Oceanography-Chapter 4
Diatomaceous earth, which is composed of silica, __________ above the CCD and __________ below the CCD.
does not dissolve; does not dissolve
Which of the following statements about the ccd is corrext
Below the ccd physical conditions cause calcium carbonate to dissolve
Where is calcareous ooze most likely to be found in surface sediments in the ocean
Relatively shallow areas with warm surface water
Where do calcareous oozes exist on the sea floor
Underneath areas where calcareous organisms live but above the ccd
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.
Two common types of chemical compounds found in biogenous sediments are
Calcium carbonate and silica
What is calcareous ooze?
a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes
What is the approximate depth of the calcium compensation depth ccd in the ocean
3 miles, 4.5 km
What is calcareous ooze composed of
At least 30% the remains of calcareous organisms
Why does calcareous material dissolve below the CCD?
Below the CCD, weak acid is formed, which dissolves calcareous material.
Sediments derived from the remains of once living organisms are called
Biogenous sediments
Which of the following explains why calcareous ooze is sometimes found below the ccd
Calcareous ooze can be deposited above the veg and covered with other sediment which protects it as the tectonic plate moves it into deeper water
The two major types of microscopic planktonic organisms that produce siliceous oozes are
Diatoms and radiolarians
The tests from which of the following organisms will dissolve below the ccd
Foraminifera and coccolithophores
What conditions exist below the ccd
High acidity, Cold temp, high carbon dioxide consentration
Which setting would calcareous ooze be most likely to form
On the crest of a seamount under warm surface water
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.
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
Forams, which are composed of calcium carbonate, __________ above the CCD and __________ below the CCD.
do not dissolve; dissolve
Siliceous ooze is particularly abundant on the seafloor at __________ and at __________.
high latitudes; equatorial upwelling zones
What is the calcite compensation depth, or CCD?
the ocean depth below which calcite is unstable and will dissolve quickly
