OCE1001 Ch 4

Which of the following is not an important control on oceanic sediment accumulation?

All of the above: rate of deposition degree of preservation input from other sediment types dilution

Coccolithophores

Bigenous sediment

Beneath the calcite compensation depth (CCD), ___________.

Calcium carbonate dissolves in seawater

Because they tend to move downslope, most lithogenous sediments are deposited in abyssal plains

False

Black volcanic beach sand is a type of hydrogenous sediment.

False

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

False

The Wentworth scale is used to arrange the amount of sorting in a sediment deposit

False

The deposition of radiolarian oozes is affected by the carbonate compensation depth.

False

the calcite compensation depth represents the depthe where wave action ceases to form calcareous oolites

False

Which of the following contains CaCO3?

Foraminiferans

In sediments, what does the Wentworth scale describe?

Grain size

All of the following are examples of sediment transporting media except

Levitation

Describe the origin, composition, texture and distribution of lithogenous sediment

Lithogenous sediment is derived from pre-existing rock that is weathered and transported to the oceans by streams, wind, glaciers, and gravity from land. The composition reflects the material from which it was derived. The size is dependent on the energy needed to lay down the deposit, as well as its sorting. It can be found nearly everywhere on the ocean floor

What is the difference between neritic and pelagic deposits?

Neritic (of the coast) deposits are found on continental shelves and in shallow water near islands; these deposits are generally coarse grained. Pelagic (of the sea) deposits are found in the deep ocean basins and are typically finer grained material

List the two major chemical compounds that comprise most biogenous sediment, as well as examples of the organisms that produce them.

The 2 most common chemical compounds in biogenous sediment are calcium carbonate (produced by foraminifers and coccolithophores) and silica (produced by diatoms and radiolarians)

Oozes are uncommon on continental margins because

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

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 of seafloor spreading

All of the following are true concerning neritic sediment deposits except:

They are primarily composed of calcareous deposits of biological origin

Describe the process of how a deep-sea drilling agent such a the JOIDES Resolution obtains core samples from the deap ocean floor

This ship has a tall metal drilling rig to conduct rotary drilling. The drill pipe is made up of individual sections that can be screwed together to make a single string of pipe. The drill bit, located at the end of the pipe string, rotates as it is pressed against the ocean bottom. A core can then be raised to the surface from inside the pipe.

The only way for siliceous ooze to be preserved in the ocean is ___________.

To have it accumulate faster than it dissolves

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

The organisms that contribute to biogenous sediment are chiefly algae an protozoans

True

Where are most modern day calcaeous oozes found in the ocean

along the mid ocean ridge beneath warm surface waters

ice rafting

associated with glacial deposits

Turbidite

associated with submarine canyons and deep-sea alluvial fans

Which of the following statements about bigenous oozes is false

biogeneous oozes are created by underwater eruptions, which cover the seafloor with fine ash particles

Siliceous ooze

biogenous sediment

How is most sediment transported from the continental shelf out to the continental rise

by turbidity currents

Which of the following is the most abudant component by weight for deep-ocean sediments

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

Ocean sediments proved all of the following mineral resources except

coal

Tektites

cosmogenous

Halite

hydrogenous sediment

metal sulfides

hydrogenous sediment

Salt beds of the US Gulf Coast are

hydrogenous sediments

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

in deep trenches not far offshore

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

less than 30% biogenous material

Sediments derived from pre-existing rocks on land are called

lithogenous

Sediment that begins as rocks on continents or islands is called

lithogenous (terrigenous) sediment

CaCO3 is most likely to dissolve in water with which characteristics

lots of CO2 and colder temperatures

Lithogenous sediments are

made of material derived from pre-existing rock material

Which of the following statements about manganese nodules is false

they are a type of foraminifer

Calcerous ooze is associated with ______ surface water conditions, and siliceous oooze is associated with _____ surface conditions

warm; cool

Sediments with grains of about the same size are classified as

well sorted

Sediments that are poorly sorted were most likely deposited by

a glacier

which of the following is the most fine grained sediment

abyssal clay

The most likely place to fin abudant manganese nodules is on the

abyssal plain far from a continent

Most chalk is made from

coccoliths

Populations of microscopic marine organisms in ocean surface waters closely match their abundance in sediments on the ocean floor, even though it takes 10 to 50 years for an individual particle to sink to deep-ocean depths. What accounts for this pattern?

concentration of the particles in fecal pellets

Sediments with an extraterrestrial origin are called:

cosmogenous

Which of the following marine organisms live in cold, polar waters

diatomrs

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

diatoms

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

manganese nodules

Sediments found on continental margins are called

neritic

The most abundant mineral in lithogenous sediments is

quartz

All of the following are hydrogenous sediments except

stromatolites

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

tektites

Microscopic shells that create biogenous sediment on the seafloor are called

tests

Which of the following statements about the DSDP is false

the DSDP drilled to the center of Earth and confirmed that the outer core is composed of liquid iron-nickel material

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

the ancient geographical locations of ocean basins