Ch. 3

Oceanic ridges and rises result from seafloor spreading along ________.

divergent plate boundaries

Warm water (From 30°C to 350°C) hydrothermal vents form:

white smokers.

New lithosphere is produced in association with:

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:

oceanic rises.

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

oceanic trenches.

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

abyssal plains.

RQQ) The measurement of ocean depth and the charting of seafloor topography is called __________.

bathymetry

Older lithosphere is destroyed in association with:

deep-sea trenches.

Directly seaward of the continental shelf is a more steeply sloping region called the:

continental slope.

RQQ) Trenches are typically associated with ________.

convergent continental margins

With respect to mid-ocean ridges, transform faults are:

perpendicular to the ridge axis.

RQQ) Most large ocean floor features owe their origins to _________.

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).

UC) 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 features on the ocean floor that are less than 1000 meters tall are called ________.

seaknolls

Volcanic peaks that are below sea level but rise more than 1 kilometer above the deep-ocean floor and have a pointy top like an upside-down ice cream cone are called ________.

seamounts

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

seamounts.

RQQ) 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

Relatively few abyssal plains are located in the Pacific Ocean due to:

the presence of convergent active margins.

Satellites are used to map the ocean floor because ________.

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

RQQ) Where a mid-ocean ridge is offset, the linear feature connecting and between the crests of the ridge segments is called a __________.

transform fault

What percent of Earth's volcanic activity, each year, takes place on the seafloor?

85%

Passive margins are usually produced over geologic time by which of the following?

Continental rifting and continued sea floor spreading

Where are the deepest portions of the world's oceans found?

At convergent plate boundaries

Where does the deep-ocean basin begin along a passive continental margin?

Continental slope

Characteristics of passive continental margins include which of the following?

Broad continental shelves

Active continental margins are characterized by which of the following?

Deep-sea trenches

Which of the following is the standard unit of ocean depth?

Fathom

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?

Fracture zone

Which of the following features is related to transform faults along mid-ocean ridges?

Fracture zone

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.

Passive margin

Is a linear sea floor feature that has the following properties a transform fault, a fracture zone, or neither? It is seismically active, it occurs between offset mid-ocean ridge segments, and the relative movement between two points on either side of the feature is in the same direction.

Neither

Is a linear sea floor feature that has the following properties a transform fault, a fracture zone, or neither? It is seismically inactive, it occurs between offset mid-ocean ridge segments, and the relative movement between two points on either side of the feature is in the same direction.

Neither

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

Tamu Massif, the largest single volcano on Earth occurs in which of the following oceans?

Pacific Ocean

Which of the following is the predominant process that forms the metallic minerals in and around black smokers?

Precipitation

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.

Submarine canyon

Which of the following is the predominant process that forms the thick blanket of sediment on abyssal plains the deep-ocean floor?

Suspension settling

Judge the following sentence according to the criteria given below: Few abyssal plains are located in the Pacific Ocean BECAUSE the deep-ocean trenches found on the convergent active margins of the Pacific Ocean prevent sediment from moving past the continental slope.

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

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 is correct, but the reason is incorrect.

UC) Of the following statements about Earth's hypsographic curve, which is/are true? Choose all that apply.

The hypsographic curve shows that a majority of the ocean floor is more than 4 kilometers deep. The hypsographic curve shows that a majority of the exposed land is below 1 kilometer in elevation. 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 the percentage of Earth's surface area that is covered by ocean waters.

Which part of Earth's cumulative hypsographic curve includes the continental shelves of passive margins?

The shallowest slope below sea level

Which part of Earth's cumulative hypsographic curve includes linear scars in the ocean floor, caused by the collision of two plates along convergent plate margins?

The steep deepest part below sea level

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

abyssal plains

UC) Of the following items, which is/are associated with a passive continental margin? Choose all that apply.

a continental rise a wide continental shelf

RQQ) An oceanographic vessel is mapping a section of the ocean floor stretching for tens of miles in all directions. The seafloor is extremely flat, with a slope of less than one degree, and the water depth is about 4,500 meters. The area being mapped is most likely a(n) __________.

abyssal plain

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

The Big Island of Hawaii is an example of a volcanic island associated with volcanic activity at a ________.

hotspot

RQQ) Graded bedding provides evidence that __________.

large, heavy particles settle out first as current velocity decreases

UC) Of the following techniques, which one(s) can be used to map the sea floor? Choose all that apply.

sending sound through water (sonar) using satellites to measure the sea surface recording many depths using a long cable direct visitation of the sea floor

The correct order of seafloor features from the coast to the mid-ocean ridge is:

shelf, slope, rise, abyssal plain.

The two relatively flat areas on the hypsographic curve represent:

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

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

sound waves (specifically seismic reflecting profiling).

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

turbidity currents.

All true oceanic islands are ________ in origin.

volcanic

Seamounts and abyssal hills are ________ in origin.

volcanic

Worldwide, scientists estimate that there are about 125,000 known seamounts, many of which originated at ________ centers.

volcanic