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Chapter 14 Convergent Boundaries: Origin of Mountains
Earth: An Introduction to Physical Geology, 9e (Tarbuck/Lutgens)
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14.1
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Multiple-Choice Questions
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1)
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The concept that rocks of the crust and upper mantle are floating in gravitational balance is known as ________.
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A)
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isotropy
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B)
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isostasy
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C)
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isobration
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D)
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isomonism
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Answer:
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B
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Diff: 1
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2)
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According to the crustal, gravitational balance idea, which of the following statements is true?
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A)
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A mountain range undergoing erosion should uplift slowly.
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B)
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As a continental ice sheet thickens, the land beneath should uplift slowly.
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C)
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A basin being filled with sediments should uplift slowly.
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D)
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The crust is thicker under a low lying plain than under a high standing plateau or mountain range.
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Answer:
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A
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Diff: 1
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3)
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The Valley and Ridge Province of the Appalachian Mountains is characterized by ________.
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A)
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sedimentary strata folded in late Paleozoic time
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B)
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deeply eroded, late Paleozoic, fault-block mountains and valleys
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C)
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stratovolcanoes above a volcanic arc
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D)
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crustal stretching as Africa and Eurasia migrated away from North America
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Answer:
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A
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Diff: 1
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4)
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Which of the following best describes the geology of the Pacific coastal regions of western North America including Alaska?
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A)
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An earlier, continental margin broke apart and the geologically similar fragments were tectonically reassembled.
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B)
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Geologically different, microcontinent-sized fragments and terranes, formed elsewhere, were tectonically accreted to North America.
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C)
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A massive subcontinent of old igneous and metamorphic rocks (similar to India) was accreted during late Proterozoic time.
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D)
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Tightly folded, continental shelf strata were squeezed between North America and the convergent, Bering-Siberian subcontinent.
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Answer:
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B
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Diff: 2
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5)
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A(n) ________ is a thick accumulation of sediments and small, tectonic blocks formed of material scraped off a descending, lithospheric plate.
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A)
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mass movement complex
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B)
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continental shelf, terrain complex
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C)
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accretionary-wedge complex
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D)
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subterranean-accumulation complex
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Answer:
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C
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Diff: 1
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6)
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How were the Ural Mountains (Russia) formed?
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A)
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Large, fault blocks of Archean igneous and metamorphic rocks rose as the former Asian and European plates joined to form Eurasia.
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B)
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Marine strata in a basin between the former Asian and European plates were squeezed, folded, and uplifted as the two joined to form the Eurasian plate.
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C)
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Active, normal faulting is elevating large, mountain blocks above the level of the vast plains on both sides of the range.
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D)
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An active volcanic arc, similar to the present-day Aleutian Islands, rose along the southern edge of the Eurasian plate.
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Answer:
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B
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Diff: 1
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7)
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The ranges of the central and southern Rocky Mountains ________.
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A)
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generally contain thick sections of highly folded, Paleozoic, marine strata
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B)
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developed in response to a continent-continent collision
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C)
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are uplifted, blocks that typically have cores of Proterozoic igneous and metamorphic rocks
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D)
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the Paleozoic and Mesozoic sedimentary rocks were elevated and compressed into tight folds; but the deeper, harder rocks of the continental crust were pulled apart by tensional stresses
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Answer:
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C
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Diff: 1
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8)
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During late Paleozoic time, the tectonic configuration of the Appalachian region in eastern North America was most similar to the ________.
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A)
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Andean (west) edge of the South American plate
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B)
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areas of Africa and Arabia bordering on the Red Sea
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C)
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Pacific coastal region from southern California to Alaska
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D)
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Tibetan Plateau and the Himalayan Range
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Answer:
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B
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Diff: 1
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9)
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Which of the following best characterizes the tectonic development of fault-block mountains?
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A)
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normal faults; crustal stretching and brittle failure of the upper crust
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B)
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reverse faults; crustal stretching and brittle failure of the lower crust
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C)
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normal faults; crustal shortening and plastic flowage of the upper crust
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D)
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reverse faults; crustal shortening and plastic flowage of the lower crust
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Answer:
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A
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Diff: 1
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10)
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The Sierra Nevada, CA, and Teton, WY ranges are examples of ________.
