OCE1001 CH3

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern. Rift valley Active margin Transform active margin Convergent active margin Continental margin

Rift valley

The first recorded attempt to measure the ocean's depth was conducted using which of the following techniques? Side-scan Sonar Sounding Magnetometer Multibeam Sonar Seismic Reflection

Sounding

Which of the following is the predominant process that forms the thick blanket of sediment on abyssal plains the deep-ocean floor? Precipitation Undersea streams Melting icebergs Black smokers Suspension settling

Suspension settling

Judge the following sentence according to the criteria given below: Multibeam SONAR systems have resolution limitations in deep water BECAUSE beams of sound spread out with depth. The assertion and the reason are both correct, and the reason is valid. The assertion and the reason are both correct, but the reason is invalid. The assertion is correct, but the reason is incorrect. The assertion is incorrect, but the reason is correct. Both the assertion and the reason are incorrect.

The assertion and the reason are both correct, and the reason is valid.

Characteristics of passive continental margins include which of the following? Volcanic and earthquake activity Deep-sea trenches Chains of islands Thin sediment accumulation Broad continental shelves

Broad continental shelves

Active continental margins are characterized by which of the following? Shallow coastal waters Broad continental shelves No sediment accumulation Sparse earthquake activity Deep-sea trenches

Deep-sea trenches

What features are associated with a passive continental margin? Choose all that apply. Hints Flat coastal terrain narrow continental shelf trench ridge continental rise

Flat coastal terrain continental rise

What is a linear sea floor feature that is seismically inactive, occurs beyond offset mid-ocean ridge segments, and the relative movement between two points on either side of the feature is in the same direction? Nemataths Seaknolls Guyots Transform fault Fracture zone

Fracture zone

Which of the following features is related to transform faults along mid-ocean ridges? Continental rise Fracture zone Submarine canyon Continental slope Continental shelf

Fracture zone

The distinctive type of sedimentary layering that has largest particles on the bottom and smallest particles on the top, with intermediate sized particles in the middle, is called which of the following? Turbidity Currents Suspension Deposits Graded Bedding Nonconformities Sandstone Layering

Graded Bedding

To which planet is NASA sending the spacecraft InSight to study crustal movements similar to earthquakes? Hints Saturn Venus Neptune Mars Europa

Mars

Why is the average depth of the ocean much greater than the average height of land? Hints Oceanic crust is cooler than continental crust. Continental crust is less buoyant than oceanic crust. Continental crust is thinner than oceanic crust. More erosion happens on land than in the ocean. Oceanic crust is more dense than continental crust.

Oceanic crust is more dense than continental crust.

Tamu Massif, the largest single volcano on Earth occurs in which of the following oceans? Atlantic Ocean Southern Ocean Pacific Ocean Indian Ocean Arctic Ocean

Pacific Ocean

Judge the following sentence according to the criteria given below: Few abyssal plains are located in the Pacific Ocean BECAUSE turbidity currents only occur along passive continental margins. The assertion is incorrect, but the reason is correct. The assertion and the reason are both correct, and the reason is valid. The assertion is correct, but the reason is incorrect. The assertion and the reason are both correct, but the reason is invalid. Both the assertion and the reason are incorrect.

The assertion is correct, but the reason is incorrect.

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern. Pillow basalts Metal sulfide deposits Trenches Rift valley Seamounts

Trenches

The average slope of the continental shelf is approximately ________. a tenth of a degree one to two degrees one-half to one degree greater than five degrees two to five degrees

a tenth of a degree

Volcanic features on the ocean floor that are less than 1,000 meters (0.6 miles) tall are called: abyssal hills or seaknolls. seamounts. tablemounts. oceanic ridges. oceanic trenches.

abyssal hills or seaknolls.

Extending from the base of the continental rises into the deep-ocean basins are flat depositional surfaces called: continental shelves. continental slopes. abyssal hills. abyssal plains. tablemounts.

abyssal plains.

The majority of ocean trenches are associated with ___________. Choose all that apply. Hints volcanic arcs and active continental margins subduction zones and associated faults the Pacific Ring of Fire very deep ocean water depths the mid-ocean ridge narrow or no continental shelves

all but mid-ocean ridge

Satellites use microwave beams to measure sea level to an accuracy of four ________. meters centimeters millimeters kilometers decimeters

centimeters

Hypsographic curve

cumulative plot of the frequency of depth or elevation

Older lithosphere is destroyed in association with: mid-ocean ridges. spreading centers. fracture zones. hydrothermal vents. deep-sea trenches.

deep-sea trenches.

