oceanography chapter 4
What is the limiting factor in determining the accumulation of siliceous ooze/calcareous ooze, respectively?
productivity/water depth
Which of the following organisms thrive in cold surface waters?
radiolarians, siliceous organisms & diatoms
Which of the following materials would constitute biogenous sediment?
shark teeth, microscopic shells & whale bones
What mechanism(s) is/are responsible for transporting clay to deep ocean basins?
slow-moving ocean currents & wind
Where would you expect to find a high concentration of calcareous ooze?
surrounding Hawaii & along the crest of the Mid-Atlantic Ridge
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
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.
Why do some organisms thrive in warm surface waters?
Warm water is generally saturated in carbonate
Which of the following are examples of neritic sediments?
beach sand & evaporite deposits
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)
Why does calcareous material dissolve below the CCD?
Below the CCD, weak acid is formed, which dissolves calcareous material.
Why doesn't siliceous ooze dissolve after it accumulates on the seafloor?
Once deposited on the seafloor, siliceous organisms bury each other.
What factor primarily determines the distribution of radiolarian ooze?
areas of upwelling
Where might one find calcareous oozes on the seafloor?
buried beneath siliceous oozes, buried beneath abyssal clay & along the crests of mid-ocean ridges, above the CCD
Which sediment below cannot accumulate below the CCD?
calcareous tests
Which sediment type dominates in the neritic environment?
coarse lithogenous sediment, such as sand and small rocks
Which of the following materials could form a siliceous ooze?
diatoms, silicoflagellates & radiolarians
What sediment type(s) is/are included in the pink category labeled "Other" on the map?
hydrogenous sediments & cosmogenous sediments
Where would you expect to find a high concentration of siliceous ooze?
near the equator in areas of upwelling, off the coast of Alaska & surrounding Antarctica
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?
sald & broken bits of coral
What process allows siliceous organisms to thrive in areas along the equator?
upwelling
Which of the following are examples of pelagic sediments?
volcanic dust, biogenic ooze & abyssal clay
What factor primarily controls the distribution of calcareous ooze?
water depth
Which of the following factors affect the distribution of biogenic oozes on the seafloor?
water depth, biological productivity, dissolution & seafloor spreading