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A)
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fault blocks uplifted by late Tertiary to Quaternary normal faulting
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B)
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folding, compression, and thickening of Paleozoic strata in Jurassic time
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C)
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isostatic uplift of crust overthickened in early Paleozoic time
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D)
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uplifted blocks bounded by Quaternary reverse faults
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Answer:
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A
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Diff: 1
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11)
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A good example of a present-day, passive, trailing, continental margin is the ________.
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A)
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north flank of the East Pacific Rise
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B)
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west coast of South America
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C)
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east coast of the Japanese Islands
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D)
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west coast of Africa
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Answer:
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D
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Diff: 1
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12)
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An exotic terrane created by a seamount accreted to a continental margin would be composed ________.
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A)
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of folded, quartz sandstone and shallow water, marine limestone
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B)
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exclusively of granite batholiths and rhyolite welded tuffs
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C)
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mainly of organic-rich, black shales and beach-type sandstones
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D)
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mainly of basaltic lava flows and minor, coralline limestone
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Answer:
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D
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Diff: 2
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13)
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The ________ are a geologically old mountain range folded and deformed during the Paleozoic.
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A)
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Cascades in the northwestern United States
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B)
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Rockies in the western United States
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C)
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Appalachians in the eastern United States
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D)
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Alps in Europe
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Answer:
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C
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Diff: 1
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14)
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The ________ have crust about twice as thick as normal.
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A)
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Coast Ranges and Sierra Nevada in California
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B)
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Blue Ridge Mountains in the southeastern United States
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C)
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Himalayan Range and Tibetan Plateau in northern India and southwestern China
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D)
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Basin and Range Province in Arizona and Nevada
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Answer:
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C
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Diff: 1
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15)
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The ________ of the Appalachian orogen consists of North American, continental shelf strata deposited prior to the late Paleozoic collision with Africa.
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A)
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metamorphic and igneous rocks of the Blue Ridge
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B)
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igneous and regionally metamorphosed rocks of the Piedmont
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C)
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Cretaceous and Tertiary strata of the coastal plain and continental shelf
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D)
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folded, sedimentary rocks of the Valley and Ridge Province
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Answer:
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D
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Diff: 1
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16)
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The Chulitna terrane, Alaska, is a ________ that consists of interbedded, basaltic, lava flows and deep-water, marine limestones.
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A)
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piece of the Cenozoic, Alaskan, continental margin volcanic arc
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B)
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piece of the ancient Pacific Ocean floor
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C)
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tectonically deformed and strongly metamorphosed accretionary wedge
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D)
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piece of a batholith and its time-equivalent, stratovolcano complex
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Answer:
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B
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Diff: 1
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17)
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The ________ is (are) characterized by terrane accretion that has been active throughout most of Mesozoic and Cenozoic time.
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A)
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western margin of Africa
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B)
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southern margins of India and Australia
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C)
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western margin of North America
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D)
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western margin of the Mid-Atlantic Ridge
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Answer:
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C
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Diff: 1
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18)
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Topographically high-standing, mountainous areas generally ________.
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A)
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are underlain by greater than average thicknesses of lower density, crustal rocks
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B)
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subside rapidly to compensate for erosion
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C)
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have thicker, higher density, mantle rocks beneath them at shallow depths
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D)
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experience rapid erosion that thins the crust and causes the area to subside
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Answer:
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A
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Diff: 1
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19)
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Which one of the following is an example of an isostatic movement?
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A)
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stream downcutting following a drop in sea level
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B)
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arching of strata at the center of a dome
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C)
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numerous aftershocks associated with deep-focus earthquakes
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D)
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uplift of areas recently covered by thick, continental ice sheets
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Answer:
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D
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Diff: 1
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20)
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Folded limestones that occur high in the Himalayas were originally deposited as sediments in a ________.
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A)
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marine basin between India and Eurasia
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B)
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Cenozoic fault basin between Africa and Arabia
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C)
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deep ocean trench along the southern margin of India
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D)
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late Paleozoic syncline north of the Tibetan Plateau
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Answer:
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A
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Diff: 1
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21)
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Since the early Mesozoic, the ________ has been passive tectonically.
