Oceanography Chapter 3

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Please identify the word and/or phrase that does NOT fit the pattern. Enter only the letter of the answer (caps, no period, and not the full entry) in the field below. A. rift valley B. oceanic ridge C. oceanic rise D. seaknoll E. seafloor spreading

D

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Please identify the word and/or phrase that does NOT fit the pattern. Enter only the letter of the answer (caps, no period, and not the full entry) in the field below. A. turbidity currents B. graded bedding C. turbidite deposits D. abyssal plains E. deep-sea fans

D

Due to the very harsh environmental conditions, very few types of organisms are found in association with hydrothermal vents.

False

Ocean trenches are deep linear scars in the ocean floor caused by the divergence of plates along divergent plate boundaries.

False

Seamounts form from ancient tablemounts.

False

The continental shelf is generally defined as a steeply sloping zone extending from the shoreline to the shelf break.

False

The three major provinces of the ocean floor are continental margins, deep-ocean basins, and submarine canyons.

False

Turbidity currents are highly erosive and are thought to be responsible for the creation of deep-sea trenches.

False

The method that is used most frequently to investigate sediment and rock layers of the sea floor is:

Sound waves (specifically seismic reflecting profiling).

Sediments of the continental rise can exhibit characteristics similar to those formed by rivers on land.

True

What effect do turbidity currents have on the continental slope?

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

How do turbidity currents affect canyons?

Turbidity currents erode material from canyons as currents move downslope.

Match the term with the appropriate phrase. continental shelf

a generally flat zone extending from the shore to the shelf break

Match the term with the appropriate phrase. multi-beam sonar

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

Sediments deposited by the process of suspension settling produce the main sediment found on ___________. Select only one answer.

abyssal plains

Extending from the base of the continental rises into the deep-ocean basins are flat depositional surfaces called:

abyssal plains.

Match the term with the appropriate phrase. ocean trench

deep linear scars on the deep-ocean floor caused by plate convergence

What are turbidity currents?

dense mixtures of sand, mud, and other debris that move at high speeds down submarine canyons

Oceanic ridges and rises result from seafloor spreading along:

divergent plate boundaries

Consider a continental margin that has a very broad, flat continental shelf and a slope that descends 1 km to the deep ocean basin. Based on this information, this margin is ___________________.

far from an oceanic ridge

Match the term with the appropriate phrase. abyssal plain

flat depositional surfaces that cover extensive portions of the deep-ocean basins

All the following are considered part of the continental margin except the:

fracture zone

What is the characteristic layering of an individual turbidity current deposit called?

graded bedding

What types of deposits do turbidity currents leave in alluvial fans?

graded bedding that begins as coarse material and becomes finer upward

The direction of motion along a seafloor transform fault is:

in the same direction as the plates are spreading.

How often do turbidity currents occur?

infrequently

Transform faults have all of the following characteristics except:

movement occurs in the same direction.

Segments of the oceanic ridge system that are gentler and less rugged in slope due to faster rates of seafloor spreading are called:

oceanic rises.

Along the margins of the Pacific are found most of Earth's:

oceanic trenches.

Most ocean floor features owe their origins to _________.

plate tectonic processes

What would you look for as evidence that a rock layer formed from materials deposited by ancient turbidity currents?

repeated sequences of graded bedding that begin as coarse material and become finer upward

Identify the major feature of a slow-spreading mid-ocean ridge

rift valley

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

Volcanic peaks on the deep-ocean floor with conical tops are called:

seamounts.

Underwater avalanches of muddy water mixed with rocks and debris are:

turbidity currents

precision-depth recorder (PDR)

uses high frequency sound waves to measure ocean depth

Nearly all oceanic islands are __________. (Choose the best answer.)

volcanic in origin

Of the following statements about Earth's hypsographic curve (figure shown below), which is/are true? The hypsographic curve shows that the average depth of the ocean is about four times the average height of the continents. The hypsographic curve shows that a majority of the ocean floor is below 4 kilometers deep. The hypsographic curve shows the percentage of Earth's surface area that is covered by ocean waters. The hypsographic curve shows the amount of water in the oceans. The hypsographic curve shows that a majority of the exposed land is below 1 kilometer in elevation.

1 2 3 5

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

1 2 3 5 and 6

What process(es) affect the shape and structure of continental shelves? erosion of sediment large fluctuations in sea level the creation of pillow lavas along the mid-ocean ridge eposition of sediment major climate changes, such as ice ages

1 2 4 and 5

The greatest proportion of Earth's surface lies in this elevation/depth interval.

4,000-5,000 m below sea level

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Please identify the word and/or phrase that does NOT fit the pattern. Enter only the letter of the answer (caps, no period, and not the full entry) in the field below. A. black smoker B. deep focus earthquake C. hydrothermal vent D. rift valley E. white smoker

B

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Please identify the word and/or phrase that does NOT fit the pattern. Enter only the letter of the answer (caps, no period, and not the full entry) in the field below. A. abyssal hill B. abyssal plain C. submarine canyon D. seamount E. tablemount

C

Passive continental margins are characterized by all the following except:

Deep-sea trenches

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Please identify the word and/or phrase that does NOT fit the pattern. Enter only the letter of the answer (caps, no period, and not the full entry) in the field below. A. continental margin B. active margin C. convergent active margin D. transform active margin E. rift valley

E

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?

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.

Black smokers are hydrothermal vents that discharge superheated water with high concentrations of metal sulfides.

True

Oceanic ridges are cut by a number of transform faults, which offset spreading zones.

True

Satellite measurements of the ocean surface can be used to make maps of the seafloor.

True

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 __________.

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 __________.

settling velocity

The two relatively flat areas on the hypsographic curve represent

some interior continental areas/coastal plains and abyssal plains on the ocean floor.

What is turbidity?

suspended sediment