Earth Science, 13e (Tarbuck) Chapter 13 The Ocean Floor 1) Which one of the following is NOT part of the continental margin? A) continental shelf B) continental slope C) continental rise D) continental trench Answer: D Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 2) It is thought that submarine canyons on the continental slope have been generated by A) streams when sea level was much lower than it is today B) streams when sea level was much higher than it is today C) a submarine glaciations D) turbidity currents Answer: D Diff: Topic: 13.3 Continental Margins Bloom's: Applying 3) Which one of the following would most likely be covered with thick turbidite layers? A) axial rift zone of an active mid-ocean spreading center B) upper part of a steep, narrow, submarine canyon C) deep-sea fan at the base of a continental slope D) ocean floor around a conical-shaped seamount Answer: C Diff: Topic: 13.3 Continental Margins Bloom's: Applying 4) Which of the following is NOT true of deep ocean trenches? A) They are long and narrow depressions B) They are sites where plates plunge back into the mantle C) They are geologically very stable D) They may act as sediment traps Answer: D Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Understanding Copyright © 2012 Pearson Education, Inc 5) The BEST definition of the outer edge of the continental shelf is that point where A) the gradient becomes very gentle B) the water depth reaches 100 fathoms C) it meets an oceanic ridge D) a rapid steepening of the gradient occurs Answer: D Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 6) Seamounts A) are a special type of oceanic trench B) are volcanoes that form on the ocean floor C) form only in the Pacific Ocean basin D) are submarine canyons found near Australia Answer: B Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering 7) Submarine canyons found on the continental slope are believed to have been created A) by rivers during the ice age B) by faulting C) because of a plate plunging into the mantle D) none of these Answer: D Diff: Topic: 13.3 Continental Margins Bloom's: Remembering 8) Which of the following is associated with ocean ridges? A) rift zones B) mountainous topography C) volcanic structures D) all of these Answer: D Diff: Topic: 13.5 The Oceanic Ridge Bloom's: Understanding Copyright © 2012 Pearson Education, Inc 9) How calcareous oozes form? A) The particles are precipitated in warm surface waters and sink to the bottom B) The particles are precipitated by bottom-dwelling organisms C) The particles are precipitated in the water column below the depth of sunlight penetration and then sink to the bottom D) The particles settle out from calcite-rich turbidity currents at depths greater than 15,000 feet Answer: A Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 10) Sediments derived primarily from the products of weathering on the continents are called A) terrigenous sediment B) biogenous sediment C) hydrogenous sediment D) both terrigenous and biogenous sediment Answer: A Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 11) Manganese nodules are an example of A) terrigenous sediment B) biogenous sediment C) hydrogenous sediment D) both terrigenous and biogenous sediment Answer: C Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 12) Minerals that crystallize directly from seawater are examples of A) terrigenous sediment B) biogenous sediment C) hydrogenous sediment D) both terrigenous and biogenous sediment Answer: C Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Understanding Copyright © 2012 Pearson Education, Inc 13) The gently sloping submerged surface extending from the shoreline toward the deep ocean is termed the A) continental shelf B) continental slope C) continental rise D) submarine canyon Answer: B Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 14) The crests of mid-oceanic ridges A) are heavily mantled with sediment B) lie at depths exceeding kilometers C) contain active rift zones D) are geologically old features Answer: C Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Understanding 15) develop where oceanic lithosphere bends downward and sinks into the mantle A) Submarine canyons B) Abyssal seamounts C) Deep ocean trenches D) Rift valleys on mid-ocean ridges Answer: C Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 16) An echo sounder operates by measuring the time required for a A) light beam to travel from a satellite at a known altitude to the sea bottom and back B) radar beam to travel from a harbor patrol boat to a fuzz-buster on a speeding yacht C) radar beam to travel from a ship to the seafloor and back D) sound pulse travels from a ship to the seafloor and back Answer: D Diff: Topic: 13.2 An Emerging Picture of