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A)
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western margin of North America
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B)
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western margin of South America
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C)
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southern margin of Eurasia
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D)
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eastern margin in the United States
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Answer:
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D
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Diff: 1
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22)
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Accretionary wedges are formed ________.
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A)
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at the edge of the overriding plate facing a subduction zone
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B)
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at the base of a passive continental margin
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C)
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on the oceanic plate side of a transform fault
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D)
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around oceanic plate volcanoes fed by long-lived hot spots in the mantle
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Answer:
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A
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Diff: 1
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23)
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The severed, upper part of a Jurassic seamount might occur as a distinctive, small terrane ________.
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A)
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on a passive-margin continental shelf
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B)
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in an arc of stratovolcanoes far inland from a convergent margin
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C)
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along the boundary between two Precambrian shield areas
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D)
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in an accretionary wedge shoved onto an active, continental margin
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Answer:
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D
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Diff: 2
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24)
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The term ________ refers specifically to geologic mountain building.
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A)
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orogneisses
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B)
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orogeny
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C)
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orthogeny
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D)
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orthogonal
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Answer:
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B
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Diff: 1
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25)
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Subduction zones include all of the following except for ________.
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A)
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deep ocean trenches
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B)
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forearc basins
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C)
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suture zones
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D)
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volcanic arcs
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Answer:
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C
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Diff: 1
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26)
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Backarc regions are characterized by ________.
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A)
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compression
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B)
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shearing
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C)
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uplift
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D)
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extension
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Answer:
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D
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Diff: 1
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27)
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Volcanism along a continental arc is dominated by the eruption of ________.
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A)
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basaltic lava flows
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B)
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andesitic lavas and pyroclastic materials
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C)
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rhyolitic pyroclastic materials and lavas
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D)
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all of the above
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Answer:
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B
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Diff: 1
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28)
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________ basins are characterized by thick sequences of relatively undeformed sedimentary rocks.
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A)
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Forearc
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B)
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Backarc
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C)
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Transform fault
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D)
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Evaporite
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Answer:
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A
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Diff: 2
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29)
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A(n) ________ is a zone where two continents collide, often preserving slivers of oceanic lithosphere between the colliding plates.
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A)
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passive margin
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B)
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ophiolite
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C)
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suture
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D)
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terrane
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Answer:
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C
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Diff: 1
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14.2
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Word Analysis Questions
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Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.
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1)
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A) Himalayas B) Andes C) Appalachians D) Alps
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Answer:
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Andes
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Diff: 1
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2)
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A) seamount B) deep-ocean trench C) volcanic arc D) forearc
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Answer:
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seamount
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Diff: 1
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3)
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A) compression B) fold-and-thrust-belt C) suture D) island arc
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Answer:
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island arc
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Diff: 2
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4)
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A) Japan B) Andes C) Appalachians D) Sierra Nevada
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Answer:
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Appalachians
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Diff: 1
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14.3
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True/False Questions
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1)
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Folds and thrust faults in the rocks of the Appalachian region formed in late Paleozoic time when Africa collided with North America.
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Answer:
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TRUE
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Diff: 1
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2)
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The Himalayan Mountains and Tibetan Plateau are still rising today as Eurasia slides beneath the Indian subcontinent.
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Answer:
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FALSE
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Diff: 1
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3)
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As the Pleistocene ice sheets in Canada grew and thickened, the crust beneath the ice gradually subsided.
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Answer:
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TRUE
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Diff: 1
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4)
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Uplift generally accompanies erosion of mountain ranges composed of overthickened, low density, crustal rocks.
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Answer:
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TRUE
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Diff: 1
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5)
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Terrane accretion generally occurs along a divergent boundary between a continental plate and an oceanic plate.
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Answer:
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FALSE
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Diff: 1
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6)
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Adjacent terranes accreted to a continent will generally show similar geologic histories for the time before joining and different geologic histories thereafter.
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Answer:
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FALSE
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Diff: 1
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7)
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Accretionary wedges develop along subduction zones where sediments and other rocks are scraped off a descending plate and piled against the leading edge of the overriding plate.
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Answer:
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TRUE
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Diff: 1
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8)
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Volcanic island arcs and granitic, batholithic zones develop along convergent margins on the overriding plate above an oceanic plate sinking into the mantle.