early-formed crystals are more dense (heavier) than the remaining melt, they tend to sink toward the bottom of the magma chamber. Consequently, the lower and upper parts of the magma chamber form rocks of differing composition.

Different processes produce magma in different tectonic settings. Consider magma bodies found at locations A, B, and C in the accompanying diagram and describe the process that most likely triggered the melting that produced each.

In location A, the magma experiences descompression melting. As hot mantle rock ascends, it experiences continuously decreasing pressure. This drop in confining pressure usually initiates decompression melting in the upper mantle. In location B, the introduction of water to generate magma occurs mainly at convergent plate boundaries, where cool slabs of oceanic lithosphere descend into the mantle (Figure 6.35). As an oceanic plate sinks, heat and pressure drive out water from the subducting oceanic crust and overlying sediments. Then in location C, These fluids migrate into the wedge of hot mantle that lies directly above. At a depth of about 100 kilometers (60 miles) this wedge of mantle rock is hot enough that the addition of water leads to some melting. Partial melting of the mantle rock peridotite generates hot basaltic magma whose temperatures may exceed 1250°C (nearly 2300°F).

If you hiked to a mountain peak and found limestone at the top, what would that indicate about the likely geologic history of the rock there?

It is most likely that the mountain was submerged in water at one point

Refer to the accompanying photo to answer the following: The white line shows the approximate location of a fault that displaced these furrows created by a plow. What type of fault caused the offset shown? Is this a right-lateral or left-lateral fault? Explain.

It's a strike-slip fault. It's a left lateral fault because it's moving to the left.

Explain why an eruption of Mount Rainier similar to the 1980 eruption of Mount St. Helens could be considerably more destructive.

Located near big city where people live in valley homes built on deposits left by lahars from past volcanos. Mount Rainer also has a thick snow mantle year round and glacial ice. If an eruption occurred, lahars (destructive mudflow) may produce as well as floods, landslides and a series of earthquakes. Mount Rainer is also larger than Mount St. Helens.

On the accompanying Richter scale diagram, first determine the Richter magnitude ML for an earthquake at 400 kilometers distance, with a maximum amplitude of 0.5 millimeter. Second, for this same earthquake (same ML), determine the amplitude of the biggest waves for a seismograph 40 kilometers from the hypocenter.

ML is 4. 50 amplitude

Some people predict that California will sink into the ocean. Is this idea consistent with the theory of plate tectonics? Explain.

No because California is in the Pacific plate and California's bedrock is continental crust and will not subduct in oceanic crust. California's major fault is the San Andreas, which is a transform fault. Transform faults move in horizontal plane with two plates sliding by each other.

The accompanying photo shows a footprint on the Moon left by an Apollo astronaut in material popularly called lunar soil. Does this material satisfy the definition we use for soil on Earth? Explain why or why not. You may want to refer to Figure 8.11.

No because there is no oxygen, water, organic matter in the Moon. Therefore it does not sastify the definition for soil on Earth.

Describe how plants promote mechanical and chemical weathering but inhibit erosion.

Plants roots in search of minerals and water grow into fractures and help to wedge rocks apart. Also certain plants, fungi and lichens produce acids or other compounds that aid in the chemical weathering of earth materials. Root systems inhibit by binding and helping to hold soils and rocks in place.

Research the minerals quartz and calcite. List five physical characteristics that may be used to distinguish one from another.

Quartz: No cleavage/fracture, hardness=7, any color, glassy appearance, doesn't react to HCI. Calcite: 3 directions of cleavage, hardness=3, white/yellow/colorless, milky/transparent, reacts to HCI

Describe at least one situation in which an internal process might cause or contribute to a mass movement process.

Rockslide. occur when blocks of bedrock break loose and slide down a slope. Usually rockslides take place in a geologic setting where the rock strata are inclined or where joints and fractures exist parallel to the slope. When such a rock unit is undercut at the base of the slope, it loses support, and the rock eventually gives way.

The accompanying photo shows Shiprock, a well-known landmark in the northwestern corner of New Mexico. It is a mass of igneous rock that represents the underground "plumbing" of a now-vanished volcano. Extending toward the upper left is a related wall-like igneous structure known as a dike. The igneous features are surrounded by sedimentary rocks. Explain why these once deeply buried igneous features now stand high above the surrounding terrain. What term from Section 8.2 applies to this situation?

