Question

multiple choice question
the ______ is the depth at which the amount of calcareous material preserved falls below 20% of the total sediment.

lysocline
test line
carbonate compensation depth (ccd)

Explanation:

To solve this, we analyze each option:

• Lysocline: The depth where the rate of calcium carbonate dissolution increases rapidly, not related to the 20% threshold of calcareous material in sediment.
• Test line: Not a term related to calcareous sediment depth in oceanography.
• Carbonate Compensation Depth (CCD): Defined as the depth at which the amount of calcareous (calcium carbonate - containing) material preserved in sediments falls below 20% of the total sediment, matching the description.

Answer:

C. carbonate compensation depth (CCD)