What is the particle size/grain size in 'ooze' deposits ?

Question

Accepted Answer

The particle size/grain size in 'ooze' deposits is <0.005 mm because ooze is defined as a fine-grained pelagic sediment accumulating on the deep ocean floor, composed of at least 30% skeletal remains of microscopic organisms. These skeletal remains, primarily composed of silica (siliceous ooze) or calcium carbonate (calcareous ooze), are extremely small. The very nature of these microscopic organisms and their subsequent breakdown into sediment results in particles that fall into the clay-sized category, which is defined as less than 0.005 mm.

Here's why the other options are incorrect:

*   **Option 1: > 256 mm:** This size range corresponds to boulders. Ooze is a fine-grained sediment, not composed of large rocks or boulders.

*   **Option 2: 4 to 64 mm:** This size range corresponds to gravel. Again, ooze is a fine-grained sediment, not composed of gravel-sized particles.

*   **Option 3: 0.5 to 2 mm:** This size range corresponds to sand. While some very coarse biogenic material *might* occasionally be present, the *dominant* and defining characteristic of ooze is its fine-grained nature, primarily composed of clay-sized particles from the breakdown of microscopic organisms. Therefore, sand-sized particles are not representative of the overall composition of ooze.