OCE ch 4 – Flashcards
Flashcard maker : Steven Ramirez
Marine sediments that originate in the warm tropical surface ocean would create deposits in the deep sea composed primarily of ___________.
calcium carbonate
Ocean sediments consist of particles that have slowly settled out of the water by which of the following the processes?
Suspension settling
What percentage of the rocks exposed on the continents originated as sedimentary rocks deposited in ancient ocean environments?
More than fifty percent
Collecting adequate samples from which of the following is the most difficult?
The deep-ocean floor
Which of the following is a hollow steel tube with a heavy weight on top that is to collect sediment samples?
Gravity core
Which of the following is the most advanced technology used to collect sediment samples from the deep ocean?
Rotary corer
Marine sediments provide valuable clues about which of the following Earth history events?
the climate on Earth millions of years ago, movement of the ocean floor, previous ocean circulation patterns, past catastrophes, such as major extinction events, the ancient geographical locations of ocean basins
Why is this drilling process called rotary drilling?
Because the drill bit turns around in a circle,
What common household item is used in this video to demonstrate rotary drilling?
an apple corer
What have oceanographers determined from analyzing sea floor cores?
climate change and past extinctions
High-energy environments are most likely to deposit which one of the following?
large particles such as gravel
Sediments that are poorly sorted were most likely deposited by:
a glacier.
Sediments derived from pre-existing rocks on land are called:
lithogenous
Sandstone is an example of which of the following sediment types?
Lithogenous Sediment
Terrigenous sediment is another name for which of the following?
Lithogenous Sediment
Shale is an example of which of the following sediment types?
Lithogenous Sediment
Turbidite deposits are an example of which of the following sediment types?
Lithogenous Sediment
Abyssal clay is an example of which of the following sediment types?
Lithogenous Sediment
Glacial deposits are an example of which of the following sediment types?
Lithogenous Sediment
From smallest to largest, which list of sediment particle sizes is in the correct order?
clay, silt, sand, pebbles
Of the following types of lithogenous sediment, which one(s) would you expect to find very far from the location of origin?
Volcanic ash, Quartz silt
Sediments produced by plants and animals in the sea are called:
biogenous
Siliceous ooze is an example of which of the following sediment types?
Biogenous Sediment
Calcareous ooze is an example of which of the following sediment types?
Biogenous Sediment
The number of organisms present in the surface water above the ocean floor is called ________.
productivity
Which of the following are microscopic, single-celled floating algae that accumulate to form biogenous sediment?
Diatoms, Coccolithophores
What is calcareous ooze?
a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes
What is the calcite compensation depth, or CCD?
the ocean depth below which calcite is unstable and will dissolve quickly
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
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 is the approximate depth of the calcite compensation depth (CCD) in the ocean?
3 miles (4.5 kilometers)
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
does not dissolve; does not dissolve
Why does calcareous material dissolve below the CCD?
Below the CCD, weak acid is formed, which dissolves calcareous material.
Which of the following organisms thrive in cold surface waters?
diatoms, siliceous organism, radiolarians
Why do some organisms thrive in warm surface waters?
Warm water is generally saturated in carbonate
Where might one find calcareous oozes on the seafloor?
buried beneath abyssal clay, along the crests of mid-ocean ridges, above the CCD, buried beneath siliceous oozes
Which of the following factors affect the distribution of biogenic oozes on the seafloor?
biological productivity,water depth,dissolution,seafloor spreading
On average, at what ocean depth does calcite readily dissolve into seawater?
4500 meters (14,764 feet)
On the world ocean pie diagram, list the sediment types from largest to smallest
Calcareous ooze, siliiceous ooze, Abyssal clay
Sediments produced because of chemical reactions in seawater are called
hydrogenous
The most likely place to find abundant manganese nodules is on the
abyssal plain far from a continent
Oolites are an example of which of the following sediment types?
Hydrogenous Sediment
Rock salt (halite) is an example of which of the following sediment types?
Hydrogenous Sediment
Of the following sediments, which one(s) is/are considered hydrogenous?
coatings of metal sulfides near black smokers, manganese nodules
Sediments with an extraterrestrial origin are called
cosmogenous
Micrometeorites are an example of which of the following sediment types
Cosmogenous Sediment
A very important way to increase the settling rate of fine particles in the open ocean is via
fecal pellets.
The type of marine sediment that forms the thickest deposits worldwide is
neritic, lithogenous sediment deposits
Neritic sediments are most likely to be composed of __________.
sand, silt, and gravel
Which sediment type dominates in the neritic environment?
coarse lithogenous sediment, such as sand and small rocks
What factor primarily controls the distribution of calcareous ooze?
water depth
What factor primarily determines the distribution of radiolarian ooze?
areas of upwelling
What mechanism(s) is/are responsible for transporting clay to deep ocean basins?
wind
Which of the following are examples of neritic sediments?
beach sand, evaporite deposits
Where on the ocean floor do abyssal clays develop?
on the deep-ocean floor, far from land
Which of the following sediments would you expect to find in a lagoon?
broken bits of coral, salt
Which of the following are examples of pelagic sediments?
abyssal clay, volcanic dust, biogenic ooze
Which sediment below cannot accumulate below the CCD?
calcareous tests
The sea floor provides the largest reservoir of usable energy in the ocean, and likely the world, in the form of ______________.
clathrates
The main energy resources associated with marine sediments are petroleum and ________.
gas hydrates
Which of the following contains the most organic carbon on Earth?
Gas hydrates
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 natural gasses is most common in gas hydrates from under the ocean floor?
Methane
Of the following, which energy resource(s) can be extracted from marine sediments?
Petroleum, Gas hydrates
