Oceanography Chapter 3

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

Precipitation

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).

Volcanic features on the ocean floor that are less than 1,000 meters (0.6 miles) tall are called:

Seaknolls

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

Seamounts

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

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 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 byssal 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).

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

Suspension setting

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 past the continental slope.

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

What is the advantage(s) of a multi-beam sounder compared to traditional echo sounding?

-provides a swath of measurements with each sweep of the seafloor -provides info about seafloor composition -more detailed -more accurate

What feature(s) can be recognized using multi-beam sonar?

-ridge axis, tablemount, shipwreck, seamount

Of the following statements about Earth's hypsographic curve, which is/are true?

-the hypsographic curve shows that the average depth of the ocean floor is about 4 times the average height of continents -they hypsographcic curve shows the percentage of Earths surface area is covered by ocean waters -shows that a majority of the ocean floor is more than 4 kilometers deep -shows that a majority of the exposed land is below 11 meters in elevation

Characteristics of passive continental margins include which of the following?

Broad continental shelves

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

Continental rifting and continued sea floor spreading

Where would you expect to find graded bedding?

Deep sea fans

Active continental margins are characterized by which of the following?

Deep-sea trenches

Older lithosphere is destroyed in association with:

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

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 a volcanic island associated with volcanic activity at a ___________.

Hotspot

Graded bedding provides evidence that ____________.

Large, heavy particles settle out first as current velocity decreases.

To which planet is NASA sending the spacecraft insight to study crustal movements similar to earthquakes?

Mars

In a linear seafloor fracture that has the following properties: a transform fault, a fracture zone, or neither? It 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?

Neither

Is a linear seafloor fracture that has the following properties a transform fault, a fracture zone, or neither?it is seismically active, 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?

Niether

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

Ocean rises

Why is the average depth of the ocean much greater than the average heigh of land?

Oceanic crust is more dense that continental crust

New lithosphere is produced in association with:

Oceanic ridges

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

Oceanic trenches

Deep-ocean tenches 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

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

Perpendicular to the ridge axis

Most large ocean floor features owe their origins to _________.

Plate tectonic processes

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

Satellites are used to map the ocean floor because:

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

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

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

Transform fault

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

Turbidity currents

Measurement of ocean floor bathymetry from satellites relies on ___________.

sea surface elevation, which varies depending on the slope of the underlying seafloor.

Of the following items which is/are associated with a passive continental margin?

- a wide continental shelf - a continental rise

Of the following techniques, which one(s) can be used to map the sea floor?

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

Sediments deposited by the process of suspension settling produce the majority of sediment found on_________.

Abyssal plains

Why is Greenland currently an area of active seafloor research?

-deep ocean currents cause coastal glacier to melt -coastal water depths surrounding Greenland have not yet been well documented

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

85%

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

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

Abyssal plains

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

At convergent plate boundaries

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

Bathymetry

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

Continental slope

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

Continental slope

Trenches are typically associated with ________.

Convergent continental margins

Oceanic ridges and rises result from seafloor spreading along:

Divergent plate boundaries

Relatively few abyssal plains are located in the pacific ocean due to:

The presence of convergent active margins

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

The shallowest slope below sea level

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

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

White smokers

What is bathymetry?

the study of the depth of the ocean