8: Chapter The Dynamic Planet MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which layer of the planet forms 80 percent of Earth's total volume, and has an average density of 4.5 grams per cm2? A) oceanic crust B) mantle C) continental crust D) core Answer: B 2) Consider a beach environment with large, powerful waves breaking along the shore. Given the nature of this environment, which of the following sediments would be least likely to be deposited there? A) sand B) silt and clay C) gravel and sand Answer: B 3) Tectonic forces A) erode the surface of the earth B) form sedimentary rock C) control soil formation processes D) warp, fold, and uplift rock Answer: D 4) Continental crust is basically _________, whereas oceanic crust is basically __________. A) thin; thick B) granite; basalt C) basalt; granite D) sima; sial Answer: B 5) The history of life on Earth is chronicled in which type of rock? A) igneous B) sedimentary C) metamorphic Answer: B 6) Which of the following is not true of the metamorphism process? A) It can be accomplished by chemical processes. B) It can be accomplished by pressure. C) It involves melting of the original rock. D) It can be accomplished by heat. Answer: C 7) The Sierra Nevada mountain range in California is an example of A) an exposed batholith B) a lava flow C) an extrusive igneous formation D) a volcano
Answer: A 8) Uniformitarianism assumes that A) Earth is quite young and is shaped by dramatic events B) mountains, plains, and canyons formed by catastrophic events C) the same physical processes we see today are a key to understanding the processes that have been operating throughout geologic time D) catastrophic episodes have regularly occurred Answer: C 9) The density of material below the Moho is __________ that above it. A) greater than B) the same as C) less than Answer: A 10) What percent of the Earth's crust is composed of only eight natural elements? A) 75 B) 50 C) 99 D) 25 Answer: C 11) Which of the following can occur when seismic waves encounter a layer in the Earth's interior? A) Their speed can change. B) They can be absorbed. C) They can be reflected or refracted. D) All of the above can occur, depending upon the nature of the layer. E) None of the above - seismic waves cannot penetrate below the crust of the Earth. Answer: D 12) Salt is an example of ________ rock. A) extrusive igneous B) intrusive igneous C) sedimentary D) metamorphic Answer: C 13) A batholith forms from A) sediment accumulation in a depression B) metamorphic rock C) extrusive igneous rock D) intrusive igneous rock Answer: D
14) An assemblage of minerals bound together is called a A) rock B) molecule C) granitic compound D) mineral Answer: A 15) The heat that melted the early Earth was derived from A) radioactive decay B) sunlight C) nuclear fusion D) chemical reactions Answer: A 16) The idea that Earth formed only a few thousand years ago is A) based on little physical evidence and is more appropriately considered a belief B) basically accepted today by science C) referred to as uniformitarianism D) the basis of the geologic time scale Answer: A 17) A rock made of clay particles is most likely to have formed in which of the following environments? A) desert B) beach C) swamp Answer: C 18) Approximately 90 percent of Earth's magnetic field is generated in the A) inner core B) upper mantle C) outer core D) lower mantle Answer: C 19) An element or combination of elements that forms an inorganic, natural compound is called a A) molecule B) tectonic rock C) granitic compound D) mineral Answer: D 20) Which of the following lists the correct sequence of divisions in the geologic time scale, from largest to smallest? A) eon, era, period, epoch B) period, eon, era, epoch C) epoch, era, eon, period D) era, eon, epoch, period Answer: A 21) Which of the following is not a sedimentary rock?
