What is the difference between sedimentation and flotation?

　The "velocity that separates sedimentation from flotation" depends on how long of a time scale of natural phenomena you are considering.

　Mineral particles fall from the sky sediment at 1 m/day, so if they sediment in individual mineral particles, it could take as long as 5,000 days to reach the seafloor. I explained. In reality, they take about a month to reach the bottom, but even when individual mineral particles settle at 1 m/day, there are cases where we can determine that they have a "sufficient sedimentation rate".

　In open ocean marine sediments, one millimeter accumulates in a thousand years, a thousand millimeters (1 m) in a million years, and a hundred meters in a hundred million years. Considering the sedimentation rate of mineral particles deposited on the seafloor over 100 million years, we can clearly say that even if it takes 5,000 days at 1 m/d, "the sedimentation rate is sufficient".

　On the other hand, what about a fluffy organic particle that settles at 1 m/d? If the particles are decomposed and disappeared by microorganisms in 10 days, they would be described as "not having a sufficient sedimentation rate and disappearing in suspension" in terms of vertical mass transport.

　It is important to describe the particles as "having a sufficient sedimentation rate" and "not having a sufficient sedimentation rate" with some evidence.