Deck 5: Ocean Sediments

Question 1

A deep ocean ooze was discovered near Antarctica. What type is it likely to be?

A) Radiolarian ooze
B) Calcareous ooze
C) Diatom ooze
D) Foraminfera ooze

Answer 1

C
Diatom oozes occur at high latitudes in areas with seasonal upwelling. Although diatom and radiolarian oozes are both siliceous, radiolarian ooze tends to form in equatorial waters. Information can be found in the section Pelagic Sediments Vary in Composition and Thickness.

Question 2

What piece of equipment was able to facilitate the new fields of stratigraphy and paleoceanography with the data it generated?

A) Clamshell samplers
B) Deep water cameras
C) Piston Corers
D) Seismic profilers

Answer 2

C
The development of the piston corer allowed scientists to take samples from deep waters. The analysis of these cores led to the science of stratigraphy. Eventually, more information could be collected from these samples which eventually led to paleoceanography. Information can be found in the section Scientists Use Sensitive Tools to Study Ocean Sediments.

Question 3

Which is an example of an authigenic sediment?

A) Quartz sand
B) Manganese nodules
C) Volcanic dust
D) Diatomaceous earth

Answer 3

B
Authigenic sediments are also called hydrogenous sediments. These types of sediments are the results of chemical interactions with seawater. Information can be found in the section Sediments May be Classified by Source.

Question 4

What characterizes deep ocean sediments?

A) The sediments are well-sorted due to high energy fluctuations
B) The sediments are well-sorted due to low energy fluctuations
C) The sediments are poorly sorted due to high energy fluctuations
D) The sediments are poorly sorted due to low energy fluctuations

Question 5

If there is an abundance of foraminifera shells found in a sediment, it would be categorized as:

A) hydrogenous sediment.
B) calcareous ooze.
C) coccolithophore.
D) siliceous ooze.

Question 6

What is not considered a disruption to the normal sorting of the neritic sediments?

A) Glaciation
B) Turbidity currents
C) Wave action
D) Sea level changes

Question 7

Sometimes formations on land can shed light on ocean processes. What do the White Cliffs of Dover in England show?

A) An accumulation of very fine ooze of mixed origin that was pushed above sea level from plate tectonics.
B) An accumulation of siliceous ooze that has risen above sea level from plate tectonics.
C) A lithified calcareous ooze that was pushed above sea level from plate tectonics.
D) A sheared cliff that formed during sea floor spreading

Question 8

What is a main source of terrigenous sediments?

A) Volcanic eruptions
B) Rivers
C) Dust and ash
D) Cosmic dust

Question 9

What was the primary way sediment was transported to North America (east coast) continental margin during the last ice age?

A) Rivers carry the sediment right to the shelf edge.
B) Strong currents carry the sediment to the contential shelf edge.
C) Wind blows sediment from the continent to the shelf edge
D) Glaciers

Question 10

What organism is likely to be found in siliceous ooze?

A) Foraminifera
B) Coccolithophore
C) Radiolarian
D) Pteropod

Question 11

What kind of sediments are igneous rocks associated with?

A) Terrigenous
B) Biogenous
C) Hydrogenous
D) Cosmogenous

Question 12

If a sediment is white in color, it is likely to be:

A) undergoing oxidation.
B) terrigenous in origin.
C) biological in origin.
D) a nodular sediment.

Question 13

What is one reason diatomaceous earth is economically valued?

A) It can be used as a fossil fuel alternative.
B) It can be used for various filtration systems.
C) It can be broken up for gravel and used as building materials.
D) It demonstrates the presence of "marine snow."

Question 14

The ____ has/have a low ratio of volume in comparison to its area in the ocean.

A) Continental shelves
B) Submarine canyons
C) Continental rises
D) Deep ocean floor

Question 15

The sediments that occur on the slope, rise, and deep ocean floor and originate in the ocean are called:

A) neritic sediments
B) pelagic sediments
C) terrigenous sediments
D) well-sorted sediments

Question 16

What is an example of terrigenous sediment?

A) Diatomaceous earth
B) Manganese nodules
C) Oolite sand
D) Quartz

Question 17

What statement is true of biogenous and terrigenous sediments?

A) Biogenous sediments comprise a larger area than terrigenous sediments.
B) Biogenous sediments cover more volume than terrigenous sediments.
C) Terrigenous sediments make up a larger area than biogenous sediments.
D) Terrigenous and biogenous sediments are equal in area and volume.

Question 18

What kind of information can marine microfossils not provide?

A) Temperature variations in the surface and deep water.
B) Patterns in ocean circulation
C) The orientation of the magnetic poles based on trace metals found within the shells
D) Productivity of the marine biosphere and upwelling

Question 19

The west coast of South America is known for its seasonal upwelling. What kind of sediment is likely to be abundant based on this information?

