OCE Ch.4

Why does calcareous material dissolve below the CCD?

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

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.

Which of the following organisms are responsible for the creation of siliceous ooze?

-Diatoms -Radiolarians

Which of the following conditions allows for calcareous ooze to be found beneath the CCD? Select only one answer.

-The ooze accumulates above the CCD and then is covered before being transported to deeper depths by sea floor spreading.

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. coccolithophores B. diatoms C. foraminiferans D. oolites E. radiolarians

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. halite and other salts B. manganese nodules C. metal sulfides D. phosphates E. tektites

E

Calcareous ooze is found in cooler waters at depth around the world.

False

Radiolarian tests are dissolved beneath the carbonate compensation depth.

False

Under what conditions will the front of a glacier remain stationary?

Glacial fronts remain stationary when melting and snow accumulation are equal.

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

What is salt weathering?

The formation of minerals in rock cracks during the evaporation of salty water, forcing rock apart.

How would you expect the front of a glacier to move if it undergoes a period of net accumulation, followed by net wastage, and finally a period of net accumulation?

The glacier's front would move forward, backward, and then forward again.

How would a snow line on a glacier move as a glacial front is advancing?

The snow line would move downslope.

What do manganese nodules, metal sulfides, and evaporites all have in common?

They all precipitate from water oversaturated in their respective minerals.

Coastal sand dunes are usually well sorted due to winds.

True

Organisms that live on the ocean floor may be responsible for keeping manganese nodules from being buried in the sediment.

True

Tektites are glassy rock fragments created during impact events.

True

Texture refers to the size and shape of sediment particles.

True

Why does water frozen in the cracks of a rock help to break down the rock?

Water expands when frozen and physically forces the rock apart.

What is calcareous ooze?

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

Sediments that are poorly sorted were most likely deposited by:

a glacier.

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

abyssal plain far from a continent.

ice rafting

associated with glacial deposits

turbidite

associated with submarine canyons and deep-sea alluvial fans

coccolithophores

biogenous sediment

The depth at which calcite dissolves rapidly in the ocean is called the __________.

calcite compensation depth or CCD

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

calcium carbonate; silica

Carbon dioxide (CO2) combines with water (H2O) to form __________.

carbonic acid (H2CO3)

Complete this analogy: Bouncing is to sand as suspension is to_____________.

clay

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

Ocean sediments provide all the following mineral resources except :

coal.

tektites

cosmogenous sediment

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

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 way does ice flow in a glacier retreating uphill?

downslope

Complete this analogy: Sliding is to gravel as dissolution is to_____________.

ions

Pelagic clays contain lots of material that settles to the seafloor through the water column and are:

less than 30% biogenous material.

Sediment that begins as rocks on continents or islands is called:

lithogenous (terrigenous) sediment.

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

Sediments found on continental margins are called:

neritic.

The most abundant mineral in lithogenous sediments is __________.

quartz

How can pieces of rock in contact with a stream bed move?

rolling, sliding, bouncing

All the following are examples of hydrogenous sediment except :

stromatolites.

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

tektites.

Oozes are uncommon on continental margins because __________.

the biogenous component tends to be overwhelmed by the amount of lithogenous material derived from the nearby continent

Which is the best definition of glacial snow line?

the line dividing zones of accumulation and melting of ice at the surface of a glacier

All the following are true concerning neritic sediment deposits except :

they are primarily composed of calcareous deposits of biological origin.

Sediments with all grains of about the same size are classified as __________.

well sorted

As a whole, the pH of surface waters of the ocean is slightly __________.

-alkaline

What are the three types of loads carried by streams?

-bed load, suspended load, dissolved load

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

-biogenous

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

-coatings of metal sulfides near black smokers -manganese nodules

Calcite-secreting organisms such as __________ and __________ live in the ocean's sunlit surface waters and form the basis of most marine food webs.

-coccolithophores; foraminifers

Which of the following are part of the bed load?

-gravel -sand

Of the following environments, where would you expect to find large amounts of lithogenous sediment?

-on the continental shelf -in deep trenches not far offshore

A sediment sample dominated by microscopic lithogenous sediment grains would be classified as a ___________.

-pelagic deposit

Marine sediments provide valuable clues about which of the following Earth history events?

-the climate on Earth millions of years ago -previous ocean circulation patterns -the ancient geographical locations of ocean basins -movement of the ocean floor -past catastrophes, such as major extinction events

What is suspended load?

-the fine-grained particles that travel in the water column above the stream bed

What is the calcite compensation depth, or CCD?

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

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

3 miles (4.5 kilometers)

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. siliceous ooze B. quartz sand C. rock fragments D. clay E. volcanic ash

A

What do freeze-thaw and salt weathering have in common?

Both freeze-thaw and salt weathering require rain and force rocks apart physically.

siliceous ooze

biogenous sediment

Which of the following contains calcium carbonate (CaCO3)?

foraminiferans

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

high latitudes; equatorial upwelling zones

The pH scale is a measure of the __________ ion concentration of a solution.

hydrogen

halite

hydrogenous sediment

metal sulfides

hydrogenous sediment

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

hydrogenous sediments