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