Chapter 04: Marine Sediments

Two common types of chemical compounds found in biogenous sediments are __________ and __________.

calcium carbonate; silica

What is calcareous ooze?

a fine-grained, deep ocean sediment containing the skeletal remains of calcite-secreting microbes

Part complete 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

The tests from which of the following organisms will dissolve below the CCD? Choose all that apply.

- coccolithophores - foraminifera

What conditions exist below the CCD? Choose all that apply.

- high acidity - cold temperature - high carbon dioxide concentration

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer

1. B: Radiolarian, showing long appendagestarget 2. D: Diatom, top viewtarget 3. C: Radiolarian, spherical shapetarget 4. A: Diatom, showing both halves of its test

Which of the following statements about the calcite compensation depth (CCD) is correct?

Below the calcite compensation depth (CCD), physical conditions cause calcium carbonate to dissolve.

Where do calcareous oozes exist on the seafloor?

Underneath areas where calcareous organisms live, above the CCD.

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. A: Coccolithophores (multiple)target 2. C: Coccoliths (individual plates)target 3. B: Foraminiferstarget 4. D: Coccolithophore (single)target 5. E: Diatom (siliceous)

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. A: Siliceous ooze: diatomtarget 2. E: Siliceous ooze: radiolariantarget 3. D: Calcareous oozetarget 4. B: Abyssal claytarget 5. C: Neritic continental lithogenous

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. B: Calcareous oozetarget 2. A: Abyssal claytarget 3. C: Siliceous ooze

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. B: Calcareous oozetarget 2. A: Abyssal claytarget 3. E: Siliceous oozetarget 4. C: Mid-ocean ridgetarget 5. F: Upwelling, cool watertarget 6. D: Calcite compensation depth (CCD)

What is the approximate depth of the calcite compensation depth (CCD) in the ocean?

3 miles (4.5 kilometers)

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.

Which of the following explains why calcareous ooze is sometimes found below the calcite compensation depth (CCD)?

Calcareous ooze can be deposited above the CCD and covered with other sediment, which protects it as the tectonic plate, and the ooze moves into deeper water.

Where is calcareous ooze most likely to be found in surface sediments in the ocean?

Calcareous ooze is most likely to be found in relatively shallow areas with warm surface water.

Part complete 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.

In which setting would calcareous ooze be most likely to form?

On the crest of a seamount under warm surface water.

Part complete 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.

Part complete Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.

biogenous

Part complete 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

The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.

diatoms; radiolarians

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