Sheeting. It takes place due to the great reduction in pressure that occurs when the overlying rock is eroded away. As the overburden is removed, the outer parts of the granitic mass expand more than the rock below and separate from the rock body. Continued weathering eventually causes the slabs to separate and peel off, creating exfoliation domes.

The sedimentary rock coquina, shown below, formed in response to interactions among two or more of Earth's spheres. List the spheres associated with the formation of this rock and write a short explanation for each of your choices.

Th coquina has shells of shell fish. Hence, the coquina rock must be associated with the biosphere. The shale is formed of very small particles at the bottom of the water bodies which is hydrosphere. The shale is at times formed in parts of lithosphere. Therefore, the coquina rock is associated with biosphere, hydrosphere, and lithosphere.

Why is the Vishnu Schist visible at Earth's surface?

The Vishnu schist was exposed when sedimentary layers above it were eroded

This black-and-white photo from the 1930s shows Franklin Roosevelt enjoying the hot springs at the presidential retreat at Warm Springs, Georgia. The temperature of these hot springs is always near 32°C (90°F). This area has no history of recent volcanic activity. What is the likely reason these springs are so warm?

The groundwater circulates at great depths, it becomes heated, and it rises to the surface.

Australian marsupials (kangaroos, koalas, etc.) have direct fossil links to marsupial opossums found in the Americas. Yet the modern marsupials in Australia are markedly different from their American relatives. How does the breakup of Pangaea help to explain these differences (Hint: See Figure 4.22.)?

The marsupials were forced to migrate that is why their fossils can be found on different continents.

What process might have been responsible for the formation of the Vishnu Schist? How does this process differ from the processes that formed the sedimentary rocks that are atop the Vishnu Schist?

The metamorphic process. The metamorphic process forced plate tectonics to compress and bury rocks miles deep into the crust, whereas; the sedimentary process produce layers that are a mixture of soft and tough rocks.

During a field trip with your geology class, you visit an exposure of rock layers similar to the one sketched in the accompanying figure. A fellow student suggests that the layer of basalt is a sill. You disagree. Why do you think the other student is incorrect? What is a more likely explanation for the basalt layer?

The student is incorrect because a sill would not have vesicles. The lava flow affected the bottom layer partially into sandstone and then cooled therefore the layer of shale on top is because of weathering

Of the two main sources of energy that drive the rock cycle—Earth's internal heat and solar energy—which is primarily responsible for each of the three groups of rocks found on and within Earth? Explain your reasoning.

The sun provides energy for surface processes such as weathering, erosion, and transport, and the earth's internal heat provides energy for processes like subduction, melting, and metamorphism.

You go for a jog on a beach and choose to run near the water, where the sand is saturated. With each step, you notice that your footprint quickly fills with water, but that water is not coming in from the ocean. What is this water's source? For what earthquake-related hazard is this phenomenon a good analogy?

The water is coming from the saturated pores of the sand. With each step you are compressing the sand grains together and squeezing the pore water out, it flows up to the surface where there is less pressure, and fills the footprint. This is a good analogy for part of the phenomenon called liquefaction.

The cemetery in this photo is located in New Orleans, Louisiana. As in other cemeteries in the area, all of the burial plots are above ground. Based on what you have learned in this chapter, suggest a reason for this rather unusual practice.

The water table is barely below the surface and half of the city is below sea level?

The Ural Mountains exhibit a north-south orientation through Eurasia. How does the theory of plate tectonics explain the existence of this mountain belt in the interior of an expansive landmass?

Two plates with continental crust converge. Accretion of microcontinent.

Assume that the number of protons in a neutral atom is 92 and the atomic mass is 238.02. (Hint: Refer to the periodic table in Figure 2.5 to answer this question.) What is the name of the element?

Uranium and 92 electrons

Describe the concept of elastic rebound. Develop an analogy other than a rubber band to illustrate this concept.

When stress is applied to crustal rocks, they respond by bending, and in doing so they store elastic energy much like a rubber band does when it is stretched. Once the strength of the rock is exceeded, the rock fractures and movement takes place along this fracture or fault. This slippage allows the deformed rocks to snap back to their original shape: a process called elastic rebound. It is the springing back of the rock that produces the vibrations we call an earthquake.

Is it likely that rocks similar to the Vishnu Schist exist elsewhere but are not exposed at Earth's surface? Explain.

Yes, under the surface.