the Ocean Floor Bloom's: Understanding Copyright © 2012 Pearson Education, Inc 17) The oceans cover approximately percent of Earth's surface A) 40 B) 50 C) 60 D) 70 Answer: D Diff: Topic: 13.1 The Vast Ocean World Bloom's: Remembering 18) The Ocean is largest A) Atlantic B) Pacific C) Indian D) Arctic Answer: B Diff: Topic: 13.1 The Vast Ocean World Bloom's: Remembering 19) Which ocean has the greatest average depth? A) Atlantic B) Pacific C) Indian D) Arctic Answer: B Diff: Topic: 13.1 The Vast Ocean World Bloom's: Remembering 20) Concerning the distribution of land and water, which of the following statements is true? A) The percentage of land and water is about the same in both the Northern and Southern Hemispheres B) The Southern Hemisphere has much more water surface than the Northern Hemisphere C) The Northern Hemisphere has much more water surface than the Southern Hemisphere D) None of the above is true Answer: B Diff: Topic: 13.1 The Vast Ocean World Bloom's: Remembering Copyright © 2012 Pearson Education, Inc 21) The continental rise is located A) at the top of a mid-ocean ridge B) at the top of the continental slope C) between an abyssal plain and continental slope D) at the seaward edge of a deep ocean trench Answer: C Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 22) Which one of the following concerning mid-ocean ridges is false? A) They are sites for submarine eruptions of basaltic lava B) They are where young lithosphere is added to the edges of spreading, oceanic plates C) Terrigenous sediment coverings are very thin or absent D) Sediments include thick siliceous ooze deposits and sandy turbidite beds Answer: D Diff: Topic: 13.5 The Oceanic Ridge Bloom's: Understanding 23) The Ocean has more extensive abyssal plains than the Pacific Ocean because it has fewer trenches to trap sediments moving down the continental slope A) Indian B) Atlantic C) Arctic D) none of these Answer: B Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering 24) "Black smokers" are associated with A) oceanic ridges B) mineral-rich waters C) hot water D) all of these Answer: D Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Applying Copyright © 2012 Pearson Education, Inc Give the term of ocean floor sediment for each phrase biogenous terrigenous hydrogenous 25) manganese nodule Answer: hydrogenous Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 26) calcareous ooze Answer: biogenous Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 27) abyssal plain clay Answer: terrigenous Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering Word Analysis 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 28) echo sounder doppler radar sidescan sonar Answer: Doppler radar Diff: Topic: 13.2 An Emerging Picture of the Ocean Floor Bloom's: Understanding 29) continental shelf continental rise Answer: continental volcanic arc Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 30) rift valley subduction Answer: rift valley Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Understanding continental slope radar altimeters continental volcanic arc volcanic island arc Copyright © 2012 Pearson Education, Inc trench 31) manganese nodules calcareous ooze Answer: evaporites Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Understanding metal sulfides evaporites 32) The west coast of South America and the east coast of North America have very different continental margins Answer: TRUE Diff: Topic: 13.3 Continental Margins Bloom's: Remembering 33) Abyssal plains with sediments covering the seafloor igneous rocks are more extensive in the central Pacific basin than in the North Atlantic Answer: FALSE Diff: Topic: Figure 13.13 Bloom's: Remembering 34) Submerged, flat-topped seamounts are known as guyots Answer: TRUE Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering 35) The Atlantic and Pacific basins have oceanic ridges; the Indian Ocean has no oceanic ridge Answer: FALSE Diff: Topic: Figure 13.15 Bloom's: Remembering 36) Manganese nodules not accumulate below 4500 meters depth because the manganese minerals are highly soluble in seawater below that depth Answer: FALSE Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 37) Turbidites and siliceous oozes are both biogenous sediments Answer: FALSE Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering Copyright © 2012 Pearson Education, Inc 38) Submarine canyons form the deepest parts of the ocean basins Answer: FALSE Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 39) Compared to the Southern Hemisphere, a higher percentage of the Northern Hemisphere is water covered Answer: FALSE Diff: Topic: Figure 13.1 Bloom's: Remembering 40) The continental rise lies at the bottom of the continental slope Answer: