Oceanography chapter 4
neritic deposits
coarse grained, found in shallow water and near continents. lithogenous sediment dominates this type of sediment, and is found on the continental shelf, slope and rise. examples of this type of lithogenous sediment include continental shelf deposits, beach deposits, glacial deposits, and turbidite deposits
Which of the following contains calcium carbonate [CaCO3]? A. diatoms B. foraminiferans C. glauconite D. phosphorites E. radiolarians Answer B
foraminiferans
Where on the ocean floor do abyssal clays develop?
on the deep-ocean floor, far from land
marine sediment with more than 30% biogenous material is called oolite slime clathrate mud ooze
ooze
the most abundant mineral in lithogenous sediments is halite gypsum quartz aragonite calcite
quartz
of the following sediments which one is considered biogenous
radiolarian ooze test of foraminifiers
The presence of what type of macroscopic sediment would provide evidence of a meteorite impact on Earth? chondrites oolites tektites spherules micrometeorites
chondrites
What have oceanographers determined from analyzing sea floor cores?
climate change and past extinctions
marine sediments provide valuable clues about which of the following earth history events
previous ocean circulation patterns
Which of the following contains silica [SiO2]? A. coccolithophores B. corals C. foraminiferans D. phosphorites E. radiolarians Answer
radiolarians
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
marine sediments provide valuable clues about which of the following earth history events
the climate on earth millions of years ago
Which of the following materials would constitute biogenous sediment?
Microscopic shells Shark teeth Whale bones
What do manganese nodules, metal sulfides, and evaporites all have in common?
They all precipitate from water oversaturated in their respective minerals.
of the following sediments, which one is are considered hydrogenous
manganese nodules coatings of metal sulfides near black smokers
Two common types of chemical compounds found in biogenous sediments are __________ and __________.
Calcium carbonate; silica
Which of the following are examples of neritic sediments?
evaporate deposits Beach sand
Which of the following statements correctly interpret the environmental conditions associated with types of biogenous deposits? Choose all that apply.
Diatomaceous ooze on the sea floor indicat4es cool surface water above Foraminifer ooze on the sea floor means warm surface water above Coccolith ooze on the seafloor indicates the water is shallower than 4000 meters
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. (stromatolites, limestone, coccolithophores, diatoms, chalk)
Diatoms
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? Choose all that apply.
Previous ocean circulation patterns Past catastrophes, such as major extinction events The ancient geographical locations of ocean basins Movement of the ocean floor The climate on earth millions of years ago.
What is the limiting factor in determining the accumulation of siliceous ooze/calcareous ooze, respectively?
Productivity/water depth
Which of the following sediments would you expect to find in a lagoon?
Salt Broken bits of coral
How are seafloor sediments useful in reconstructing past ocean conditions?
Sediments that accumulate on the seafloor provide information about ocean conditions at the time that the sediment was deposited. Changes in the composition of the seafloor sediment reflect changes in the depositional environment.
What conditions are necessary for siliceous ooze to accumulate on the seafloor?
The surface waters must be nutrient-rich
What process allows siliceous organisms to thrive in areas along the equator?
Upwelling
Of the following types of lithogenous sediment, which one(s) would you expect to find very far from the location of origin? Choose all that apply.
Volcanic ash Quartz silt
Why do some organisms thrive in warm surface waters?
Warm water is generally saturated in carbonate.
Which sediment below cannot accumulate below the CCD?
Calcareous tests
Marine sediments that originate in the warm tropical surface ocean would create deposits in the deep sea composed primarily of ___________.
Calcium Carbonate
Which of the following are microscopic, single-celled floating algae that accumulate to form biogenous sediment?
-Coccolithophores -diatoms
Which of the following organisms are responsible for the creation of siliceous ooze?
-Radiolarians -Diatoms
What is the approximate depth of the calcite compensation depth (CCD) in the ocean?
3 miles(4.5 kilometers)
On average, at what ocean depth does calcite readily dissolve into seawater?
4500 meters (14,764 feet)
What is the expected calcium carbonate content in modern surface sediments at a latitude of 20 degrees north and a longitude of 20 degrees west?
50%-80% by weight
Which of the following conditions allows for calcareous ooze to exist beneath the CCD? Select only one answer.
A layer of clay buries the ooze before the sea floor subsides
Based on this data, choose the statement that offers the best explanation for the differences in sediment abundance between the North Atlantic and North Pacific basins.
Abyssal clays are more abundant in the North Pacific than the North Atlantic because calcareous oozes dissolve before reaching the sea floor in the latter ocean basin.