Would you expect all the crystals in an intrusive igneous rock to be the same size? Explain why or why not.

Yes. The rate of cooling strongly influences crystal size. If magma cools very slowly, ions can migrate over great distances. Consequently, slow cooling results in the formation of fewer, larger crystals. On the other hand, if cooling occurs rapidly, the ions lose their motion and quickly combine.

Refer to the accompanying hypothetical plate map to answer the following questions: a. How many portions of plates are shown? b. Explain why active volcanoes are more likely to be found on continents A and B than on continent C. c. Provide one scenario in which volcanic activity might be triggered on continent C.

a. 5 plates b. because continents A and B are moving towards each other, and since the subduction zones are moving into the continental area, they are oceanic-continental convergence, which can trigger volcanoes. c. if continent C is on a hot spot or if one of the plates moves towards C.

Examine the accompanying photo of a mineral that has several smooth, flat surfaces that resulted when the specimen was broken. How many flat surfaces are present on this specimen? How many different directions of cleavage does this specimen have? Do the cleavage directions meet at 90-degree angles?

a. 6 b.3 c. no

Refer to the accompanying diagrams illustrating the three types of convergent plate boundaries and complete the following: a. Identify each type of convergent boundary. b. On what type of crust do volcanic island arcs develop? c. Why are volcanoes largely absent where two continental blocks collide? d. Describe two ways in which oceanic-oceanic convergent boundaries differ from oceanic-continental boundaries. How are they similar?

a. A- Oceanic-Continental boundary, B- Oceanic-Oceanic Boundary, C. Continental-Continental convergence b. Oceanic crust c. The two continental blocks are made of a thick layer of rock which makes it difficult for magma to get through d. the oceanic-oceanic involves two slabs of oceanic lithosphere, while the oceanic-continental, the oceanic lithosphere is subducting beneath continental lithosphere. The similarity they share is that they create volcanoes.

Answer the following questions about divergent plate boundaries, such as the Mid-Atlantic Ridge, and their associated lavas: a. Divergent boundaries are characterized by eruptions of what type of lava: andesitic, basaltic, or rhyolitic? b. What is the main source of the lavas that erupt at divergent plate boundaries? c. What process causes the source rocks to melt?

a. Basaltic b. Iron and magnesium rich magmas c. the crust and the lithosphere are thinned and that causes decompression melting of the underlying mantle

The accompanying image shows a double-decked section of Interstate 880 (the Nimitz Freeway) that collapsed during the 1989 Loma Prieta earthquake and caused 42 deaths. About 1.4 kilometers (nearly a mile) of this freeway section, called the Cypress Viaduct, collapsed, while a similar section survived the vibration. Both sections were subsequently demolished and rebuilt as a single-level structure, at a cost of $1.2 billion. Examine the map and seismograms from an aftershock that show the intensity of shaking observed at three nearby locations to answer the following questions: a. What type of ground material experienced the least amount of shaking during the aftershock? b. What type of ground materials experienced the greatest amount of ground shaking during the same event? c. Which of the two sections of the Cypress Viaduct numbered on the map do you think collapsed: #1 or #2? Explain.

a. Bedrock b. Soft mud c. #2 because it is located in soft mud area, which it's the ground material that experienced the greatest amount of shaking during the same event.

he Middle Fork of the Salmon River flows for about 175 kilometers (110 miles) through a rugged wilderness area in central Idaho. a. Is the river flowing in an alluvial channel or a bedrock channel? Explain. b. What process is dominant here: valley deepening or valley widening? c. Is the area shown in this image more likely near the mouth of the river or the head?

a. Bedrock channel; As the stream moves down the mountain it cuts into the bedrock which creates a bedrock channel. You can see a lot of larger materials like boulders rocks and pebbles. This is the area where you have a lot of weathering and mass wasting. b. valley deepening c. headwaters

Examine the accompanying photo and complete the following: a. What type of volcano is shown? What features helped you classify it as such? b. What is the eruptive style of such volcanoes? Describe the likely composition and viscosity of its magma. c. Which type of plate boundary is the likely setting for this volcano? d. Name a city that is vulnerable to the effects of a volcano of this type.

a. Composite cone; large size b. Interbedded lavas and pyroclastics. Nuee ardente is a fiery pyroclastic flow made of hot gases infused with ash. Flows down sides of a volcano at speeds up to 200 km (125 miles) per hour. composite cones are the product of silica-rich magma having an andesitic composition. However, many composite cones also emit various amounts of fluid basaltic lava and, occasionally, pyroclastic material having a felsic (rhyolitic) composition. c. Found on convergent plate boundaries. Oceanic-continental convergence. d. Fujiyama, a classic composite volcano in Japan; Mount Mayon in Philippines

The accompanying photo, taken near the bottom of the Grand Canyon, shows a quartz vein that has been deformed. a. What type of deformation is exhibited—ductile or brittle? b. Did this deformation most likely occur near Earth's surface or at great depth?

a. Ductile b. At great depth because the structure didn't break apart.