A) bituminous coal B) shale C) sandstone D) marble Answer: D 22) Which of the following are located along the midocean ridges? A) evaporite deposits B) outcrops of granite C) old oceanic sediments D) volcanoes Answer: D 23) Which of the following is exogenic in nature? A) flows of heat and materials in the mantle B) volcanism C) weathering D) earthquakes Answer: C 24) Which of the following is not true regarding Earth's magnetic field? A) The Earth's magnetic field will probably reverse in the next few thousand years. B) A given field orientation can last billions of years. C) It causes magnetic particles in cooling magma to align with magnetic field lines. D) Transition periods, during which reversals occur, last an average of about 4000 to 8000 years. Answer: B 25) Which of the following is not an example of an age-relationship based on absolute dating? A) The oldest known rocks on Earth are 3.96 billion years old. B) The Vishnu schist at the bottom of the Grand Canyon is 2 billion years old. C) The Coconino formation in the Grand Canyon is older than the Kaibab formation. D) The dinosaurs became extinct 65 million years ago. Answer: C 26) The transition zone from the outer core to the mantle is ________ and is known as the ____________ discontinuity. A) uneven; Gutenberg B) smooth; Moho C) smooth; Gutenberg D) uneven; Moho Answer: A 27) Earth's interior is
A) arranged with lighter elements toward the center and heavier elements toward the crust B) not subject to internal differentiation C) heated unevenly by the heat of radioactive decay D) evenly mixed throughout Answer: C 28) Earth's magnetic field A) remains a mystery as to its cause B) is principally generated in the inner core C) is variable, and it has phased to zero some nine times during the past 4 million years D) is constant in its intensity Answer: C 29) Knowledge of Earth's interior is derived from A) direct sampling of the interior using deep-test wells B) historic and prehistoric records C) indirect evidence involving the analysis of seismic waves D) work in Earth's deepest caverns and caves Answer: C 30) Which of the following is incorrectly matched? A) exogenic - external processes B) radioactive decay heat - exogenic energy source C) weathering - exogenic breaking and dissolving the crust D) endogenic - internal processes Answer: B 31) The thickness of Earth's crust ranges from A) the surface down to 2900 km (1800 mi) B) 70 km to 250 km (43 mi to 155 mi) C) the surface to an unknown depth D) 5 km to 60 km (3 mi to 37 mi) Answer: D 32) The majority of the Earth's crust is composed of ________ rock. A) sedimentary B) carbonate C) metamorphic D) igneous Answer: D
33) Glaciers that once covered the Hudson Bay area melted 8,000 years ago. As a result of this, the bay is gradually rising. In another 10,000 years or so, it will have risen above sea level and become dry. This process can best be considered an example of A) catastrophism B) orogenesis C) accretion D) isostasy Answer: D 34) Which of the following supports the continental drift concept? A) magnetic field patterns preserved in the rocks B) radioactive decay dating of rocks on either side of a spreading center C) plant and animal fossil records D) all of these support the theory E) none of these is valid evidence of continental drift Answer: D 35) The Hawaiian Islands were formed as a result of A) a continental-oceanic plate collision B) activity along a midocean ridge C) an oceanic-oceanic plate collision D) a rising plume of magma from the mantle Answer: D 36) Which of the following is incorrect relative to hot spots across Earth's surface? A) They are responsible for the formation of the Hawaiian-Emperor Islands chain. B) Hot spots can occur beneath both oceanic and continental crust. C) They remain relatively fixed in relationship to the migrating plates. D) Hot spot activity is unrelated to the formation of Iceland, which sits atop a sea-floor spreading ridge in the North Atlantic. Answer: D 37) The size of sediment transported from an area and subsequently deposited is a function of A) the relief of the area B) the energy of the environment C) the energy of the transporting agent D) all of these E) none of these Answer: D 38) The major rocks of Earth's crust are classified into principal types based on A) relative and absolute locations B) three specific rock-forming processes, i.e., the manner in which they formed
C) mineral composition D) element composition Answer: B 39) Limestone is an example of which type of rock-forming process? A) metamorphic B) sedimentary C) igneous Answer: B 40) Which of the following is not part of the hydrologic cycle? A) radioactive decay B) erosion C) transportation D) sedimentation Answer: A 41) The ancient roots of mountains are usually composed of _________ rocks. A) igneous B) metamorphic C) sedimentary Answer: B 42) Which of the following is an example of an intrusive, igneous rock? A) pluton B) lava flow C) dome D) volcano Answer: A 43) The sea-floor spreading center that led to the formation of the Atlantic Ocean accelerated dramatically between A) 135 and 65 million years ago B) 465 and 225 million years ago C) 4.6 and 2 billion years ago D) the end of the Pleistocene and today Answer: A 44) The presence of 180-million-year-old salt domes in the Gulf Coast region of the U.S. indicates that A) a sea used to cover the area but subsequently evaporated B) subsidence is now occurring due to the withdrawal of magma from the region C) the area was subjected to plate collisions, which caused metamorphism to occur D) the area was once volcanically active E) none of these are indicated Answer: A 45) The aesthenosphere can best be described as A) plasma-like B) a liquid C) plastic-like D) a rigid solid Answer: C
46) Which of the following lists is in the correct sequence from youngest to oldest? A) Tertiary, Quaternary, Cretaceous B) Holocene, Precambrian, Cenozoic C) Holocene, Pleistocene, Pliocene, Miocene D) Paleozoic, Cenozoic, Mesozoic Answer: C 47) The shape of the Earth's surface results from A) the radioactive decay of atoms B) gravity C) the action of wind, water and ice D) all of the above E) Gravity and wind, water, and ice only. Answer: D 48) The ocean floor subducts under because continents A) the weight of the continents is so great that they push the ocean floor material downward B) the ocean floor is made of felsic minerals and is heavier than continental material C) the ocean floor has a lower density and therefore sinks more easily D) the ocean floor is made of mafic material and is therefore more dense than continental material E) both a and b Answer: D 49) With increasing depth, the mantle becomes __________ due to greater _________. A) more plastic; pressures B) stiffer; pressures C) more plastic; temperatures D) stiffer; temperatures Answer: B 50) Which of the following is true of divergent plate boundaries? A) rifting occurs there B) new ocean crust can be created there C) tensional forces exist there D) all of these E) none of these Answer: D 51) Which of the following is the fuel for continental drift and plate tectonics?