TRUE Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 41) Seafloor hot springs occur mainly in oceanic, abyssal plains Answer: FALSE Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Understanding 42) Sand, silt, and clays deposited on the ocean floor are described as terrigenous sediments Answer: TRUE Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 43) The most extensive mountain range on Earth extends for about 65,000 kilometers on the ocean floor and is known as the Answer: mid-ocean ridge Diff: Topic: 13.5 The Oceanic Ridge Bloom's: Remembering 44) Flat-topped volcanic structures located on the floor of the deep ocean basin are termed Answer: guyots Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering Copyright © 2012 Pearson Education, Inc 45) A prominent feature of the Mid-Atlantic Ridge is a very deep linear valley known as a(n) valley Answer: rift Diff: Topic: 13.5 The Oceanic Ridge Bloom's: Remembering 46) The gently sloping submerged surface extending from the shoreline toward the deep ocean is termed the Answer: continental shelf Diff: Topic: 13.3 Continental Margins Bloom's: Remembering 47) sediment consists of shells and hard parts of marine organisms Answer: Biogenous Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 48) Valleys that lead from the continental shelf into deeper waters are known as Answer: submarine canyons Diff: Topic: 13.3 Continental Margins Bloom's: Remembering 49) continental margins typically exhibit wide, extensive, continental shelves Answer: Passive Diff: Topic: 13.3 Continental Margins Bloom's: Understanding 50) Manganese nodules are an example of sediment Answer: hydrogenous Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 51) A(n) is a volcanic mountain, built up from the seafloor that never reached the sea surface Answer: seamount Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering 10 Copyright © 2012 Pearson Education, Inc 52) continental margins occur where oceanic lithosphere is being subducted beneath the edge of a continent Answer: Active Diff: Topic: 13.3 Continental Margins Bloom's: Remembering 53) A(n) is the vast, relatively deep, flat, sediment-covered portion of the deep-ocean basin Answer: abyssal plain Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering 54) A(n) marks the site where old, oceanic lithosphere begins its descent into a subduction zone Answer: trench Diff: Topic: 13.4 The Deep Ocean Basin Bloom's: Remembering Critical Thinking and Discussion Use complete sentences, correct spelling, and the information presented in Chapter 13 to answer the questions below 55) Discuss the distribution of seafloor sediments in the ocean basins What are the different types of sediments, and what are the factors that control their distribution (geologic setting, climate, etc.)? Answer: The sediments nearest the continents are a record of terrestrial occurrences on Earth The sediments on the abyssal plain are a record of happenings in the photic zone of the ocean The sediments are wedge-shaped, being thinnest at the divergent boundary (mid-ocean ridge) and thickest next to the continents Diff: Topic: 13.6 Types of Seafloor Sediment Bloom's: Applying 11 Copyright © 2012 Pearson Education, Inc 56) What type of continental margin is illustrated in the diagram below? Answer: active continental margin Diff: Topic: Figure 13.11 Bloom's: Understanding 12 Copyright © 2012 Pearson Education, Inc 57) Examine Figure 13.B from Earth Science, 13e below Briefly explain the main points of Charles Darwin's hypothesis on coral atoll formation Have we tested his hypothesis and is it still thought to be correct today? Can you think of another possible explanation that would explain the origin of such coral atolls? Answer: Corals colonize and ring a volcanic island once it’s been formed Then, erosion attacks the top of the volcano and the plat also sinks when its away from the hotspot The corals have to grow upwards as a result, because they need light Eventually their growth doesn't keep pace with the sinking and the reef is submerged, becoming a seamount Diff: Topic: Box 13.1 Bloom's: Analyzing 13 Copyright © 2012 Pearson Education, Inc  ... Education, Inc 57) Examine Figure 13.B from Earth Science, 13e below Briefly explain the main points of Charles Darwin's hypothesis on coral atoll formation Have we tested his hypothesis and is it still... Answer: B Diff: Topic: 13.1 The Vast Ocean World Bloom's: Remembering 19) Which ocean has the greatest average depth? A) Atlantic B) Pacific C) Indian D) Arctic Answer: B Diff: Topic: 13.1 The Vast... Topic: 13.6 Types of Seafloor Sediment Bloom's: Remembering 43) The most extensive mountain range on Earth extends for about 65,000 kilometers on the ocean floor and is known as the Answer: mid-ocean