Chapter 4
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 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.
Where might one find calcareous oozes on the seafloor? Choose all that apply.
buried beneath siliceous oozes buried beneath abyssal clay along the crests of mid-ocean ridges, above the CCD.
Which of the following factors affect the distribution of biogenic oozes on the seafloor? Choose all that apply.
dissolution biological productivity water depth seafloor spreading
Forams, which are composed of calcium carbonate, __________ above the CCD and __________ below the CCD.
do not dissolve; dissolve
Which of the following organisms thrive in cold surface waters? Choose all that apply.
radiolarians siliceous organisms diatoms
Which of the following materials would constitute biogenous sediment? Choose all that apply.
shark teeth microscopic shells whale bones
Which of the following materials could form a siliceous ooze? Choose all that apply.
silicoflagellates radiolarians diatoms