A) radioactive decay B) solar energy C) nuclear fusion D) chemical reactions in Earth's core Answer: A 52) The principles of buoyancy and balance, when applied to Earth's crust, helps us to explain fluctuations in Earth's outer crust, a property known as A) isostasy B) Moho effect C) orogenesis D) magnetism Answer: A 53) A laccolith is actually a large version of a __________. A) dike B) sill C) discontinuity D) batholith Answer: B 54) Mafic minerals are ______________ minerals. A) dark colored, low density B) light colored, high density C) light colored, low density D) dark colored, high density Answer: D 55) At which of the following locations is new ocean crust being formed? A) rift zones B) along collision zones between two oceanic plates C) in trenches D) along collision zones between two continents Answer: A 56) Marble is a familiar example of which type of rock? A) sedimentary B) extrusive igneous C) metamorphic D) intrusive igneous Answer: C 57) Pangaea is currently dated at A) 65 million years ago B) about half the timespan of Earth's existence C) the beginning of the Holocene D) 4.6 billion years ago E) 225 to 200 million years ago Answer: E 58) Which of the following is matched correctly?
A) magma - lava B) basalt - sedimentary C) granite - metamorphic D) sandstone - igneous Answer: A 59) The boundary between the crust and the rest of the lithospheric upper mantle is a discontinuity known as the A) lithospheric layer B) Moho C) mantle D) Gutenberg Answer: B 60) The three most abundant elements in Earth's crust are A) magnesium, potassium, and oxygen B) oxygen, silicon, and aluminum C) iron, aluminum, and granite D) rock, water, and tectonics Answer: B 61) Which of the following is endogenic in nature? A) volcanism B) stream deposition C) weathering D) glacial erosion Answer: A 62) Tilted layers of quartzite exposed in a mountain range indicate that A) the mountain was covered with water B) sand was deposited on a steeply sloping surface, lithified, uplifted and then exposed at the surface C) limestone was deposited, lithified, metamorphosed, uplifted and exposed D) sand was deposited, lithified, metamorphosed, uplifted and exposed Answer: D 63) Which of the following gives the correct sequence of layers in the Earth, from the surface to the center? A) crust, lower mantle, aesthenosphere, core B) crust, core, lower mantle, aesthenosphere C) aesthenosphere, lower mantle, crust, core D) crust, aesthenosphere, lower mantle, core Answer: D 64) Three types of rock-forming processes compose the A) mineral cycle B) rock cycle C) tectonic cycle D) hydrologic cycle Answer: B
65) The mineral crystals in a sill would be ________ those in a lava flow. A) larger than B) the same size as C) smaller than Answer: A 66) Which of the following gives the correct sequence of layers in the mantle, from bottom to top? A) lower mantle; upper mantle, aesthenosphere B) upper mantle, aesthenosphere, mantle C) aesthenosphere, mantle, upper mantle D) mantle, aesthenosphere, upper mantle Answer: A 67) Which of the following is true of the aesthenosphere? A) It contains pockets of increased heat. B) It carries the crustal plates. C) It flows. D) All of these are true. E) None of these are true. Answer: D 68) Which of the following statements about Earth's core is not true? A) Temperatures and pressures are higher in the inner core than in the outer core. B) Temperatures in the core reach several thousand degrees. C) It is composed primarily of iron. D) The inner core is believed to be liquid and the outer core solid. Answer: D 69) The magma that fuels and produces the volcanic activity around the Pacific Ring of Fire is derived from the A) rise of magma from hot spots, such as those that formed the Hawaiian Islands B) rise of magma along transform faults C) magma extruded from rift zones that are developing along the Pacific Rim D) rise of material that was melted in subduction zones along the Pacific margins Answer: D 70) An unmetamorphosed dike could be composed of which of the following? A) gneiss B) sandstone C) obsidian D) granite Answer: D
