Deck 4: Ocean Basins

Question 1

Active continental margins are located ____.

A)along the east coast of the United States
B)along the east coast of South America
C)on the west coasts of both North and South America
D)all around Africa

Answer 1

C

Question 2

Intense offshore drilling for oil and gas takes place primarily on the ____.

A)abyssal plain
B)continental shelf
C)continental rise
D)Mid-Atlantic Ridge

Answer 2

B

Question 3

One of the widest and thickest continental rises is found ____.

A)in the Red Sea
B)in the Pacific at the active margin called the "Ring of Fire"
C)in the Bay of Bengal
D)off the east coast of Florida

Answer 3

C

Question 4

Which statement accurately describes a turbidity current?

A)A fast dense current of water that carries sediments offshore
B)The cause of mid-ocean trenches
C)A phenomenon associated with violent atmospheric storms at sea
D)An event that always occurs at river mouths in shallow water, but does not extend into water more than 50 meters (165 feet)deep

Question 5

Submarine canyons ____.

A)always run parallel to coast
B)have gradual slopes and are very wide
C)can never cut into rock
D)cut into the continental shelf and may extend almost to the shore

Question 6

The Andes mountain range is an example of a(n)____.

A)ridge system
B)island arc system
C)passive margin
D)active margin convergent zone

Question 7

Where is the widest continental shelf located?

A)The Arctic Sea north of Siberia
B)The western edge of South America
C)The margin surrounding the Hawaiian Islands
D)The Emperor Seamounts

Question 8

Water depth over continental shelves averages only about ____.

A)16 meters(50 feet)
B)35 meters(115 feet)
C)75 meters (250 feet)
D)100 meters (300 feet)

Question 9

The islands bordering deep-sea trenches are ____.

A)also referred to as "black smokers"
B)accumulations of sediments on the margins of the trenches
C)formed from the activities of coral and other organisms
D)eruptive volcanoes called island arcs

Question 10

The average elevation of the continents is ____.

A)8,848 meters (16,000 feet)
B)840 meters (2,760 feet)
C)3,800 meters (12,000 feet)
D)5,000 meters (15,000 feet)

Question 11

The origin of submarine canyons is not well understood, but is most likely to be ____.

A)erosional, caused by a combination of stream erosion and turbidity currents
B)tectonic, representing down-folds of rock within the continental shelf
C)organic, resulting from the activities of burrowing organisms
D)glacial, through the process of depositing rock debris on the shelf

Question 12

Which statement most accurately describes how the continental rise is formed?

A)From the convergence of oceanic plates at passive continental margins
B)From volcanic activity at active continental margins
C)From the accumulation of sediments at the base of the continental slope
D)From sedimentation surrounding spreading centers

Question 13

Which statement accurately describes active continental margins?

A)They are regions of great geological stability.
B)They are characteristic of the margins of the Atlantic Basin.
C)They are areas of frequent earthquakes and volcanoes, where lithospheric plates are converging.
D)They are areas where lithospheric plates are actively moving apart.

Question 14

The transition between the shelf and the deep seafloor is the ____.

A)littoral zone
B)continental slope and rise
C)abyssal plain
D)mid-ocean ridge

Question 15

The continental shelf is a ____.

A)narrow strip on the East Coast of the United States
B)steep zone dropping off to the deep seafloor like a cliff
C)featureless plain unlike the neighboring continental slope
D)gently sloping platform with a variable landscape

Question 16

How can a satellite sense the contours of the ocean bottom from space?

A)By shining a laser through the ocean to see the bottom
B)By using radar to sense the height of the sea surface over submerged features
C)By using sonar to measure ocean bottom contours directly
D)By sensing changes in gravity as it flies over trenches and mountain ranges

Question 17

The submerged outer edge of a continent is called the ____.

A)abyssal plain
B)continental margin
C)ocean basin
D)continental convergence zone

Question 18

The apron of accumulated sediment at the base of the continental slope is known as the ____.

A)continental rise
B)abyssal hills
C)abyssal plains
D)mid-ocean mountains

Question 19

Submarine canyons occur ____.

A)at the part of an ocean basin nearest the poles
B)at the part of an ocean basin nearest the equator
C)on the continental shelf and continental slope
D)at the center of an ocean basin, at the edges of the mid-ocean ridge

Question 20

The discovery and study of ocean floor contours is called ____.

A)bathymetry
B)abyssomethry
C)stratigraphy
D)paleoceanography

Question 21

The Emperor Sea Mounts are found in the ____.

A)Sagasso Sea
B)South Pacific
C)North West Pacific
D)coastal region of Australia

Question 22

Hydrothermal vents are located near ____.

A)passive continental margins
B)zones of rapid seafloor spreading
C)the edges of the deep sea trenches
D)the margins of the Hawaiian chain

Question 23

The deepest part of the ocean is the ____.

A)Peru-Chile Trench
B)Mid-Atlantic Ridge
C)Mariana Trench
D)Abyssal plains

Question 24

Guyots are often formed near spreading centers.

Question 25

The deep-ocean basin includes which of the following features?

A)continental shelf
B)coral reefs
C)abyssal plains
D)the shelf break

Question 26

Hydrothermal vents such as black smokers are found at spreading centers.

Question 27

The shelf break is the transition between the continental slope and the abyssal plains.

Question 28

Ocean trenches ____.

A)have submerged erosional features
B)are arc-shaped depressions in the oceanic crust that occur at subduction zones
C)consist of glacial troughs dating back to the Ice Age
D)are erosional canyons cut by turbidity currents

Question 29

Passive continental margins line coasts that are far from tectonically active areas.

Question 30

Abyssal hills are small extinct volcanoes commonly associated with ____.

A)seafloor spreading
B)convergent zones
C)active continental margins
D)continental shelves

Question 31

Scientists think that turbidity currents contribute to the formation of submarine canyons.

Question 32

The deepest features in the ocean are ____.

A)continental slopes
B)abyssal plains
C)submarine canyons
D)ocean trenches

Question 33

A seamount is a volcanic projection that does not rise above the surface.

Question 34

Trenches and island arcs are found at spreading centers.

Question 35

Abyssal plains and abyssal hills cover a quarter of Earth's surface.

Question 36

Continental shelves can be made of either granite crust, basalt crust, or both.

Question 37

The landscape of the seafloor away from the continental margins could best be described as ____.

A)a single featureless plain
B)a smooth descent with the deepest portions farthest from land
C)similar in rock type, sediment thickness, and erosional processes to those found on the land
D)oceanic ridge systems and huge abyssal plains with hills, volcanoes, and trenches

Question 38

The Challenger expedition used multibeam echo sounders to contour the seafloor.

Question 39

Flat-topped seamounts that rise from the ocean floor are called ____.

A)ridges
B)island arcs
C)guyots
D)abyssal hills

Question 40

The mid-ocean mountains, such as the ridges and rises, are ____.

A)similar in origin to the Alps, the Rockies, and the Appalachians
B)composed of folded and faulted marine sedimentary rocks
C)constructed of volcanic basalt
D)similar in size and features to most continental mountains

Question 41

What methods do scientists use to determine the bathymetry of the ocean floor, and how do they work?

Question 42

Distinguish between active and passive continental margins.

Question 43

Abyssal plains and abyssal hills cover about 25% of the surface of Earth. What are the characteristics of each of these features?

Question 44

What is a submarine canyon and how are they formed?

Question 45

What is the deepest feature in the ocean? Where is this feature located, and how did it form? Is this feature, and others like it, tectonically stable or tectonically active?