What is the characteristic layering of an individual turbidity current deposit called? Hints layered stratum velocity profile grand layering graded bedding rip current

graded bedding

Volcanic peaks that are below sea level but rise more than 1 kilometer above the deep-ocean floor and have a flattened top are called ________. guyots nemataths seaknolls seamounts islands

guyots

Most large ocean floor features owe their origins to _________. Hints extreme pressure at depth plate tectonic processes biological activity erosion and weathering ocean current activity

plate tectonic processes

Volcanic peaks on the deep-ocean floor with conical tops are called: tablemounts. oceanic trenches. seamounts. oceanic ridges. submarine canyons.

seamounts.

The method that is used most frequently to investigate sediment and rock layers of the sea floor is: drilling. light waves. sound waves (specifically seismic reflecting profiling). satellite observation. direct observation.

sound waves (specifically seismic reflecting profiling).

What is turbidity? Hints suspended sediment air bubbles brown algae microscopic floating marine life water currents

suspended sediment

Along the margins of the Pacific are found most of Earth's: abyssal hills or seaknolls. seamounts. oceanic ridges. oceanic trenches. tablemounts.

oceanic trenches.

With respect to mid-ocean ridges, transform faults are: associated with hydrothermal vents. parallel to the rift valley. located in submarine canyons. perpendicular to the ridge axis.

perpendicular to the ridge axis.

Warm water (From 30°C to 350°C) hydrothermal vents form: abyssal hills. cold seeps. turbidity currents. black smokers. white smokers.

white smokers.

The greatest proportion of Earth's surface lies in this elevation/depth interval. Hints 4,000 - 5,000 m below sea level 0 - 1,000 m above sea level 5,000 - 6,000 m below sea level 1,000 - 2,000 m above sea level 3,000 - 4,000 m below sea level

4,000 - 5,000 m below sea level

A ship's fathometer (an echo sounder) transmits a sound pulse and records the return of an echo 7.4 seconds later. If the speed of sound in water is 1,500 m/second, what is the water depth in meters? Hints 5,550 meters 3,000 meters 11,100 meters 4,550 meters 7,400 meters

5,550 meters

What percent of Earth's volcanic activity, each year, takes place on the seafloor? 95% 90% 65% 85% 75%

85%

Passive margins are usually produced over geologic time by which of the following? The closing of an ancient sea to form a salt rich lake Hot spot volcanism forming a chain of islands and seamounts Subduction of oceanic crust and submarine volcanic activity Continental rifting and continued sea floor spreading Transform faulting along a continental margin or a mid-ocean ridge

Continental rifting and continued sea floor spreading

Where does the deep-ocean basin begin along a passive continental margin? Abyssal plain Shoreline Continental rise Continental shelf Continental slope

Continental slope

Which of the following is a difference between passive and active continental margins? Hints Convergent active margins have continental borderlands associated with basins and islands along the coast, whereas passive margins have a flat continental shelf. Convergent active margins have a more extensive continental rise. Passive margins have narrower continental shelves. Convergent active margins will have a steep continental slope, whereas passive margins will have a more gradual slope. Transform active margins will have a trench, whereas passive margins will not.

Convergent active margins will have a steep continental slope, whereas passive margins will have a more gradual slope.

Can you explain why atolls extend from the surface of the ocean down to great depths into the sea? Corals, which make up these ring-shaped structures, can only live where water is warmed and illuminated by sunlight, no more than approximately 45 meters deep. How do you explain an atoll that extends thousands of meters deep? Hints Pieces of coral from other reefs are carried farther out into the ocean, where they act like seeds and start new coral reefs. These corals quickly grow up into the warmer parts of the ocean where they thrive and form round atolls as a means of trapping warmer water around them. The coral reef once formed around an active volcano. The reef became a barrier reef, with hard skeletons of previous colonies acting as the scaffolding for new ones on top. The volcano gradually sank into sea, moving with the plate it rested on, as the coral continued to grow upward, leaving the atoll as a ring structure at the top. Corals deep in the ocean can survive because they are warmed by seamounts instead of the sun. The atoll consists of layers of coral reef alive at the surface and near seamount vents. Sea currents circulate nutrients to the reef deeper than 45 meters and provide a rigid force to keep the coral reef at the surface.

Corals deep in the ocean can survive because they are warmed by seamounts instead of the sun. The atoll consists of layers of coral reef alive at the surface and near seamount vents.

