OCE ch.3

What percent of volcanic activity takes place on the sea floor? 85 75 60

85

How many volcanic peaks are known to exist on the Pacific sea floor? -10,000 to 15,000 -15,000 to 20,000 -> 20,000

> 20,000

The mid-ocean ridge is entirely volcanic and is composed of ________ lavas characteristic of the oceanic crust. granitic basaltic andesitic rhyolitic

basaltic

The measurement of ocean depth and the charting of sea-floor topography is called __________. hydrology bathymetry tomography

bathymetry

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

sound waves (specifically seismic reflecting profiling).

The distance of 1 fathom was standardized to equal exactly ________ feet. 5 7 3 6

6

Active continental margins are characterized by which of the following? Sparse earthquake activity Shallow coastal waters Deep-sea trenches

Deep-sea trenches

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 1500 m/second, what is the water depth in meters? -5550 meters -3000 meters -11,100 meters -7400 meters

5550 meters

Which of the following is the deepest part of the ocean? Abyssal plain Shelf Slope Rise

Abyssal plain

The speed of sound in seawater varies with ________. salinity temperature pressure All of the answers

All of the answers

What kind of hydrothermal vent has the highest temperature and mineral content? -White smoker -Geothermal heat pump -Warm-water vents -Hot springs -Black smoker

Black smoker

Characteristics of passive continental margins include which of the following? -Broad continental shelves -Chains of islands -Thin sediment accumulation

Broad continental shelves

Passive margins are usually produced over geologic time by which of the following? -Subduction of oceanic crust and submarine volcanic activity -Hot spot volcanism forming a chain of islands and seamounts -Continental rifting and continued sea floor spreading

Continental rifting and continued sea floor spreading

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

Continental slope

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

Fracture zone

The first systematic bathymetric measurement of the oceans were made in 1872 about the ________. -Comet -HMS Challenger -Odyssey

HMS Challenger

Which gas is being emitted from hydrothermal vents? Oxygen Hydrogen sulfide Hydrogen sulfate

Hydrogen sulfide

Which one of the following is not considered a true type of oceanic island? -Islands that are parts of continents (such as British Isles) -Islands associated with volcanic activity along the mid-ocean ridge (such as Ascension Island along the Mid-Atlantic Ridge) -Islands associated with hotspots (such as Hawaiian islands) -Islands that are island arcs and associated with convergent plant boundaries (such as Japanese archipelago).

Islands that are parts of continents (such as British Isles)

Which of the following is the deepest trench? Middle America Kuril Mariana

Mariana

A continental margin, like the one shown in the image, contains which of the following? -Submarine canyons -Submarine fans -Off-shore faults

Off-shore faults

The majority of ocean trenches are along the margins of which ocean? Atlantic Southern Pacific Indian

Pacific

Deep-ocean trenches and volcanic arcs result from the collision of two plates at convergent plate boundaries and mostly occur along the margins of which of the following oceans? -Pacific Ocean -Southern Ocean -Atlantic Ocean -Arctic Ocean

Pacific Ocean

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

Pacific Ocean

Identify the major feature of a slow-spreading mid-ocean ridge. Trench Rift valley Volcanic arc

Rift valley

Which of the following techniques used to determine ocean bathymetry is illustrated in the image? -Seismic Reflection -Side-scan Sonar

Seismic Reflection

Which of the following continental margin features is illustrated in the image? -Rift valleys -Deep-ocean trenches -Submarine fans -Off-shore faults -Submarine canyons

Submarine canyons

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

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.

abyssal hills or seaknolls.

Directly seaward of the continental shelf is a more steeply sloping region called the: -abyssal plain. -trench. -continental rise. -mid-ocean ridge. -continental slope.

continental slope.

A tablemount is another name for a(n) ________. -abyssal hill -island -nematath -guyot

guyot

The direction of motion along a seafloor transform fault is: in the same direction as the ridge offset. in the same direction as the plates are spreading. associated with turbidity currents.

in the same direction as the plates are spreading.

Graded bedding provides evidence that __________. -submarine canyons were cut by streams during ice ages when the continental shelves were above sea level -turbidity currents carry large particles farther than smaller, lighter particles -large, heavy particles settle out first as current velocity decreases

large, heavy particles settle out first as current velocity decreases

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

oceanic ridges.

Segments of the oceanic ridge system that are gentler and less rugged in slope due to faster rates of seafloor spreading are called: -deep-sea trenches. -convergent plate boundaries. -transform faults. -fracture zones. -oceanic rises.

oceanic rises.

Abyssal plains are large, flat features that cover about ________ of the planet. -one-quarter -one-third -one-half -one-fifth

one-third

Most large ocean floor features owe their origins to _________. plate tectonic processes ocean currents biological activity erosion and weathering

plate tectonic processes

The instrument that emits a high-frequency sound beam to measure the depth of the ocean developed in the 1950s is the ________. precision-depth recorder (PDR) Seabeam SeaMARC

precision-depth recorder (PDR)

Measurement of ocean floor bathymetry from satellites relies on ___________. Select only one answer. -sea surface elevation, which varies depending on the shape of the underlying sea floor -calculations of how much water versus rock there is at any ocean location -water temperature, which is higher in areas of shallow ocean waters and can easily be detected by satellites

sea surface elevation, which varies depending on the shape of the underlying sea floor

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 __________. - 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

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

Relatively few abyssal plains are located in the Pacific Ocean due to: -the presence of convergent active margins. -its smaller size compared to other ocean basins. -the absence of convergent active margins. -the presence of seamounts.

the presence of convergent active margins.

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

volcanic

Nearly all oceanic islands are __________. (Choose the best answer.) -volcanic in origin -formed at high-standing areas of mid-ocean ridges -formed at hotspots as lithospheric plates pass over mantle plumes -parts of continents separated from continents -parts of volcanic island arcs

volcanic in origin

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

white smokers