Examine the diagrams depicting the structure of East Africa and the Canadian Rockies. a. Characterize the type of faulting found at each location and identify the differential stresses that produced these landforms. b. Along what type of plate boundary did each of these structures form?

a. East Africa is normal faulting caused by stretching which occurred deep in the Earth, and the stress is tension. On the other hand, the Canadian Rockies are thrust faults that occurred in the shallow part of Earth, and the stress is compression. b. East Africa is a divergent boundary and the Canadian Rockies are convergent boundaries.

a. What observations led Alfred Wegener to develop his continental drift hypothesis? b. Why did most of the scientific community reject the continental drift hypothesis? c. Do you think Wegener followed the basic principles of scientific inquiry? Support your answer.

a. Fit of South America and Africa, fossils match across the seas, ancient climates, and rock types and structure match. b. Main objection to Wegener's proposal was its inability to provide a mechanism. c. Yes because he provided an hypothesis and evidence that supported the continental drift. However, he could not prove how the rocks could move.

Using the geologic definition of mineral as your guide, determine which of the items in this list are minerals and which are not. If something in this list is not a mineral, explain. Gold nugget Seawater Quartz Cubic zirconia Obsidian Ruby

a. Gold Nugget, yes b. Seawater, no because it is a liquid. c. Quartz, yes. d. Cubic zirconia, yes. e. Obisidian, no because it does not have orderly crystalline structure. f. Ruby, yes. g. Glacial ice, yes. h. Amber is not because it has an organic origin and amorphous structure.

Imagine that you are studying seafloor spreading along two different oceanic ridges. Using data from a magnetometer, you produced the two accompanying maps. a. From these maps, what can you determine about the relative rates of seafloor spreading along these two ridges? Explain. b. Using the scale provided, measure the distance in kilometers from the ridge axis to the beginning (right edge) of the yellowish normal polarity stripe for each ridge. By how many kilometers has each side of these ocean basins spread during the past 1 million years?

a. In B we can see the width of normal polarity is less near the ridge axis, which indicate a low spreading rate whereas A has much more width and shows a larger spreading rate. b.

Refer to the accompanying map and the pairs of cities to complete the following: (Boston, Denver), (London, Boston), (Honolulu, Beijing) a. Which pair of cities is moving apart as a result of plate motion? b. Which pair of cities is moving closer as a result of plate motion? c. Which pair of cities is not presently moving relative to each other?

a. London, Boston b. Honolulu, Beijing c. Boston, Denver

Use the accompanying seismogram to answer the following questions: a. Which of the three types of seismic waves reached the seismograph first? b. What is the time interval between the arrival of the first P wave and the arrival of the first S wave? c. Use your answer from Question b and the travel-time graph in Figure 5.14 to determine the distance from the seismic station to the earthquake. d. Which of the three types of seismic waves had the highest amplitude when it reached the seismic station?

a. P wave b. 5 minutes c. 3,700 Kilometers (2300 miles) d. Surface waves

A river system consists of three zones, based on the dominant process operating in each part of the river system. On the accompanying illustration, match each process with one of the three zones: a. Sediment production (erosion) b. Sediment deposition c. Sediment transport

a. Sediment production (erosion)= zone#1 b. Sediment transport= zone#2 c. Sediment deposition= zone#3

Using the accompanying map of the San Andreas Fault, answer the following questions: a. Which of the four segments (1-4) of the San Andreas Fault do you think is experiencing fault creep? b. Paleoseismology studies have found that the section of the San Andreas Fault that failed during the Fort Tejon quake (segment 3) produces a major earthquake every 135 years, on average. Based on this information, how would you rate the chances of a major earthquake occurring along this section in the next 30 years? Explain. c. Do you think San Francisco or Los Angeles has the greater risk of experiencing a major earthquake in the near future? Defend your selection.