Judge the following sentence according to the criteria given below: The Pacific Ring of Fire is home to the majority of Earth's active volcanoes and large earthquakes BECAUSE of the prevalence of divergent plate boundaries along the Pacific Rim. The assertion and the reason are both correct, and the reason is valid. The assertion and the reason are both correct, but the reason is invalid. The assertion is correct, but the reason is incorrect. The assertion is incorrect, but the reason is correct. Both the assertion and the reason are incorrect.

The assertion is correct, but the reason is incorrect.

Which part of Earth's cumulative hypsographic curve includes the mid-ocean ridges? The gentle slope above sea level The long and flat part below sea level The shallowest slope below sea level The steep deepest part below sea level The steep segment above sea level

The shallowest slope below sea level

What effect do turbidity currents have on the continental slope? Hints Turbidity currents heat up the surrounding seawater above the continental slope. Turbidity currents are erosive to the continental slope and, as a result, carve out submarine canyons. Turbidity currents are rather small, so they essentially have no effect on the continental slope. Turbidity currents transport liquid oil reserves to the continental slope. Turbidity currents make the continental slope less steep.

Turbidity currents are erosive to the continental slope and, as a result, carve out submarine canyons.

Which of the following best describes turbidity currents? Muddy water brought to the ocean by rivers and streams to form a delta Rift-valley sediments found within the depression at mid-ocean ridges Metal-rich deposits that form on the flanks of submarine volcanoes Turbid water that kills coral and other photosynthesizing creatures by blocking light Underwater avalanches of muddy water mixed with rocks and other debris

Underwater avalanches of muddy water mixed with rocks and other debris

What common item is used in this video to demonstrate a turbidity current? Silly Putty a can of soda a large jar filled with water and sediment a balloon a candle

a large jar filled with water and sediment

Multi-beam sonar

a method of mapping the topography of the ocean floor along a strip up to 60 km wide

The direction of motion along a seafloor transform fault is: influenced by underwater boundary currents. associated with turbidity currents. in the same direction as the ridge offset. perpendicular to the direction of plate movement. in the same direction as the plates are spreading.

in the same direction as the plates are spreading.

The island of Java is an example of a volcanic island associated with volcanic activity at a ________. transform fault rift valley mid-ocean ridge island arc hotspot

island arc

Bathymetry

measurement of ocean depth and seafloor topography

New lithosphere is produced in association with: deep-sea trenches. hydrothermal vents. transform faults. fracture zones. oceanic ridges.

oceanic ridges.

In comparison with other ocean basins, major sedimentary features such as continental rises and abyssal plains are relatively rare in the Pacific. The primary reason for their scarcity in the Pacific is that __________. Hints turbidity currents are rare in the Pacific, so little sediment is carried down the continental slopes the Pacific Ocean is too large for those features to form sediment is trapped within the trenches of the convergent plate boundaries ringing the Pacific rivers do not carry much sediment into the Pacific the numerous volcanoes of the Pacific rim and islands prevent normal sedimentation

sediment is trapped within the trenches of the convergent plate boundaries ringing the Pacific

The reason the deposit on the bottom forms the way it does is a result of __________. Hints shaking speed settling velocity density stratification slosh speed wave size

settling velocity

The correct order of seafloor features from the coast to the mid-ocean ridge is: rise, abyssal plain, slope, shelf. abyssal plain, rise, slope, shelf. abyssal plain, shelf, slope, rise. slope, rise, shelf, abyssal plain. shelf, slope, rise, abyssal plain.

shelf, slope, rise, abyssal plain.

Satellites are used to map the ocean floor because ________. the shape of the ocean surface reflects large features on the seafloor they can't cover areas where ships have not produced surveys they are affected by surface weather they can only "see" small areas of the seafloor at one time they are inexpensive to build and launch

the shape of the ocean surface reflects large features on the seafloor

Seismic reflection profile

used to determine ocean structure beneath the sea floor

Precision-depth recorder (PDR)

uses high frequency sound waves to measure ocean depth

All true oceanic islands are ________ in origin. volcanic erosional metamorphic sedimentary collisional

volcanic

Seamounts and abyssal hills are ________ in origin. sedimentary metamorphic seismic volcanic erosional

volcanic

Which of the following is an example of an active continental margin? Choose all that apply. Hints west coast of the United States west coast of Africa east coast of the United States east coast of Brazil west coast of Chile

west coast of the United States west coast of Chile