A) Terrigenous
B) Hydrogenous
C) Biogenous
D) Cosmogenous

Question 20

An area is found to have a high rate of erosion. What kind of sediment is likely to be in the surrounding waters?

A) Well-sorted sediments
B) Poorly-sorted sediments
C) One size of sediment
D) Course grained sediments

Question 21

The increased presence of carbonic acid at deep depths causes calcium carbonate to precipitate into a solid beneath approximately 4500 meters.

Question 22

Most sediments have a composition derived from a mixture of origins.

Question 23

Which is not a common particle size for most marine sediments?

A) Clay
B) Silt
C) Sand
D) Pebbles

Question 24

Which statement describes turbidites?

A) They are graded layers of terrigenous sand mixed with finer pelagic sediments.
B) They are propelled into position by gravity rather than water currents.
C) They are composed of distinct layers that represent various turbidity current events.
D) All of these choices are true about turbidites.

Question 25

Which sediment is categorized under cosmogenous sediments?

A) Evaporites
B) Ooliths
C) Microtektites
D) Manganese nodules

Question 26

What is the calcium carbonate compensation depth?

A) The depth at which calcium carbonate begins to precipitate into a solid.
B) The depth at which a calcareous ooze can start forming.
C) The depth at which calcium carbonate starts to dissolve.
D) The depth at which seawater becomes less acidic.

Question 27

Both basalt and granite are examples igneous rocks.

Question 28

What valuable commodity has yet to be commercially mined from ocean sediments?

A) Natural gas
B) Gravel
C) Diatomaceous earth
D) Manganese nodules

Question 29

Most near shore sediments smell of hydrogen sulfide due to high levels of decomposing organic matter.

Question 30

Lithification is a process that is often pressure induced.

Question 31

Even in a rare area in which there are no overlying sediments, there are sediments found in the water above.

Question 32

Calcareous oozes form much slower than siliceous oozes based on the rate their components dissolve in seawater.

Question 33

What can cause hydrogenous calcium carbonate deposits?

A) Evaporation
B) A decrease in the acidity of seawater
C) An increase in seawater temperature
D) All of these choices

Question 34

In addition to information gained from stratigraphy, what contributed to the emergence of paleoceanography?

A) Seismic profiling
B) The identification of various oozes
C) The advent of deep sea drilling
D) Paleomagnetic dating

Question 35

Approximately how much of the world's estimated oil and gas reserves can be found within the sediments of the continental margins?

A) One-third
B) One-half
C) Two-thirds
D) Three-quarters

Question 36

What is often found in the middle of manganese nodules?

A) Microtektites
B) Shark teeth or bone fragments
C) Living bacteria
D) Sand grains

Question 37

Clays can remain suspended in a water column for decades before settling due to their small size.

Question 38

What explains why the ocean's sedimentary "memory" or record does not start with the ocean's formation?

A) Samples cannot be attained in deep water.
B) Ocean sediment records are destroyed by subduction.
C) No sediments deposit when new ocean basins form
D) Sediments are buried deep and are eventually metamorphosed

Question 39

The compression of small biological particles into fecal pellets increases the rate at which they sink to the bottom.

Question 40

Although most of biological productivity occurs close to land, a greater proportion is found in pelagic sediments.

Question 41

Compare the thickness of pelagic sediments in the Pacific Ocean to that of the Atlantic. What reasons account for the differences? Using information from Chapter 4, would the type of margin have an effect? Why or why not?

Question 42

The Pacific has a thinner layer of pelagic sediments than the Atlantic due to fewer rivers and an increase in trenches.

Question 43

Define well-sorted and poorly sorted sediments. What is expected on the deep ocean floor? Which is found close to shore? Include information about the energy associated with each and the avenues of transportation of these sediments.

Question 44

Paleoceanography analyzes layered sedimentary deposits to trace distinctive layers while establishing the ages of these deposits.

Question 45

What is the distribution of neritic sediments, by size, from the shoreline outward towards the deep ocean? What facilitates the movement of each size of sediment?

Question 46

Manganese and phosphorite nodules can only be observed in areas of high sediment accumulation.

Question 47

What are manganese nodules? How are they formed? Using the information regarding the usefulness of these nodules, can you infer why the mining of these nodules could become a political issue?

Question 48

Neritic sediments are mainly comprised of biogenous sediments due to the proximity to the continental shelf.

Question 49

Why is the study of sediments so important? What kind of information can be discovered by studying sediments? How have tools and equipment evolved to expand the study of sediments?

Question 50

Biological sediments are the most abundant sediments due to the high productivity of organisms along the continental shelf.