Where would you expect to find a high concentration of calcareous ooze?
Along the crest of mid-Atlantic ridge Surrounding Hawaii
Where might one find calcareous oozes on the seafloor?
Along the crests of mid-ocean ridges, above the CCD Buried beneath abyssal clay Buried beneath siliceous oozes
What factor primarily determines the distribution of radiolarian ooze?
Areas of upwelling
Why is this drilling process called rotary drilling?
Because the drill bit turns around in a circle.
Why does calcareous material dissolve below the CCD?
Below the CCD, weak acid is formed, which dissolves calcareous material.
Which of the following are examples of pelagic sediments?
Biogenic ooze Abyssal clay Volcanic dust
Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.
Biogenous
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.
What sediment type(s) is/are included in the pink category labeled "Other" on the map?
Cosmogenous sediments Hydrogenous sediments
Which of the following materials could form a siliceous ooze?
Diatoms Radiolarians Silicoflagellates
The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.
Diatoms; radiolarians
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.
Which of the following organisms thrive in cold surface waters?
Siliceous organisms Diatoms Radiolarians
In which of the following environments would you expect lithogenous sediment to be the dominant sediment type? Choose all that apply.
The abyssal plains At the base of the continental slope Along the mid-ocean ridge A sandy beach
Judge the following sentence according to the criteria given below: Microscopic biogenous ooze is common on the deep-ocean floor BECAUSE there is so little lithogenous sediment deposited at great distances from the continents that could dilute the biogenous material.
The assertion and the reason are both correct, and the reason is valid
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, the reason is valid
What can you infer about the ocean environment from a core sample composed of the following layers:
The core was collected in a region of high surface productivity in water deeper than 4,500 meters.
What factor primarily controls the distribution of calcareous ooze?
Water depth
in which of the following environment would you expect to find lithogenous sediment
at the base of the continental slope a muddy lagoon a sandy beach
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
neritic sediments are most likely to be composed of biogenic ooze red clay halite, gypsum, and anhydrite sand, silt and gravel, basalt fragments and metallic sulfides
sand, silt, and gravel
Of the following, which energy resource(s) can be extracted from marine sediments? Choose all that apply.
Gas hydrates Petroleum
What is calcareous ooze?
a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes
sediments with all grains of about the same size are classified as
well sorted
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
What is the expected calcium carbonate content in modern surface sediments at a latitude of 0 degrees and a longitude of 120 degrees west?
Greater than 80% by weight
What is the expected calcium carbonate content in modern surface sediments at a latitude of 20 degrees south and a longitude of 20 degrees west?
Greater than 80% by weight
What is the expected calcium carbonate content in modern surface sediments at a latitude of 60 degrees south and a longitude of 40 degrees east?
Less than 50% by weight
Sandstone is an example of which of the following sediment types?
Lithogenous sediment
Where would you expect to find a high concentration of siliceous ooze?
Neat the equator in areas of upwelling Off the coast of Alaska Surrounding Antarctica
Why doesn't siliceous ooze dissolve after it accumulates on the seafloor?
Once deposited on the seafloor, siliceous organisms bury each other
Which of the following factors affect the distribution of biogenic oozes on the seafloor?
Water depth Dissolution Seafloor spreading Biological productivity
What mechanism(s) is/are responsible for transporting clay to deep ocean basins?
Wind Slow-moving ocean currents
Which of the following conditions allow for calcareous ooze to be found beneath the CCD? Select only one answer. A.) Conditions of high salinity are present. b.) The deposit undergoes slow burial. c.) The ooze accumulates above the CCD and then is covered before being transported to deeper depths by sea floor spreading. D.) The deposit is mixed with hydrogenous sediment. E.) The calcareous ooze accumulates faster than it dissolves.
c.) the ooze accumulates above the CCD and then is covered before being transported to deeper depths by sea floor spreading
The sea floor provides the largest reservoir of usable energy in the ocean—and likely the world—in the form of ______________.
clathrates
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
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 is the correct order of sediment size from smallest to largest
clay, silt, sand, granule, pebble, cobble, boulder
You add sand, silt, and clay to a jar of water, shake the jar vigorously, and allow the sediment to settle. The resulting sediment will most closely resemble that of a(n) __________.
continental rise
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
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
oolites
Sediment samples from deep beneath the ocean floor are recovered by __________.
rotary drilling
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
siliceous ooze
What is the calcite compensation depth, or CCD?
the ocean depth below which calcite is unstable and will dissolve quickly