a. Segment 2 because it shows no evidence of having produced a major earthquake b. The segment is statistically likely to experience another earthquake of similar magnitude to the 1857 quake after 135 years or in 1992 (which has passed so this could happen soon). c. Los Angeles because it's closer to the Fort Tejon quake

Refer to the accompanying diagrams to answer the following: a. What type of dip-slip fault is shown in Diagram 1? Were the dominant forces during faulting tensional, compressional, or shear? b. What type of dip-slip fault is shown in Diagram 2? Were the dominant forces during faulting tensional, compressional, or shear? c. Match the correct pair of arrows in Diagram 3 to the faults in Diagrams 1 and 2.

a. Strike-slip faulting; shear b. Reverse faulting; compression c. b goes with diagram 2 and a goes with diagram 1

Refer to the accompanying map, which shows the location of the Galapagos Rise and the Rio Grande Rise to answer the following questions: a. Name the type of continental margin found on the west and east coasts of South America. (Hint: See Figure 4.10, page 103) b. Based on your answer to Question a, is the Galapagos Rise or the Rio Grande Rise more likely to end up accreted to South America? Explain your choice. c. In the distant future, how might a geologist determine that this accreted landmass is distinct from the continental crust to which it accreted?

a. The east coast has a convergent plate boundary, while the west coast has a divergent plate boundary. b. The Galapagos Rise because the convergent plate will trigger it to move towards South America. c. compare the materials in the surface and under the surface to determine they are distinct?

Imagine that you are an environmental scientist who has been hired to solve a groundwater contamination problem. Several homeowners have noticed that their well water has a funny smell and taste. Some think the contamination is coming from a landfill, but others think it might be a nearby cattle feedlot or chemical plant. Your first step is to gather data from wells in the area and prepare the map of the water table shown here. a. Based on your map, can any of the three potential sources of contamination be eliminated? If so, explain. b. What other steps would you take to determine the source of the contamination?

a. The landfill because a land subsidence did not occur due to groundwater withdrawal. b. check the wells surrounding the chemical plant and the feedlot.

This image shows the Buddhist monastery Taung Kalat, located in central Myanmar (Burma). The monastery sits high on a sheer-sided rock made mainly of magmas that solidified in the conduit of an ancient volcano. The volcano has since been worn away. Based on this information, what igneous structure do you think is shown in this photo? Would this volcanic structure most likely have been associated with a composite volcano or a cinder cone? Explain how you arrived at your answer.

a. Volcano neck b. because cinder cones die quicker than composite volcanoes, giving composite volcanoes enough time to go through this process

a. Along which type of boundary do most strong earthquakes occur? b. Why might the boundary along the coast of California produce weak earthquakes? c. Notice that divergent boundaries appear to have the fewest earthquakes. One explanation is that these boundaries produce fewer earthquakes. What might be another explanation?

a. convergent plate boundaries b. because the plates are spreading apart c. The rocks locate there are warmer, which prevents them from building up a lot of stored stress.

If you collect a jar of water from a stream, what part of its load will settle to the bottom of the jar? What portion will remain in the water indefinitely? What part of the stream's load would probably not be represented in your sample?

bed load will settle at the bottom. The portion that will remain in the water indefinitely will be the suspended load, and the dissolved load will not be seen.

The accompanying map shows the locations of many of the largest earthquakes in the world since 1900. Refer to the map of Earth's plate boundaries in Figure 4.10, page 103, and determine which type of plate boundary is most often associated with these destructive events.

convergent boundaries; ocean-continental convergence

What is the likely difference between an intermittent stream (one that flows off and on) and a stream that flows all the time, even during extended dry periods?

different water tables

Volcanic islands that form over mantle plumes, such as the Hawaiian chain, are home to some of Earth's largest volcanoes. However, several volcanoes on Mars are gigantic compared to any on Earth. What does this difference tell us about the role of plate motion in shaping the Martian surface?

in order for giant shield volcanoes to form over mantle plumes, the plate overlying the plume must remain stationary for a great deal of time. The volcanoes on Mars indicate that plate motion had little, if anything, to do with shaping the Martian surface.

Refer to Figure 3.1. How does the rock cycle diagram—in particular, the labeled arrows—support the fact that sedimentary rocks are the most abundant rock type on Earth's surface?

there are so many different ways that the sediment is transported and the cemented