Oceanography Ch. 4

What is the approximate depth of the calcite compensation depth (CCD) in the ocean?

3 miles (4.5 kilometers)

Why does calcareous material dissolve below the CCD?

Below the CCD, weak acid is formed, which dissolves calcareous material.

Fossiliferous limestone is an example of which of the following sediment types?

Biogenous Sediment

The White Cliffs of Dover are an example of which of the following sediment types?

Biogenous Sediment

Judge the following sentence according to the criteria given below: Biogenous sediment usually contains abundant calcite below the calcite compensation depth BECAUSE it readily dissolves above the calcite compensation depth.

Both the assertion and the reason are incorrect.

What would happen if the depth of the CCD were above the top of the mid-ocean ridge?

Calcareous ooze would not be found below the CCD.

Tektites are an example of which of the following sediment types?

Cosmogenous Sediment

Which of the following is thought to have enriched ocean floor sediments with rare-earth elements?

Deep-sea hotsprings

Which of the following marine resources is used to make wallboard or sheet rock?

Evaporative salts

Of the following, which energy resource(s) can be extracted from marine sediments? Choose all that apply.

Gas hydrates; Petroleum

Oolites are an example of which of the following sediment types?

Hydrogenous Sediment

Turbidite deposits are an example of which of the following sediment types?

Lithogenous Sediment

Which of the following natural gasses is most common in gas hydrates from under the ocean floor?

Methane

The ancient remains of which of the following, buried before they could decompose, are the source of today's petroleum deposits?

Microscopic organisms

Which of the following resources found in ocean sediments has the greatest economic value?

Petroleum

China currently supplies about 90% of which of the following resources?

Rare-earth elements

Judge the following sentence according to the criteria given below: An increase in atmospheric carbon dioxide due to the burning of coal will cause the calcite compensation depth to rise BECAUSE the oceans will get more acidic.

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

Judge the following sentence according to the criteria given below: Abyssal clays are commonly red-brown or buff in color BECAUSE they contain gypsum.

The assertion is correct, but the reason is incorrect.

Judge the following sentence according to the criteria given below: Marine sediments can't provide insight into today's climate changes BECAUSE they reveal a detailed history of Earth's past climate.

The assertion is incorrect, but the reason is correct.

Which of the following contains calcium carbonate (CaCO3)?

foraminiferans

The main energy resources associated with marine sediments are petroleum and ________.

gas hydrates

In general, polar neritic sediment tends to have more ________.

gravel than in tropical waters

Siliceous ooze is particularly abundant on the seafloor at __________ and at __________.

high latitudes; equatorial upwelling zones

Salt beds of the U.S. Gulf Coast are __________.

hydrogenous sediments

Sandstone is an example of which of the following sediment types?

Lithogenous Sediment

How does siliceous ooze accumulate on the seafloor if silica-based residues are dissolved slowly at all depths?

Silica tests accumulate faster than seawater can dissolve them.

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.

Siliceous ooze

Which of the following statements about marine sediments is correct?

They record the timing and severity of some global extinction events.

calcareous

a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes

The most likely place to find abundant manganese nodules is on the:

abyssal plain far from a continent.

What factor primarily determines the distribution of radiolarian ooze?

areas of upwelling

In which of the following environments would you expect lithogenous sediment to be the dominant sediment type?

at the base of the continental slope; a sandy beach; along the mid-ocean ridge; the abyssal plains

Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.

biogenous

Two common types of chemical compounds found in biogenous sediments are __________ and __________.

calcium carbonate; silica

You take a sediment sample from the ocean floor at a depth of 5500 m. The area has low biological productivity and the CCD is at 4500 m depth. Your sample will probably consist of __________.

clay

What have oceanographers determined from analyzing sea floor cores?

climate change and past extinctions

Which sediment type dominates in the neritic environment?

coarse lithogenous sediment, such as sand and small rocks

Calcite dissolves more readily in seawater that is ________ in temperature and ________ in pressure.

colder; higher

Sediments with an extraterrestrial origin are called:

cosmogenous

What three steps are required for calcareous ooze to exist below the CCD?

deposition of calcite shells above the CCD, cover of these shells by a non-calcareous material, and movement of the sea floor over millions of years

The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.

diatoms; radiolarians

The deposition of coarse-grained lithogenous material in neritic environments along continental margins is an example of the ________ of biogenous sediment.

dilution

Forams, which are composed of calcium carbonate, __________ above the CCD and __________ below the CCD.

do not dissolve; dissolve

Diatomaceous earth, which is composed of silica, __________ above the CCD and __________ below the CCD.

does not dissolve; does not dissolve

Which of the following was used during early exploration of the oceans to collect sediment samples?

dredge

Shortly after the devastating 2011 Tohoku-Oki Earthquake, the Chikyu drillship began an expedition to study which of the following?

earthquake-generated heat from friction

A very important way to increase the settling rate of fine particles in the open ocean is via:

fecal pellets.

What sediment type(s) is/are included in the pink category labeled "Other" on the map?

hydrogenous sediments; cosmogenous sediments

Sediments produced because of chemical reactions in seawater are called:

hydrogenous.

Sediments derived from pre-existing rocks on land are called:

lithogenous.

Calcium carbonate is most likely to dissolve in water with which characteristic?

low salinity

Of the following sediments, which one(s) is/are considered hydrogenous?

manganese nodules; coatings of metal sulfides near black smokers

The most abundant mineral in lithogenous sediments is __________.

quartz

Which of the following is the most advanced technology used to collect sediment samples from the deep ocean?

rotary corer

Neritic sediments are most likely to be composed of __________.

sand, silt, and gravel

What mechanism(s) is/are responsible for transporting clay to deep ocean basins?

slow-moving ocean currents; wind

The particles found in some sediment that suggests that an extraterrestrial impact event are:

tektites

Collecting adequate samples from which of the following is the most difficult?

the deep-ocean floor

What is the calcite compensation depth, or CCD?

the ocean depth below which calcite is unstable and will dissolve quickly

What factor primarily controls the distribution of calcareous ooze?

water depth