Question

Source of calcareous ooze in the sea bottom

• A. Glaciers
• B. Precipitation of dissolved nutrients
• C. Radiolarians
• D. Coccolithophores

Hint:

Calcareous oozes cannot accumulate below a certain depth known as the Carbonate Compensation Depth (CCD, typically 4000-5000m), where high pressure and low temperature cause calcium carbonate to dissolve completely.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Pelagic sediments covering the deep ocean floor are classified based on their origin.
Biogenic sediments composed of shell remnants are known as oozes.

Step 2: Detailed Explanation:
Pelagic biogenic oozes must contain at least \(30\%\) skeletal remains of microscopic marine organisms. They are divided into:
- Calcareous oozes: Composed of calcium carbonate (\(\text{CaCO}_3\)), primarily derived from the shells of planktonic Foraminifera and Coccolithophores (unicellular marine algae).
- Siliceous oozes: Composed of silica (\(\text{SiO}_2\)), primarily derived from Radiolarians and Diatoms.

Step 3: Final Answer:
The source of calcareous ooze is Coccolithophores, which corresponds to option (D).