71) The ocean floor is a maximum of about 200 million years in age because A) the ocean floor is pushed up onto continental material during plate collisions B) the ocean floor subducts during plate collisions C) hot spots continuously destroy the ocean floor D) the Earth is only 200 million years old E) none of the above - the ocean floor is 3.96 billion years old Answer: B 72) Coal is a fossil fuel formed from A) plants B) dead marine organisms C) blue-green algae D) metamorphosed mafic minerals Answer: A 73) Heat energy and new materials are brought to the surface from the interior by the A) mineral cycle B) rock cycle C) tectonic cycle D) hydrologic cycle Answer: C 74) When geologists or archaeologists dig downward into a unit of rock or sediment, they are digging "back in time." This fact is based on the principle of _________. A) superposition B) uniformitarianism C) catastrophism Answer: A 75) If you were driving down the highway and saw mountains composed of layered strata, you could be confident that you were looking at A) a shield volcano B) batholiths or laccoliths C) sedimentary rocks D) extrusive igneous rock Answer: C 76) Convergent plate boundaries are characteristic of A) lateral motions of plates B) sea-floor spreading centers C) all plate boundaries D) collision zones between plates Answer: D 77) Several large, linear lakes are forming in East Africa. This is evidence of what process? A) compression B) subduction C) isostatic uplift D) rifting Answer: D
78) A rock transformed from any other rock through profound physical and/or chemical processes is referred to as A) igneous B) metamorphic C) sedimentary D) ancient Answer: B 79) At which of the following locations does subduction occur? A) at sea floor spreading zones B) along collision zones between continental and oceanic plates C) along collision zones between two continents D) above mantle hot spots Answer: B TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 80) The Earth's interior has been mapped using seismic waves. Answer: TRUE 81) Scientists recently succeeded in drilling through the crust to reach the mantle. Answer: FALSE 82) The geologic cycle is powered both by exogenic and endogenic energy systems. Answer: TRUE 83) Earthquake and volcanic occurrences do not correlate well with crustal plate boundaries. Answer: FALSE 84) The deepest places in the ocean are those in which rifting occurs. Answer: FALSE 85) The principle of isostasy refers to the horizontal movement of Earth's plates in response to loading and unloading of weight, such as ice or sediment. Answer: FALSE 86) Earth's magnetic field is generated from within the entire planet, rather than in a specific region of Earth's interior. Answer: FALSE
87) An example of an intrusive igneous formation is a pluton. Answer: TRUE 88) A guiding principle of earth science is the principle of uniformitarianism, as opposed to catastrophism. Answer: TRUE 89) Silt and clay are likely to be deposited in a beach environment. Answer: FALSE 90) The uppermost mantle is plastic-like, whereas the aesthenosphere is rigid. Answer: FALSE 91) Alfred Wegner's theory of continental drift was immediately accepted by the scientific community when it was proposed. Answer: FALSE 92) Any rock, either igneous or sedimentary, may be transformed into a metamorphic rock, by going through profound physical and/or chemical changes under increased pressure and temperature. Answer: TRUE 93) The ocean floor is created along midocean ridges. Answer: TRUE 94) The crust is thickest under mountains and thinnest under the oceans. Answer: TRUE 95) Lithification refers to the cementation, compaction, and hardening of sediments. Answer: TRUE SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 96) Rocks that solidify and crystallize from a molten state are called __________. They form from _______________, which is molten rock beneath the surface. Magma is fluid, highly gaseous, and under tremendous pressure. It is either ______________ into
preexisting crustal rocks, known as country rock, or ______________ onto the surface as __________________. Answer: igneous; magma; intruded; extruded; lava ANSWERS MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) B 14) A 2) B 15) A 3) D 16) A 4) B 17) C 5) B 18) C 6) C 19) D 7) A 20) A 8) C 21) D 9) A 22) D 10) C 23) C 11) D 24) B 12) C 25) C 13) D 26) A
42) A 27) C 43) A 28) C 44) A 29) C 45) C 30) B 46) C 31) D 47) D 32) D 48) D 33) D 49) B 34) D 50) D 35) D 51) A 36) D 52) A 37) D 53) B 38) B 54) D 39) B 55) A 40) A 56) C 41) B
57) E 73) C 58) A 74) A 59) B 75) C 60) B 76) D 61) A 77) D 62) D 78) B 63) D 79) B 64) B 65) A 66) A 81) FALSE 67) D 82) TRUE 68) D 83) FALSE 69) D 84) FALSE 70) D 85) FALSE 71) B 86) FALSE 72) A TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 80) TRUE
87) TRUE 93) TRUE 88) TRUE 94) TRUE 89) FALSE 95) TRUE 90) FALSE 91) FALSE 92) TRUE SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 96) igneous; magma; intruded; extruded; lava